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+                ATA/ATA-1/ATA-2/IDE/EIDE/etc FAQ
+
+                    Part 1 of ? -- The Basics
+
+                      Version 0b -- 7 Feb 95
+
+             by Hale Landis -- landis@sugs.tware.com
+
+Note:  Major changes from the previous version are marked by a
+   "!" at the left margin on the first line of the changed
+   paragraph.
+
+First the "legal" stuff...
+
+   1) This FAQ is not intended to replace any other FAQ on this
+   subject but is an attempt to provide historical and technical
+   information about the ATA interface.
+
+   2) This FAQ is not an endorsement of any vendor's product(s).
+
+   3) This FAQ is not a recommendation to purchase any vendor's
+   product(s).
+
+   4) Every effort is made to insure that all of the information
+   presented here is not copyrighted, not proprietary and
+   unrestricted.
+
+   4) When opinions are stated they are clearly identified,
+   including the person's name and email address.  Such opinions
+   are offered as long as they contribute to the understanding of
+   the subject being discussed.  No "flames" allowed.
+
+This is the first version of this FAQ.  It will take some time to
+get all the significant information into it so it will be rapidly
+growing and changing during the next several weeks or months.  I
+don't even know how many parts there will be yet!  Versions will
+be numbered with simple integer numbers (no 1.1, 1.2, etc)
+starting at 0.
+
+If you have a question that is not answered here or if you have
+unrestricted material that you would like to contribute, please
+email it to landis@sugs.tware.com.  DO NOT send material that is
+copyrighted, proprietary or otherwise restricted in any way -- I
+can't use such material in this document.
+
+I don't have FTP access to anything at this time so I leave it to
+others to put this at the appropriate FAQ FTP sites.
+
+About myself:  Until recently I worked for Seagate where I was
+one of several people that attended the ATA, ATA-2, PCMCIA and
+SFF meetings for Seagate.  I was also the manager of a software
+development group that created much of the engineering test
+software for ATA hard disk drives.  I am now a consultant and I
+still attend the ATA-2 meetings.
+
+Table of Contents
+-----------------
+
+Part 1 - The Basics
+
+   Glossary
+   Basic Questions
+
+Part 2 - BIOS and Drivers
+
+   TBD
+
+
+Glossary
+--------
+
+Read and understand these terms.  You will be lost and confused
+if you don't!  Many of these are describe in much greater detail
+in other parts of this FAQ.
+
+ATA or AT Attachment
+
+   ATA is the proper and correct name for what most people call
+   IDE.  In this document, ATA refers to all forms of ATA (ATA-1,
+   ATA-2, etc, IDE, EIDE, etc).  The ATA interface uses a single
+   40-conductor cable in most desktop systems.
+
+ATA-1
+
+   ATA-1 is the common name of the original ATA (IDE)
+   specification.  ATA-1 is not an official standard yet.  Final
+   approval is pending.
+
+ATA-2 or ATA Extensions
+
+   ATA-2 is the common name of the new ATA specification.  ATA-2
+   is still in early draft form and has not been submitted for
+   approval as an official standard.
+
+ATA-3
+
+!  ATA-3 is the common name of a future version of the ATA
+   specification.  The ATA-3 working group has held several
+   meeting but the only things adopted so far are a DMA
+   version of the Identify command, a description of
+   "device 1 only configurations" and a set of "security"
+   commands.
+
+!  There is much discussion going on concerning merging ATA-3
+   with ATAPI.  This will require some kind of "command overlap"
+   capability.  The details of this are consumming much of the
+   meeting time.
+
+ATAPI or ATA Packet Interface
+
+   ATAPI is a proposed new interface specification.  Initially it
+   will probably be used for CD-ROM and tape devices.  It uses
+   the ATA hardware interface at the physical level but uses a
+   subset of the SCSI command set at the logical level.  The
+   ATAPI specification work is currently being done in the SFF
+   committee.
+
+!  The ATAPI folks have delayed forwarding their CD-ROM
+   specification from SFF to X3T10 so the X3T10 ATAPI working
+   group has nothing to work on yet and have held no meetings.
+
+! Block Mode
+
+!  Block mode is the name given to the use of the ATA Read
+   Multiple and Write Multiple commands.  These commands generate
+   a single interrupt to the host system for each block of
+   sectors transfered.  The traditional Read Sectors and Write
+   Sectors commands generate an interrupt to the host for each
+   sector transfered.
+
+CAM (Common Access Method) Committee
+
+   The Common Access Method committee, now disbanded, worked on
+   two specifications: the CAM SCSI and CAM ATA specifications.
+   Both specifications were forwarded to the X3T9 committee for
+   further work years ago.
+
+CHS or Cylinder/Head/Sector
+
+   CHS is the old and traditional way to address data sectors on
+   a hard disk.  This style of addressing relates a sector's
+   address to the position of the read/write heads.  In today's
+   ATA devices, all sector addresses used by the host are logical
+   and have nothing to do with the actual physical position of
+   the sector on the media or the actual position of the
+   read/write heads.
+
+Command Block
+Control Block
+
+   These are names given to the I/O register interface used by
+   ATA devices.  It refers to a set of I/O registers, or I/O
+   ports and I/O port addresses used to program the device.
+   These names replace the older term Task File.
+
+DMA or Direct Memory Access
+
+   DMA is a method of data transfer between two devices that does
+   not use the system's main processor as part of the data path.
+   DMA requires lots of hardware:  a DMA arbitration unit, a DMA
+   data transfer unit and host bus signals that enable the DMA
+   controller to assume control of the host system's bus.  When
+   the DMA controller has control of the host system's bus, it
+   moves data between the two devices by generating the
+   appropriate bus read/write cycles.  For the ATA READ DMA
+   command this means generating an I/O read cycle and then a
+   memory write cycle for each 16-bit word being transferred.
+   For the ATA WRITE DMA command, a memory read cycle is followed
+   by an I/O write cycle for each 16-bit word transferred.
+
+EIDE or Enhanced IDE
+
+   EIDE is a marketing program started by Western Digital to
+   promote certain ATA-2 features including ATAPI.  WD has
+   encouraged other product vendors to mark their products as
+   "EIDE compatible" or "EIDE capable".
+
+ESDI
+
+   See MFM.
+
+Fast ATA
+
+   Fast ATA is a Seagate marketing program used to promote
+   certain ATA-2 features in newer ATA devices.  Seagate has
+   encouraged other product vendors to mark their products as
+   "Fast ATA compatible" or "Fast ATA capable".
+
+Host or Host System
+
+   The computer system that the ATA device is attached to.
+
+HBA or Host Bus Adapter or Host Adapter
+
+   The hardware that converts host bus signals to/from ATA
+   interface signals.  An ATA-1 host adapter is generally a very
+   simple piece of hardware.  An ATA-2 host adapter can be simple
+   or complex.
+
+IDE
+
+   IDE can mean any number of things:  Imbedded Device (or Drive)
+   Electronics (yes, you can spell embedded with an "i"),
+   Intelligent Device (or Drive) Electronics, etc.  The term IDE
+   is the trademark of someone (Western Digital does not claim
+   IDE as theirs but they do claim EIDE).  Many hard disk vendors
+   do not use IDE to describe their products to avoid any
+   trademark conflicts.
+
+LBA or Logical Block Addressing
+
+   LBA is a newer (for ATA it is newer) way to address data
+   sectors on a hard disc.  This style of addressing uses a
+   28-bit binary number to address a sector.  LBA numbers start
+   at zero.  In today's ATA devices, all sector addresses used by
+   the host are logical and have nothing to do with the actual
+   physical location of the sector on the media.
+
+Local Bus
+
+   Usually this refers to the processor's local bus in a high
+   performance computer system.  Usually the processor, the
+   external processor instruction/data cache, the main memory
+   controller and the bridge controller for the next low speed
+   system bus, for example, a PCI bus, are located on the local
+   bus.  Lower speed local buses may have connectors that allow
+   the attachment of other devices.  For example, the VL-Bus is a
+   local bus that can allow attachment of video, SCSI or ATA
+   controllers.  It is very difficult to attach other devices to
+   high speed (say faster than 100MHz) local buses due to
+   electrical restrictions that come into play at those higher
+   speeds.
+
+Master
+
+   ATA device 0.  Device 0, the master, is the "master" of
+   nothing.  See Slave.
+
+Megabyte or MB
+
+   Megabyte or MB is 1,000,000 bytes or 10^6 bytes.  IT IS NOT
+   1,048,576 bytes or 2^20 bytes, repeat NOT!
+
+MFM
+
+   In this document MFM refers to any of the older hard disk
+   controller interfaces, MFM, RLL and ESDI.  It is used to
+   describe any hard disk controller that uses the Task File
+   interface on the host side and the ST506/ST412 interface
+   on the drive side.
+
+OS
+
+   Operating System.
+
+PC Card ATA
+PCMCIA
+
+   We can thank the Personal Computer Memory Card International
+   Association for the PC Card specification.  The PCMCIA is a
+   nonprofit industry association.  The PC Card ATA
+   specification is another form of the ATA interface used by
+   PCMCIA compatible ATA devices.  This interface uses the PCMCIA
+   68-pin connector.  Most 68-pin ATA devices are dual mode --
+   they can operate as either a PCMCIA PC Card ATA device or as a
+   68-pin ATA device.
+
+PCI
+
+   We can thank Intel and the other members of the PCI committee
+   for the PCI bus specification.  PCI is intended to be the next
+   high performance computer bus.  PCI is not generally described
+   as a processor local bus.
+
+PIO or Programmed Input/Output
+
+   PIO is a method of data transfer between two devices that uses
+   the system's main processor as part of the data path.  On
+   x86 systems, the REP INS and REP OUT instructions
+   implement this data transfer method.  INS reads and I/O port
+   and writes the data into memory.  OUTS reads data from memory
+   and writes the data to an I/O port.  Each time an INS or OUTS
+   instruction is executed, the memory address is updated.  The
+   REP prefix causes the instructions to be repeated until a
+   counter reaches zero.
+
+RLL
+
+   See MFM.
+
+Slave
+
+   ATA device 1.  Device 1, the slave, is a "slave" to nothing.
+   See Master.
+
+Task File
+
+   This is the name given to the I/O register interface used by
+   MFM controllers.  It refers to a set of I/O registers, or I/O
+   ports and I/O port addresses used to program the controller.
+   In ATA, this name has been replaced by the terms Command Block
+   and Control Block.
+
+SCSI
+
+   See the SCSI FAQ.
+
+SFF or Small Form Factor
+
+   The SFF committee is an ad hoc committee formed by most of the
+   major storage device and system vendors to set standards for
+   the physical layout of hard disk and other devices.  SFF has
+   published many specifications that describe the physical
+   mounting and connector specifications for hard disk devices,
+   including ATA devices.  During a brief period of time when the
+   X3T9 committee was not doing much work on the ATA-1 interface,
+   the SFF committee published several specifications that were
+   not really part of the original SFF charter.  Most, if not
+   all, of these nonphysical specifications have now been
+   incorporated into the latest X3T9 or X3T10 ATA specifications.
+   ATAPI is currently an SFF specification.
+
+ST506 and ST412
+
+   This is the common name for the hard disk controller to hard
+   disk drive interface used by MFM, RLL and ESDI controllers and
+   disk drives.  ST stands for Seagate Technology.  The ST506 and
+   ST412 were the Seagate products that set the de facto
+   standards for this interface many years ago.  This interface
+   is composed of two cables:  a 34-conductor and a 20-conductor
+   cable.
+
+VESA and VL-Bus
+
+   We can thank the Video Electronics Standards Association for
+   the VESA Local Bus or VL-Bus specification.  The VL-Bus is one
+   example of a local bus.  VESA is a nonprofit industry
+   association like the PCMCIA.
+
+WG or Working Group
+
+   The actual work on various specifications and standards
+   documents within the X3T9, X3T10 and SFF committees happens in
+   working group meetings.  Most WG meetings are held monthly.
+
+X3T9 and X3T10
+
+   These are the names of the official standards committees that
+   have worked on the ATA-1 and ATA-2 specifications.  X3T9 was
+   responsible for the SCSI and ATA-1 specifications and
+   standards.  X3T10 has replaced X3T9 and is now responsible for
+   the current SCSI and ATA specifications and standards work.
+
+528MB
+
+   This term is used in this document to describe the capacity
+   boundary that exists in most x86 system software.  This
+   boundary limits the size of an ATA disk drive to 528MB.  For
+   cylinder/head/sector style addressing of disk data sectors,
+   this number is computed as follows:
+
+   a) the number of cylinders are limited to 1024, numbered
+   0-1023.
+
+   b) the number of heads (per cylinder) are limited to 16,
+   numbered 0-15,
+
+   c) the number of sectors (per track) are limited to 63,
+   numbered 1-63.
+
+   d) a sector is 512 bytes,
+
+   e) 528MB means the following values:
+
+      ( 1024 * 16 * 63 ) or 1,032,192 data sectors
+
+      or
+
+      ( 1024 * 16 * 63 * 512 ) or 528,482,304 bytes.
+
+68-pin ATA
+
+   This refers to a variation of the ATA interface that uses the
+   PCMCIA 68-pin physical interface but does not use the PCMCIA
+   electrical or logical interface.  Most 68-pin ATA devices are
+   dual mode -- they can operate as either a PCMCIA PC Card ATA
+   device or as a 68-pin ATA device.  This interface was
+   developed within the SFF committee and is now included in
+   ATA-2.
+
+Basic Questions
+---------------
+
+### Where did ATA come from?
+
+   What we now call the ATA-1 interface was developed for Compaq
+   many years ago by Imprimus (then part of CDC, now part of
+   Seagate) and Western Digital.  The first ATA-1 hard disk
+   drives were made by Imprimus but it was Conner that made the
+   interface so popular.
+
+### How is ATA different from MFM?
+
+   From the host software standpoint, ATA is very much like the
+   Task File interface used by MFM controllers.  A properly
+   written host software driver should not notice any difference
+   between the MFM Task File interface and the ATA Command Block
+   interface while doing basic commands such as Read/Write
+   Sectors.
+
+   At the hardware level, ATA uses a single cable between a host
+   bus adapter and the ATA device, where the MFM controller
+   interface uses two cables between the controller and the
+   drive.
+
+   In the MFM environment, the controller is one piece of
+   hardware and the drive another piece of hardware.  Most likely
+   these two pieces of hardware are from different vendors.  The
+   MFM controller is dependent on the design of both the host bus
+   and on the drive.
+
+   In the ATA environment, the host adapter is the one piece of
+   hardware that is dependent on the host system bus design.  The
+   ATA interface is (mostly) system independent.  All of the
+   hard disk controller and drive logic is contained in the ATA
+   device hardware.  This gives the hard disk designer complete
+   control over both the controller and drive functions.
+
+### Why is ATA so popular?
+
+   Two basic things make ATA so popular today:  cost and hard
+   disk drive technology.  An ATA-1 host adapter is cheap,
+   usually much less than $25US and it uses only one cable.  On
+   the technology side, current hard disk features, such as,
+   defect handling, error recovery, zone recording, cache
+   management and power management require that the controller be
+   fully integrated with the read/write channel, the servo system
+   and spindle hardware of the disk drive.
+
+### What are the basics of the ATA interface?
+
+   The ATA interface is a very simple interface based on an ISA
+   bus I/O device architecture.  The interface consists of two
+   sets of I/O registers, mostly 8-bit, for passing command and
+   status information.  The registers are like a set of mail
+   boxes with a door on front and back connected such that both
+   doors can not be open at the same time.  The front door is
+   open when the Busy bit in the Status register is zero and the
+   host can read and write the registers.  The back door is open
+   when the Busy bit in the Status register is one and the ATA
+   device can read or write the registers.
+
+   The physical interface contains just enough signals for a 16
+   bit data bus, five register address bits, and a few control
+   signals like read register, write register and reset.
+
+   ATA devices look like traditional hard disk
+   drives even though some are not really a hard disc with
+   rotating platters.  User data is recorded in 512 byte sectors.
+   Each sector has a sector address.  There are two ways to
+   express sector addresses:  by cylinder/head/sector (CHS) or by
+   logical block address (LBA).  CHS is standard, LBA is optional.
+
+### What is EIDE or Fast ATA?
+
+   Both are marketing programs used to promote various ATA-2
+   features, mostly the faster data transfer rates defined by
+   ATA-2.
+
+   ---
+
+   WD defines EIDE as:
+
+   * Support for drives larger than 528MB.
+
+   * Support for two connectors to allow up to four drives.
+
+   * Support for CD-ROM and tape peripherals.
+
+   * Support for 11.1/16.6 Mbytes/second, I/O Channel Ready PIO
+     data transfers.
+
+   * Support for 13.3/16.6 Mbytes/second, DMA data transfers.
+
+   ---
+
+???Seagate defines Fast ATA as:
+
+   * Support for PIO mode 3 (11.1 MB/sec) and DMA mode 1(13.3
+     MB/sec).
+
+   * Support for Multi-sector [Read/Write Multiple] transfers.
+
+   * Support for >528 MB.
+
+   * Support for Identify Drive Extensions & Set Transfer Mode
+     Extensions.
+
+   * Backward compatibility with ATA-1.
+
+   ---
+
+   What does all of this mean to us?
+
+   Support for the ATA-2 high speed PIO and DMA data transfer
+   modes is both a hardware and software issue.
+
+   Support for more than one hard disc controller (or ATA host
+   adapter) requires the BIOS and/or the operating system to
+   support more than one Task File or Command/Control Block
+   register set on the host bus.
+
+   The 528MB problem is due to the original design of the x86
+   BIOS which limits cylinders to 1024 and sectors to 63.  The
+   ATA interface allows up to 65,535 cylinders, 16 heads and 255
+   sectors -- that's about 136GB (137GB if is LBA is used).
+   Support for devices over 528MB requires the BIOS and/or
+   operating system to support some form of CHS translation.
+   Note that LBA alone does not solve this problem (in fact,
+   LBA may make things more complex).
+
+   Support for CD-ROM and tape will probably be done via the
+   ATAPI interface which uses a different command structure than
+   ATA.  That makes ATAPI another host software issue.
+
+### What does an ATA-1 host adapter do?
+
+   An ATA-1 host adapter is a simple piece of logic whose main
+   purpose is to reduce the system bus address lines from 12 (or
+   more) down to 5. It may also buffer some signals giving some
+   degree of electrical isolation between the host bus (usually
+   an ISA or EISA bus) and the ATA bus.  In ATA-1, the ATA
+   interface is controlled directly by the host bus so that all
+   timings are controlled by the host bus timing.
+
+### What does an ATA-2 host adapter do?
+
+   This answer is complex because it depends on how smart your
+   ATA-2 host adapter is.  First, an ATA-2 host adapter supports
+   the ATA-2 higher speed data transfer rates.  That requires
+   that the host adapter is attached to something other than an
+   ISA or EISA bus.  Second, an ATA-2 host adapter may perform
+   32-bit wide transfers on the host bus.  This requires FIFO
+   logic and data buffers in the host adapter.  Third, an ATA-2
+   host adapter may use a different data transfer protocol on the
+   host side than is used on the ATA device side.
+
+! ### Can I put an ATA-2 device on an ATA-1 host adapter?
+! ### Can I put an ATA-1 device on an ATA-2 host adapter?
+
+   The answer to both questions is yes, as long as the electrical
+   timing specifications of the device are not violated.  In
+   general it is impossible for an ATA-1 host adapter to violate
+   the specifications of an ATA-2 device.  It is possible for an
+   ATA-2 host adapter to violate the timing specifications of an
+   ATA-1 device but this is not common.  Hoever, host adapter
+   hardware design errors or software driver bugs can cause such
+   a problem.  The result will be corrupted data read or written
+   to the ATA-1 device.
+
+! ### I have an ATA-2 host adapter with an ATA-2 device.  I want to
+! ### add an ATA-1 device to this host adapter.  Can I run the ATA-2
+! ### device in its ATA-2 data transfer modes?
+
+   Sorry, *NO* you can *NOT* run the new drive in its faster data
+   transfer modes.  Be very careful, most of the ATA-2 host
+   adapter vendors don't have anything in their setup
+   documentation or software to prevent this sort of thing.
+
+   When you run the new drive at a data transfer speed that is
+   faster than the older drive can support, you are violating the
+   electrical interface setup and hold times on the older drive.
+   There is no telling what the older drive will do about this,
+   but you are asking for data corruption and other nasty
+   problems on your older drive.
+
+### How many disk controllers and/or ATA host adapters and/or
+### SCSI host adapters can I put in my system?
+
+   From a hardware standpoint -- as many as you want as long as
+   there are no I/O port address, memory address or interrupt
+   request signal conflicts.  From a software standpoint it is a
+   whole different story.
+
+   First the simple x86 system hard disk controller
+   configurations...
+
+   a) 1 ATA with 1 or 2 drives at I/O port addresses
+   1Fxh/3Fxh using interrupt request 14 (IRQ14).
+
+   b) 1 ATA with 1 drive at I/O port addresses 1Fxh/3Fxh
+   using interrupt request 14 (IRQ14) plus a SCSI with 1 drive.
+
+   c) 1 SCSI with 1 or 2 drives.
+
+   Other configurations are possible but are most likely not
+   supported in the system or SCSI host adapter BIOS.  And if its
+   not supported at the BIOS level, it is unlikely to be
+   supported by an operating system, especially DOS.  The primary
+   reason the above configurations are so restrictive is that the
+   original IBM x86 BIOS supported only one MFM controller with a
+   maximum of 2 drives.  This restriction was then coded into
+   much x86 software including many early version of DOS.  The
+   configurations above work because they don't break this old
+   rule.
+
+   Just remember this -- most systems will always boot from
+   the first drive on the first controller.  In a) that is
+   ATA drive 0, in b) that is ATA drive 0, in c) that is
+   SCSI drive 0.
+
+   And now the more complex configurations...
+
+   Once you go beyond the three configurations above all bets are
+   off.  Most likely you will need operating system device
+   drivers in order to access any drives beyond the first two.
+   And now your real problems start especially if you like to run
+   more than one operating system!
+
+   If you do run more than one OS, then you need equivalent
+   drivers for each system if you would like to access all the
+   drives.  Plus it would be nice if all the drivers configured
+   the drives in the same manner and supported all the possible
+   partitioning schemes and partition sizes.  It would be
+   especially nice if a driver would not destroy the data in a
+   partition just because it did not understand the file system
+   format in that partition.
+
+   One of the things EIDE promotes is BIOS support for up to four
+   ATA devices -- 2 ATA host adapters each with 1 or 2 drives.
+   The first would be at I/O port addresses 1Fxh/3Fxh using
+   interrupt request 14 (IRQ14) and the second at I/O port
+   addresses 17xh/37xh using interrupt request 15 (IRQ15).
+   Acceptance of this configuration has not been spreading like
+   wild fire through the BIOS world.
+
+   Lets look at a two complex configurations...
+
+   a) 1 ATA with 2 drives and 1 SCSI with 1 or more drives.
+
+   Nice configuration.  The ATA drives would be supported by the
+   system BIOS and the SCSI drives may be, could be, should be,
+   supported by the SCSI host adapter BIOS but probably not.  So
+   in order to use the 2 SCSI drives you probably have to disable
+   the BIOS on the SCSI card and then load a device driver in
+   CONFIG.SYS.  And because the SCSI BIOS is disabled, you then
+   need a SCSI driver for that other OS you run.
+
+   b) 2 ATA with 1 or 2 drives on each.
+
+   Also a nice configuration.  But because the system BIOS
+   probably only supports the first controller address, you'll
+   need a DOS device driver loaded in CONFIG.SYS in order to
+   access the drives on the second controller.  You'll need that
+   driver even if there is only one drive on the first
+   controller.  You also need a similar driver to support the
+   second controller in your other OS.
+
+   Note:  I understand that OS/2 does support both MFM/ATA
+   controller addresses and does allow up to four drives -- I
+   have not confirmed this for myself.
+
+! ### Are disk drives the only ATA devices?
+
+   No.  Over the years there have been ATA tape drives, ATA
+   CD-ROMS and other strange devices.  Most of these are expected
+   to be added to an existing ATA host adapter as the second
+   device (device 1) with an existing ATA disk drive (device 0).
+   In general these require software drivers to operate with your
+   OS.
+
+   Now, we have ATAPI CD-ROM and tape devices that can be placed
+   on an ATA host adapter.  And soon we should see system
+   motherboard BIOS support for booting from an ATAPI CD-ROM
+   device.  The general idea is that an ATAPI device can coexist
+   with an ATA device on the same cable.
+
+! ### What can be done to improve ATA device performance?
+
+   A difficult question.  But the first step is usually to reduce
+   the number of interrupts that the host sees during a read or
+   write command.  ATA disk drives have three types of read/write
+   commands:
+
+   * Read Sectors / Write Sectors -- These commands are the old
+   traditional data transfer commands.  These commands generate
+   one interrupt to the host for each sector transfered.  These
+   are PIO data in and PIO data out commands which use the host
+   processor to transfer the data.
+
+   * Read Multiple / Write Multiple -- These commands where
+   defined in ATA-1 but were not used very much until recently.
+   These commands generate one interrupt to the host for each
+   block of sectors transfered.  The number of sector per block
+   is generally 4, 8 or 16.  However, when 1 sector per block is
+   used, these commands are the same as the Read/Write Sectors
+   commands.  These are PIO data in and PIO data out commands
+   which use the host processor to transfer the data.
+
+   * Read DMA / Write DMA -- These commands where defined in
+   ATA-1 but were not used very much until recently.  The main
+   reason for not using them was that x86 system DMA transfer
+   rates are much slower than PIO.  However, these command do
+   generate a single interrupt at the completion of the command.
+
+   Now see the next question...
+
+! ### What else can be done to improve ATA device performance?
+! ### -or-
+! ### What is PIO mode "x" ?
+
+   An even more difficult question.  The second step is usually
+   to increase the rate at which the host transfers data.
+
+   (Ahh...  I can see the funny look on your face from here.  You
+   are saying to yourself:  "the rate at which the host transfers
+   data? doesn't this guy have things backwards?"  Read on...)
+
+   The rate at which data is transferred to or from an ATA device
+   is determined by only one thing:  the PIO or DMA cycle time
+   the host uses.  No, the drive does not have much to do with
+   this!  The only requirement is that the host not exceed the
+   minimum PIO or DMA cycle times that the device supports.  For
+   example, during a PIO read command when the device signals an
+   interrupt to the host this means that the device is waiting
+   for the host to read the next sector or block of sectors from
+   the drive.  The host must execute a REP INSW instruction to do
+   transfer the data.  The rate at which the host executes this
+   instruction determines the PIO cycle time.  Technically, for a
+   read command, the cycle time is the time from the host
+   assertion of the I/O Read signal to the next time the host
+   asserts the I/O Read signal.
+
+   Be careful when looking at the table below -- the data rate is
+   the data transfer rate achieved while transfering the sector
+   or block or sectors.  It is an "instantanous" data rate.  The
+   overall data transfer rate for a command includes many time
+   consuming events such as the amount of time the host requires
+   to process an interrupt.  Note that on many fast ATA drives
+   today, the time it takes the host to process an interrupt is
+   frequently greater than the time required to transfer the
+   sector of block of sectors for that interrupt!  It is not
+   uncommon for the host overhead to reduce the data rate to 1/2
+   or 1/3 of the instantanous rate shown here.
+
+   The ATA PIO modes are defined as follows:
+
+   PIO   min cycle  data  comment
+   mode    time     rate
+
+    0      ???ns     ?MB  the rate at which a system
+                          running at 4.77MHZ could
+                          execute the REP INSW.
+
+    1      ???ns     ?MB  the rate at which a system
+                          running at 6MHz could
+                          execute the REP INSW.
+
+    2      240ns     8MB  the rate at which a system
+                          running at 8MHz could
+                          execute the REP INSW.
+
+    3      180ns    13MB  requires an ATA-2
+                          host adapter.
+
+    4      120ns    16MB  requires an ATA-2
+                          host adapter.
+
+   The complete description of the PIO (and DMA modes is much
+   more complex and will be cover in more detail later in this
+   FAQ.
+
+### Do I need BIOS or OS drivers to support more than 528MB?
+
+   Warning:  Read the previous question before reading this one.
+
+   Maybe, probably, yes.  The answer to this *very* complex and
+   will be discussed in detail in Part 2. Here is the brief
+   answer...
+
+   A traditional x86 system BIOS supports only CHS mode
+   addressing with cylinders limited to 1024, heads limited to 16
+   and sectors limited to 63.  This allows addressing of drives
+   up to 528MB.  These limitations come from the INT 13
+   read/write calls that combine a 10-bit cylinder number with a
+   6-bit sector number into a 16-bit register.
+
+   Note that this is entirely a software problem:  the ATA
+   interface supports up to 65,535 cylinders, 16 heads and 255
+   sectors.
+
+   While the head number usually requires only 4-bits, up to 6 or
+   8 bits are available in the INT 13 interface.  This fact has
+   allowed the SCSI folks to support big drives by increasing the
+   number of heads above 16.  The SCSI host adapter BIOS converts
+   this "fake" CHS address to a different CHS or an LBA when it
+   issues a read/write command to the drive.  The following table
+   shows some approximate drives sizes and the "fake" CHS
+   parameters that you may see from a SCSI BIOS:
+
+      cyl    head    sector   size
+
+      1024     16        63   512MB
+      1024     32        63     1GB
+       512     64        63     1GB
+      1024     64        63     2GB
+      1024    256        63     8GB
+
+   The last entry represents the largest possible drive that
+   a traditional INT 13 BIOS can support.
+
+   The system BIOS folks *must* start supporting drives over
+   528MB in their BIOS by implementing some type of CHS
+   translation.  To date, few systems have such BIOS.  And here
+   is the bad part:  Microsoft says that the BIOS *must*
+   support it in order to use it in their OS.  The algorithm is
+   simple (but warning:  this is not the complete algorithm!):
+
+      INT 13 input    action            ATA interface
+
+      cyl number      "multiply" by n   modified cyl number
+      head number     "divide" by n     modified head number
+      sector number   nothing           sector number
+
+   The value of n must be selected such that the modified head
+   number is less than 16.
+
+   LBA addressing at the hard disk drive level or at the BIOS or
+   driver level is another solution.  This solution will probably
+   not be popular for several more years.  It requires that the
+   BIOS people implement a new INT 13 interface, called the
+   Microsoft/IBM Extensions and that the OS people start using
+   this new BIOS interface.  Few system BIOS support this
+   alternative interface today.  Without this new interface, LBA
+   support at the hard disk drive level is not required.
+
+   So most of us have older systems without much possibility of
+   getting a BIOS upgrade, so what do we do?  Well we must obtain
+   one of the many driver products that are on the market that
+   live in one of the disk boot sectors and "take over" the
+   system BIOS INT 13 with an INT 13 that supports the
+   translation.  The biggest problem with this is that the
+   replacement INT 13 BIOS must live someplace in memory.  For
+   DOS based systems, it can usually live at the top of the 640K
+   of memory and DOS is made to think that that part of memory,
+   usually around 8K bytes, does not exist.  But the protected
+   mode OS's don't like this and usually wipe out the driver when
+   they load their kernel.  So if you plan to run multiple OS's
+   on your system, buyer beware!
+
+   Then there is the Windows problem:  the standard FastDisk
+   driver in Windows does *not* support such translation schemes
+   and can not be enabled.  So make sure the driver you
+   purchase also comes with a Windows FastDisk replacement.
+
+   Buyer beware!
+
+### Do I need BIOS or OS drivers to support the ATA-2 data
+### transfer rates?
+
+   Warning:  Read the previous two questions before reading this
+   one.
+
+   Maybe, probably, yes.  The answer to this *very* complex and
+   will be discussed in detail in Part 2. Here is the brief
+   answer...
+
+   If you have a new ATA drive that supports the advanced PIO or
+   DMA data transfer rates (ATA-2 PIO Mode 3 or 4, or, ATA-2 DMA
+   Mode 1 or 2) then you also must have a new ATA host adapter
+   that attaches to the VL-Bus or PCI bus or some other high
+   speed bus (probably a 32-bit bus) in your system.  That host
+   adapter has I/O registers of its own that are used to control
+   its advanced features.  Controlling those advanced features
+   requires software -- either in the system INT 13 BIOS or in a
+   INT 13 BIOS on the host adapter card or in a driver loaded
+   via the boot record or later by your OS.
+
+   Depending on how that host adapter works you may also
+   need a Windows FastDisk replacement in order to use the high
+   speed data transfer modes in Windows.
+
+   Buyer beware!
+
+### I just purchased a new high speed host adapter for my VL-Bus
+### (or PCI bus) system and a new 540MB hard disk.  How do I get
+### full use out of all this new hardware?
+
+   Did you read the previous three questions?
+
+   You need BIOS or driver software and a Windows FastDisk
+   replacement.  These *must* support both CHS translation
+   (because your drive is over 528MB) and the host adapter
+   hardware (to use the high speed data transfer rates).
+
+   Some drivers on the market today use LBA addressing on the
+   ATA interface to get over 528MB.  This may make your disk
+   partition(s) unreadable by another OS.
+
+   Check the hardware and software specifications of the product
+   before you buy it!  Ask lots of questions -- you probably get
+   lots of incorrect or misleading answers -- be prepared for
+   that!  If you plan to run something other than DOS and
+   Windows, especially if you plan a "dual boot" or "boot
+   manager" environment, be real careful.
+
+   Buyer beware!
+
+   OPINION:  I know of only one product that supports all of this
+   new hardware, supports over 528MB *and* supports most of the
+   current OS's that are shipping including several in shipping
+   in beta form.  The product is from a small two person company
+   that is trying to sell the product on an OEM basis and not in
+   the retail market.  - Hale Landis <landis@sugs.tware.com>
+
+/end part 1/
+-- 
+\\===============\\=======================\\
+ \\  Hale Landis  \\      303-548-0567     \\
+ // Niwot, CO USA // landis@sugs.tware.com //
+//===============//=======================//

src/etc/etc.i386/INSTALL.chs

@@ -0,0 +1,890 @@
+                 How It Works -- CHS Translation
+
+            Plus BIOS Types, LBA and Other Good Stuff
+
+                           Version 4a
+
+             by Hale Landis (landis@sugs.tware.com)
+
+THE "HOW IT WORKS" SERIES
+
+This is one of several How It Works documents.  The series
+currently includes the following:
+
+* How It Works -- CHS Translation
+* How It Works -- Master Boot Record
+* How It Works -- DOS Floppy Boot Sector
+* How It Works -- OS2 Boot Sector
+* How It Works -- Partition Tables
+
+
+Introduction (READ THIS!)
+-------------------------
+
+This is very technical.  Please read carefully.  There is lots of
+information here that can sound confusing the first time you read
+it.
+
+Why is an understanding of how a BIOS works so important?  The
+basic reason is that the information returned by INT 13H AH=08H
+is used by FDISK, it is used in the partition table entries
+within a partition record (like the Master Boot Record) that are
+created by FDISK, and it is used by the small boot program that
+FDISK places into the Master Boot Record.  The information
+returned by INT 13H AH=08H is in cylinder/head/sector (CHS)
+format -- it is not in LBA format.  The boot processing done by
+your computer's BIOS (INT 19H and INT 13H) is all CHS based.
+
+Read this so that you are not confused by all the false
+information going around that says "LBA solves the >528MB
+problem".
+
+Read this so that you understand the possible data integrity
+problem that a WD EIDE type BIOS creates.  Any BIOS that has a
+"LBA mode" in the BIOS setup could be a WD EIDE BIOS.  Be very
+careful and NEVER chage the "LBA mode" setting after you have
+partitioned and installed your software.
+
+History
+-------
+
+Changes between this version and the preceeding version are
+marked by "!" at left margin of the first line of a changed
+or new paragraph.
+
+Version 4 --  BIOS Types 8 and 10 updated.
+
+Version 3 -- New BIOS types found and added to this list.  More
+   detailed information is listed for each BIOS type.  A section
+   describing CHS translation was added.
+
+Version 2 -- A rewrite of version 1 adding BIOS types not
+   included in version 1.
+
+Version 1 -- First attempt to classify the BIOS types and
+   describe what each does or does not do.
+
+Definitions
+-----------
+
+* 528MB - The maximun drive capacity that is supported by 1024
+   cylinders, 16 heads and 63 sectors (1024x16x63x512).  This
+   is the limit for CHS addressing in the original IBM PC/XT
+   and IBM PC/AT INT 13H BIOS.
+
+* 8GB - The maximum drive capacity that can be supported by 1024
+   cylinders, 256 heads and 63 sectors (1024x256x63x512).  This
+   is the limit for the BIOS INT 13H AH=0xH calls.
+
+* ATA - AT Attachment -- The real name of what is widely known
+   as IDE.
+
+* CE Cylinder - Customer Engineering cylinder.  This is the
+   last cylinder in P-CHS mode.  IBM has always reserved this
+   cylinder for use of disk diagnostic programs.  Many BIOS do
+   not account for it correctly.  It is of questionable value
+   these days and probably should be considered obsolete.
+   However, since there is no industry wide agreement, beware.
+   There is no CE Cylinder reserved in the L-CHS address.  Also
+   beware of diagnostic programs that don't realize they are
+   operating in L-CHS mode and think that the last L-CHS cylinder
+   is the CE Cylinder.
+
+* CHS - Cylinder/Head/Sector.  This is the traditional way to
+   address sectors on a disk.  There are at least two types
+   of CHS addressing:  the CHS that is used at the INT 13H
+   interface and the CHS that is used at the ATA device
+   interface.  In the MFM/RLL/ESDI and early ATA days the CHS
+   used at the INT 13H interface was the same as the CHS used at
+   the device interface.
+
+   Today we have CHS translating BIOS types that can use one CHS
+   at the INT 13H interface and a different CHS at the device
+   interface.  These two types of CHS will be called the logical
+   CHS or L-CHS and the physical CHS or P-CHS in this document.
+   L-CHS is the CHS used at the INT 13H interface and P-CHS is
+   the CHS used at the device interface.
+
+   The L-CHS used at the INT 13 interface allows up to 256 heads,
+   up to 1024 cylinders and up to 63 sectors.  This allows
+   support of up to 8GB drives.  This scheme started with either
+   ESDI or SCSI adapters many years ago.
+
+   The P-CHS used at the device interface allows up to 16 heads
+   up to 65535 cylinders, and up to 63 sectors.  This allows
+   access to 2^28 sectors (136GB) on an ATA device.  When a P-CHS
+   is used at the INT 13H interface it is limited to 1024
+   cylinders, 16 heads and 63 sectors.  This is where the old
+   528MB limit originated.
+
+   ATA devices may also support LBA at the device interface.  LBA
+   allows access to approximately 2^28 sectors (137GB) on an ATA
+   device.
+
+   A SCSI host adapter can convert a L-CHS directly to an LBA
+   used in the SCSI read/write commands.  On a PC today, SCSI is
+   also limited to 8GB when CHS addressing is used at the INT 13H
+   interface.
+
+* EDPT - Enhanced fixed Disk Parameter Table -- This table
+   returns additional information for BIOS drive numbers 80H and
+   81H.  The EDPT for BIOS drive 80H is pointed to by INT 41H.
+   The EDPT for BIOS drive 81H is pointed to by INT 46H.  The
+   EDPT is a fixed disk parameter table with an AxH signature
+   byte.  This table format returns two sets of CHS information.
+   One set is the L-CHS and is probably the same as returned by
+   INT 13H AH=08H.  The other set is the P-CHS used at the drive
+   interface.  This type of table allows drives with >1024
+   cylinders or drives >528MB to be supported.  The translated
+   CHS will have <=1024 cylinders and (probably) >16 heads.  The
+   CHS used at the drive interface will have >1024 cylinders and
+   <=16 heads.  It is unclear how the IBM defined CE cylinder is
+   accounted for in such a table.  Compaq probably gets the
+   credit for the original definition of this type of table.
+
+* FDPT - Fixed Disk Parameter Table - This table returns
+   additional information for BIOS drive numbers 80H and 81H.
+   The FDPT for BIOS drive 80H is pointed to by INT 41H.  The
+   FDPT for BIOS drive 81H is pointed to by INT 46H.  A FDPT does
+   not have a AxH signature byte.  This table format returns a
+   single set of CHS information.  The L-CHS information returned
+   by this table is probably the same as the P-CHS and is also
+   probably the same as the L-CHS returned by INT 13H AH=08H.
+   However, not all BIOS properly account for the IBM defined CE
+   cylinder and this can cause a one or two cylinder difference
+   between the number of cylinders returned in the AH=08H data
+   and the FDPT data.  IBM gets the credit for the original
+   definition of this type of table.
+
+* LBA - Logical Block Address.  Another way of addressing
+   sectors that uses a simple numbering scheme starting with zero
+   as the address of the first sector on a device.  The ATA
+   standard requires that cylinder 0, head 0, sector 1 address
+   the same sector as addressed by LBA 0. LBA addressing can be
+   used at the ATA interface if the ATA device supports it.  LBA
+   addressing is also used at the INT 13H interface by the AH=4xH
+   read/write calls.
+
+* L-CHS -- Logical CHS.  The CHS used at the INT 13H interface by
+     the AH=0xH calls.  See CHS above.
+
+* MBR - Master Boot Record (also known as a partition table) -
+   The sector located at cylinder 0 head 0 sector 1 (or LBA 0).
+   This sector is created by an "FDISK" utility program.  The MBR
+   may be the only partition table sector or the MBR can be the
+   first of multiple partition table sectors that form a linked
+   list.  A partition table entry can describe the starting and
+   ending sector addresses of a partition (also known as a
+   logical volume or a logical drive) in both L-CHS and LBA form.
+   Partition table entries use the L-CHS returned by INT 13H
+   AH=08H.  Older FDISK programs may not compute valid LBA
+   values.
+
+* OS - Operating System.
+
+* P-CHS -- Physical CHS.  The CHS used at the ATA device
+   interface.  This CHS is also used at the INT 13H interface by
+   older BIOS's that do not support >1024 cylinders or >528MB.
+   See CHS above.
+
+Background and Assumptions
+--------------------------
+
+First, please note that this is written with the OS implementor
+in mind and that I am talking about the possible BIOS types as
+seen by an OS during its hardware configuration search.
+
+It is very important that you not be confused by all the
+misinformation going around these days.  All OS's that want to be
+co-resident with another OS (and that is all of the PC based OS's
+that I know of) MUST use INT 13H to determine the capacity of a
+hard disk.  And that capacity information MUST be determined in
+L-CHS mode.  Why is this?  Because:  1) FDISK and the partition
+tables are really L-CHS based, and 2) MS/PC DOS uses INT 13H
+AH=02H and AH=03H to read and write the disk and these BIOS calls
+are L-CHS based.  The boot processing done by the BIOS is all
+L-CHS based.  During the boot processing, all of the disk read
+accesses are done in L-CHS mode via INT 13H and this includes
+loading the first of the OS's kernel code or boot manager's code.
+
+Second, because there can be multiple BIOS types in any one
+system, each drive may be under the control of a different type
+of BIOS.  For example, drive 80H (the first hard drive) could be
+controlled by the original system BIOS, drive 81H (the second
+drive) could be controlled by a option ROM BIOS and drive 82H
+(the third drive) could be controlled by a software driver.
+Also, be aware that each drive could be a different type, for
+example, drive 80H could be an MFM drive, drive 81H could be an
+ATA drive, drive 82H could be a SCSI drive.
+
+Third, not all OS's understand or use BIOS drive numbers greater
+than 81H.  Even if there is INT 13H support for drives 82H or
+greater, the OS may not use that support.
+
+Fourth, the BIOS INT 13H configuration calls are:
+
+* AH=08H, Get Drive Parameters -- This call is restricted to
+   drives up to 528MB without CHS translation and to drives up to
+   8GB with CHS translation.  For older BIOS with no support for
+   >1024 cylinders or >528MB, this call returns the same CHS as
+   is used at the ATA interface (the P-CHS).  For newer BIOS's
+   that do support >1024 cylinders or >528MB, this call returns a
+   translated CHS (the L-CHS).  The CHS returned by this call is
+   used by FDISK to build partition records.
+
+* AH=41H, Get BIOS Extensions Support -- This call is used to
+   determine if the IBM/Microsoft Extensions or if the Phoenix
+   Enhanced INT 13H calls are supported for the BIOS drive
+   number.
+
+* AH=48H, Extended Get Drive Parameters -- This call is used to
+   determine the CHS geometries, LBA information and other data
+   about the BIOS drive number.
+
+* the FDPT or EDPT -- While not actually a call, but instead a
+   data area, the FDPT or EDPT can return additional information
+   about a drive.
+
+* other tables -- The IBM/Microsoft extensions provide a pointer
+   to a drive parameter table via INT 13H AH=48H.  The Phoenix
+   enhancement provides a pointer to a drive parameter table
+   extension via INT 13H AH=48H.  These tables are NOT the same
+   as the FDPT or EDPT.
+
+Note:  The INT 13H AH=4xH calls duplicate the older AH=0xH calls
+but use a different parameter passing structure.  This new
+structure allows support of drives with up to 2^64 sectors
+(really BIG drives).  While at the INT 13H interface the AH=4xH
+calls are LBA based, these calls do NOT require that the drive
+support LBA addressing.
+
+CHS Translation Algorithms
+--------------------------
+
+NOTE:  Before you send me email about this, read this entire
+  section.  Thanks!
+
+As you read this, don't forget that all of the boot processing
+done by the system BIOS via INT 19H and INT 13H use only the INT
+13H AH=0xH calls and that all of this processing is done in CHS
+mode.
+
+First, lets review all the different ways a BIOS can be called
+to perform read/write operations and the conversions that a BIOS
+must support.
+
+! * An old BIOS (like BIOS type 1 below) does no CHS translation
+   and does not use LBA.  It only supports the AH=0xH calls:
+
+      INT 13H      (L-CHS == P-CHS)             ATA
+      AH=0xH  --------------------------------> device
+      (L-CHS)                                   (P-CHS)
+
+* A newer BIOS may support CHS translation and it may support
+   LBA at the ATA interface:
+
+      INT 13H        L-CHS                      ATA
+      AH=0xH  --+--> to    --+----------------> device
+      (L-CHS)   |    P-CHS   |                  (P-CHS)
+                |            |
+                |            |    P-CHS
+                |            +--> to    --+
+                |                 LBA     |
+                |                         |
+                |    L-CHS                |     ATA
+                +--> to  -----------------+---> device
+                     LBA                        (LBA)
+
+* A really new BIOS may also support the AH=4xH in addtion to
+   the older AH\0xH calls.  This BIOS must support all possible
+   combinations of CHS and LBA at both the INT 13H and ATA
+   interfaces:
+
+      INT 13H                                   ATA
+      AH=4xH  --+-----------------------------> device
+      (LBA)     |                               (LBA)
+                |
+                |    LBA
+                +--> to    ---------------+
+                     P-CHS                |
+                                          |
+      INT 13H        L-CHS                |     ATA
+      AH=0xH  --+--> to    --+------------+---> device
+      (L-CHS)   |    P-CHS   |                  (P-CHS)
+                |            |
+                |            |    P-CHS
+                |            +--> to    --+
+                |                 LBA     |
+                |                         |
+                |    L-CHS                |     ATA
+                +--> to  -----------------+---> device
+                     LBA                        (LBA)
+
+You would think there is only one L-CHS to P-CHS translation
+algorithm, only one L-CHS to LBA translation algorithm and only
+one P-CHS to LBA translation algorithm.  But this is not so.
+Why?  Because there is no document that standardizes such an
+algorithm.  You can not rely on all BIOS's and OS's to do these
+translations the same way.
+
+The following explains what is widely accepted as the
+"correct" algorithms.
+
+An ATA disk must implement both CHS and LBA addressing and
+must at any given time support only one P-CHS at the device
+interface.  And, the drive must maintain a strick relationship
+between the sector addressing in CHS mode and LBA mode.  Quoting
+the ATA-2 document:
+
+     LBA = ( (cylinder * heads_per_cylinder + heads )
+             * sectors_per_track ) + sector - 1
+
+     where heads_per_cylinder and sectors_per_track are the current
+     translation mode values.
+
+This algorithm can also be used by a BIOS or an OS to convert
+a L-CHS to an LBA as we'll see below.
+
+This algorithm can be reversed such that an LBA can be
+converted to a CHS:
+
+    cylinder = LBA / (heads_per_cylinder * sectors_per_track)
+        temp = LBA % (heads_per_cylinder * sectors_per_track)
+        head = temp / sectors_per_track
+      sector = temp % sectors_per_track + 1
+
+While most OS's compute disk addresses in an LBA scheme, an OS
+like DOS must convert that LBA to a CHS in order to call INT 13H.
+
+Technically an INT 13H should follow this process when
+converting an L-CHS to a P-CHS:
+
+     1) convert the L-CHS to an LBA,
+     2) convert the LBA to a P-CHS,
+
+If an LBA is required at the ATA interface, then this third
+step is needed:
+
+     3) convert the P-CHS to an LBA.
+
+All of these conversions are done by normal arithmetic.
+
+However, while this is the technically correct way to do
+things, certain short cuts can be taken.  It is possible to
+convert an L-CHS directly to a P-CHS using bit a bit shifting
+algorithm.  This combines steps 1 and 2. And, if the ATA device
+being used supports LBA, steps 2 and 3 are not needed.  The LBA
+value produced in step 1 is the same as the LBA value produced in
+step 3.
+
+AN EXAMPLE
+
+Lets look at an example.  Lets say that the L-CHS is 1000
+cylinders 10 heads and 50 sectors, the P-CHS is 2000 cylinders, 5
+heads and 50 sectors.  Lets say we want to access the sector at
+L-CHS 2,4,3.
+
+* step 1 converts the L-CHS to an LBA,
+
+     lba = 1202 = ( ( 2 * 10 + 4 ) * 50 ) + 3 - 1
+
+* step 2 converts the LBA to the P-CHS,
+
+     cylinder =   4 = ( 1202 / ( 5 * 50 )
+         temp = 202 = ( 1202 % ( 5 * 50 ) )
+         head =   4 = ( 202 / 50 )
+       sector =   3 = ( 202 % 50 ) + 1
+
+* step 3 converts the P-CHS to an LBA,
+
+     lba = 1202 = ( ( 4 * 5 + 4 ) * 50 ) + 3 - 1
+
+Most BIOS (or OS) software is not going to do all of this to
+convert an address.  Most will use some other algorithm.  There
+are many such algorithms.
+
+BIT SHIFTING INSTEAD
+
+If the L-CHS is produced from the P-CHS by 1) dividing the
+P-CHS cylinders by N, and 2) multiplying the P-CHS heads by N,
+where N is 2, 4, 8, ..., then this bit shifting algorithm can be
+used and N becomes a bit shift value.  This is the most common
+way to make the P-CHS geometry of a >528MB drive fit the INT 13H
+L-CHS rules.  Plus this algorithm maintains the same sector
+ordering as the more complex algorithm above.  Note the
+following:
+
+     Lcylinder = L-CHS cylinder being accessed
+         Lhead = L-CHS head being accessed
+       Lsector = L-CHS sector being accessed
+
+     Pcylinder = the P-CHS cylinder being accessed
+         Phead = the P-CHS head being accessed
+       Psector = P-CHS sector being accessed
+
+           NPH = is the number of heads in the P-CHS
+             N = 2, 4, 8, ..., the bit shift value
+
+The algorithm, which can be implemented using bit shifting
+instead of multiply and divide operations is:
+
+     Pcylinder = ( Lcylinder * N ) + ( Lhead / NPH );
+         Phead = ( Lhead % NPH );
+       Psector = Lsector;
+
+A BIT SHIFTING EXAMPLE
+
+Lets apply this to our example above (L-CHS = 1000,10,50 and
+P-CHS = 2000, 5, 50) and access the same sector at at L-CHS
+2,4,3.
+
+     Pcylinder = 4 = ( 2 * 2 ) + ( 4 / 5 )
+         Phead = 4 = ( 4 % 5 )
+       Psector = 3 = 3
+
+As you can see, this produces the same P-CHS as the more
+complex method above.
+
+SO WHAT IS THE PROBLEM?
+
+The basic problem is that there is no requirement that a CHS
+translating BIOS followed these rules.  There are many other
+algorithms that can be implemented to perform a similar function.
+Today, there are at least two popular implementions:  the Phoenix
+implementation (described above) and the non-Phoenix
+implementations.
+
+SO WHY IS THIS A PROBLEM IF IT IS HIDDEN INSIDE THE BIOS?
+
+Because a protected mode OS that does not want to use INT 13H
+must implement the same CHS translation algorithm.  If it
+doesn't, your data gets scrambled.
+
+WHY USE CHS AT ALL?
+
+In the perfect world of tomorrow, maybe only LBA will be used.
+But today we are faced with the following problems:
+
+* Some drives >528MB don't implement LBA.
+
+* Some drives are optimized for CHS and may have lower
+   performance when given commands in LBA mode.  Don't forget
+   that LBA is something new for the ATA disk designers who have
+   worked very hard for many years to optimize CHS address
+   handling.  And not all drive designs require the use of LBA
+   internally.
+
+* The L-CHS to LBA conversion is more complex and slower than
+   the bit shifting L-CHS to P-CHS conversion.
+
+* DOS, FDISK and the MBR are still CHS based -- they use the
+   CHS returned by INT 13H AH=08H.  Any OS that can be installed
+   on the same disk with DOS must understand CHS addressing.
+
+* The BIOS boot processing and loading of the first OS kernel
+   code is done in CHS mode -- the CHS returned by INT 13H AH=08H
+   is used.
+
+* Microsoft has said that their OS's will not use any disk
+   capacity that can not also be accessed by INT 13H AH=0xH.
+
+These are difficult problems to overcome in today's industry
+environment.  The result:  chaos.
+
+DANGER TO YOUR DATA!
+
+See the description of BIOS Type 7 below to understand why a
+WD EIDE BIOS is so dangerous to your data.
+
+
+The BIOS Types
+--------------
+
+I assume the following:
+
+a) All BIOS INT 13H support has been installed by the time the OS
+   starts its boot processing.  I'm don't plan to cover what
+   could happen to INT 13H once the OS starts loading its own
+   device drivers.
+
+b) Drives supported by INT 13H are numbered sequentially starting
+   with drive number 80H (80H-FFH are hard drives, 00-7FH are
+   floppy drives).
+
+And remember, any time a P-CHS exists it may or may not account
+  for the CE Cylinder properly.
+
+I have identified the following types of BIOS INT 13H support as
+seen by an OS during its boot time hardware configuration
+determination:
+
+BIOS Type 1
+
+   Origin:  Original IBM PC/XT.
+
+   BIOS call support:  INT 13H AH=0xH and FDPT for BIOS drives
+   80H and 81H.  There is no CHS translation.  INT 13H AH=08H
+   returns the P-CHS.  The FDPT should contain the same P-CHS.
+
+   Description:  Supports up to 528MB from a table of drive
+   descriptions in BIOS ROM.  No support for >1024 cylinders or
+   drives >528MB or LBA.
+
+   Support issues:  For >1024 cylinders or >528MB support, either
+   an option ROM with an INT 13H replacement (see BIOS types 4-7)
+   -or- a software driver (see BIOS type 8) must be added to the
+   system.
+
+BIOS Type 2
+
+   Origin:  Unknown, but first appeared on systems having BIOS
+   drive type table entries defining >1024 cylinders.  Rumored to
+   have originated at the request of Novell or SCO.
+
+   BIOS call support:  INT 13H AH=0xH and FDPT for BIOS drives
+   80H and 81H.  INT 13H AH=08H should return a L-CHS with the
+   cylinder value limited to 1024.  Beware, many BIOS perform
+   a logical AND on the cylinder value.  A correct BIOS will
+   limit the cylinder value as follows:
+
+      cylinder = cylinder > 1024 ? 1024 : cylinder;
+
+   An incorrect BIOS will limit the cylinder value as follows
+   (this implementation turns a 540MB drive into a 12MB drive!):
+
+      cylinder = cylinder & 0x03ff;
+
+   The FDPT will return a P-CHS that has the full cylinder
+   value.
+
+   Description:  For BIOS drive numbers 80H and 81H, this BIOS
+   type supports >1024 cylinders or >528MB without using a
+   translated CHS in the FDPT.  INT 13H AH=08H truncates
+   cylinders to 1024 (beware of buggy implementations).  The FDPT
+   can show >1024 cylinders thereby allowing an OS to support
+   drives >528MB.  May convert the L-CHS or P-CHS directly to an
+   LBA if the ATA device supports LBA.
+
+   Support issues:  Actual support of >1024 cylinders is OS
+   specific -- some OS's may be able to place OS specific
+   partitions spanning or beyond cylinder 1024.  Usually all OS
+   boot code must be within first 1024 cylinders.  The FDISK
+   program of an OS that supports such partitions uses an OS
+   specific partition table entry format to identify these
+   paritions.  There does not appear to be a standard (de facto
+   or otherwise) for this unusual partition table entry.
+   Apparently one method is to place -1 into the CHS fields and
+   use the LBA fields to describe the location of the partition.
+   This DOES NOT require the drive to support LBA addressing.
+   Using an LBA in the partition table entry is just a trick to
+   get around the CHS limits in the partition table entry.  It is
+   unclear if such a partition table entry will be ignored by an
+   OS that does not understand what it is.  For an OS that does
+   not support such partitions, either an option ROM with an INT
+   13H replacement (see BIOS types 4-7) -or- a software driver
+   (see BIOS type 8) must be added to the system.
+
+   Note:  OS/2 can place HPFS partitions and Linux can place
+   Linux partitions beyond or spanning cylinder 1024.  (Anyone
+   know of other systems that can do the same?)
+
+BIOS Type 3
+
+   Origin:  Unknown, but first appeared on systems having BIOS
+   drive type table entires defining >1024 cylinders.  Rumored to
+   have originated at the request of Novell or SCO.
+
+   BIOS call support:  INT 13H AH=0xH and FDPT for BIOS drives
+   80H and 81H.  INT 13H AH=08H can return an L-CHS with more
+   than 1024 cylinders.
+
+   Description:  This BIOS is like type 2 above but it allows up
+   to 4096 cylinders (12 cylinder bits).  It does this in the INT
+   13H AH=0xH calls by placing two most significant cylinder bits
+   (bits 11 and 10) into the upper two bits of the head number
+   (bits 7 and 6).
+
+   Support issues:  Identification of such a BIOS is difficult.
+   As long as the drive(s) supported by this type of BIOS have
+   <1024 cylinders this BIOS looks like a type 2 BIOS because INT
+   13H AH=08H should return zero data in bits 7 and 6 of the head
+   information.  If INT 13H AH=08H returns non zero data in bits
+   7 and 6 of the head information, perhaps it can be assumed
+   that this is a type 3 BIOS.  For more normal support of >1024
+   cylinders or >528MB, either an option ROM with an INT 13H
+   replacement (see BIOS types 4-7) -or- a software driver (see
+   BIOS type 8) must be added to the system.
+
+   Note:  Apparently this BIOS type is no longer produced by any
+   BIOS vendor.
+
+BIOS Type 4
+
+   Origin:  Compaq.  Probably first appeared in systems with ESDI
+   drives having >1024 cylinders.
+
+   BIOS call support:  INT 13H AH=0xH and EDPT for BIOS drives
+   80H and 81H.  If the drive has <1024 cylinders, INT 13H AH=08H
+   returns the P-CHS and a FDPT is built.  If the drive has >1024
+   cylinders, INT 13H AH=08H returns an L-CHS and an EDPT is
+   built.
+
+   Description:  Looks like a type 2 BIOS when an FDPT is built.
+   Uses CHS translation when an EDPT is used.  May convert the
+   L-CHS directly to an LBA if the ATA device supports LBA.
+
+   Support issues:  This BIOS type may support up to four drives
+   with a EDPT (or FDPT) for BIOS drive numbers 82H and 83H
+   located in memory following the EDPT (or FDPT) for drive 80H.
+   Different CHS translation algorithms may be used by the BIOS
+   and an OS.
+
+BIOS Type 5
+
+   Origin:  The IBM/Microsoft BIOS Extensions document.  For many
+   years this document was marked "confidential" so it did not
+   get wide spread distribution.
+
+   BIOS call support:  INT 13H AH=0xH, AH=4xH and EDPT for BIOS
+   drives 80H and 81H.  INT 13H AH=08H returns an L-CHS.  INT 13H
+   AH=41H and AH=48H should be used to get P-CHS configuration.
+   The FDPT/EDPT should not be used.  In some implementations the
+   FDPT/EDPT may not exist.
+
+   Description:  A BIOS that supports very large drives (>1024
+   cylinders, >528MB, actually >8GB), and supports the INT 13H
+   AH=4xH read/write functions.  The AH=4xH calls use LBA
+   addressing and support drives with up to 2^64 sectors.  These
+   calls do NOT require that a drive support LBA at the drive
+   interface.  INT 13H AH=48H describes the L-CHS used at the INT
+   13 interface and the P-CHS or LBA used at the drive interface.
+   This BIOS supports the INT 13 AH=0xH calls the same as a BIOS
+   type 4.
+
+   Support issues:  While the INT 13H AH=4xH calls are well
+   defined, they are not implemented in many systems shipping
+   today.  Currently undefined is how such a BIOS should respond
+   to INT 13H AH=08H calls for a drive that is >8GB.  Different
+   CHS translation algorithms may be used by the BIOS and an OS.
+
+   Note:  Support of LBA at the drive interface may be automatic
+   or may be under user control via a BIOS setup option.  Use of
+   LBA at the drive interface does not change the operation of
+   the INT 13 interface.
+
+BIOS Type 6
+
+   Origin:  The Phoenix Enhanced Disk Drive Specification.
+
+   BIOS call support:  INT 13H AH=0xH, AH=4xH and EDPT for BIOS
+   drives 80H and 81H.  INT 13H AH=08H returns an L-CHS.  INT 13H
+   AH=41H and AH=48H should be used to get P-CHS configuration.
+   INT 13H AH=48H returns the address of the Phoenix defined
+   "FDPT Extension" table.
+
+   Description:  A BIOS that supports very large drives (>1024
+   cylinders, >528MB, actually >8GB), and supports the INT 13H
+   AH=4xH read/write functions.  The AH=4xH calls use LBA
+   addressing and support drives with up to 2^64 sectors.  These
+   calls do NOT require that a drive support LBA at the drive
+   interface.  INT 13H AH=48H describes the L-CHS used at the INT
+   13 interface and the P-CHS or LBA used at the drive interface.
+   This BIOS supports the INT 13 AH=0xH calls the same as a BIOS
+   type 4. The INT 13H AH=48H call returns additional information
+   such as host adapter addresses, DMA support, LBA support, etc,
+   in the Phoenix defined "FDPT Extension" table.
+
+   Phoenix says this this BIOS need not support the INT 13H
+   AH=4xH read/write calls but this BIOS is really an
+   extension/enhancement of the original IBM/MS BIOS so most
+   implementations will probably support the full set of INT 13H
+   AH=4xH calls.
+
+   Support issues:  Currently undefined is how such a BIOS should
+   respond to INT 13H AH=08H calls for a drive that is >8GB.
+   Different CHS translation algorithms may be used by the BIOS
+   and an OS.
+
+   Note:  Support of LBA at the drive interface may be automatic
+   or may be under user control via a BIOS setup option.  Use of
+   LBA at the drive interface does not change the operation of
+   the INT 13 interface.
+
+BIOS Type 7
+
+   Origin:  Described in the Western Digital Enhanced IDE
+   Implementation Guide.
+
+   BIOS call support:  INT 13H AH=0xH and FDPT or EDPT for BIOS
+   drives 80H and 81H.  An EDPT with a L-CHS of 16 heads and 63
+   sectors is built when "LBA mode" is enabled.  An FDPT is built
+   when "LBA mode" is disabled.
+
+   Description:  Supports >1024 cylinders or >528MB using a EDPT
+   with a translated CHS *** BUT ONLY IF *** the user requests
+   "LBA mode" in the BIOS setup *** AND *** the drive supports
+   LBA.  As long as "LBA mode" is enabled, CHS translation is
+   enabled using a L-CHS with <=1024 cylinders, 16, 32, 64, ...,
+   heads and 63 sectors.  Disk read/write commands are issued in
+   LBA mode at the ATA interface but other commands are issued in
+   P-CHS mode.  Because the L-CHS is determined by table lookup
+   based on total drive capacity and not by a multiply/divide of
+   the P-CHS cylinder and head values, it may not be possible to
+   use the simple (and faster) bit shifting L-CHS to P-CHS
+   algorithms.
+
+   When "LBA mode" is disabled, this BIOS looks like a BIOS type
+   2 with an FDPT.  The L-CHS used is taken either from the BIOS
+   drive type table or from the device's Identify Device data.
+   This L-CHS can be very different from the L-CHS returned when
+   "LBA mode" is enabled.
+
+   This BIOS may support FDPT/EDPT for up to four drives in the
+   same manner as described in BIOS type 4.
+
+   The basic problem with this BIOS is that the CHS returned by
+   INT 13H AH=08H changes because of a change in the "LBA mode"
+   setting in the BIOS setup.  This should not happen.  This use
+   or non-use of LBA at the ATA interface should have no effect
+   on the CHS returned by INT 13H AH=08H.  This is the only BIOS
+   type know to have this problem.
+
+   Support issues:  If the user changes the "LBA mode" setting in
+   BIOS setup, INT 13H AH=08H and the FDPT/EDPT change
+   which may cause *** DATA CORRUPTION ***.  The user should be
+   warned to not change the "LBA mode" setting in BIOS setup once
+   the drive has been partitioned and software installed.
+   Different CHS translation algorithms may be used by the BIOS
+   and an OS.
+
+BIOS Type 8
+
+   Origin:  Unknown.  Perhaps Ontrack's Disk Manager was the
+   first of these software drivers.  Another example of such a
+   driver is Micro House's EZ Drive.
+
+   BIOS call support:  Unknown (anyone care to help out here?).
+   Mostly likely only INT 13H AH=0xH are support.  Probably a
+   FDPT or EDPT exists for drives 80H and 81H.
+
+!  Description:  A software driver that "hides" in the MBR such
+   that it is loaded into system memory before any OS boot
+   processing starts.  These drivers can have up to three parts:
+   a part that hides in the MBR, a part that hides in the
+   remaining sectors of cylinder 0, head 0, and an OS device
+   driver.  The part in the MBR loads the second part of the
+   driver from cylinder 0 head 0. The second part provides a
+   replacement for INT 13H that enables CHS translation for at
+   least the boot drive.  Usually the boot drive is defined in
+   CMOS setup as a type 1 or 2 (5MB or 10MB drive).  Once the
+   second part of the driver is loaded, this definition is
+   changed to describe the true capacity of the drive and INT 13H
+   is replaced by the driver's version of INT 13H that does CHS
+   translation.  In some cases the third part, an OS specific
+   device driver, must be loaded to enable CHS translation for
+   devices other than the boot device.
+
+!  I don't know the details of how these drivers respond to INT
+   13H AH=08H or how they set up drive parameter tables (anyone
+   care to help out here?).  Some of these drivers convert the
+   L-CHS to an LBA, then they add a small number to the LBA and
+   finally they convert the LBA to a P-CHS.  This in effect skips
+   over some sectors at the front of the disk.
+
+   Support issues:  Several identified -- Some OS installation
+   programs will remove or overlay these drivers; some of these
+   drivers do not perform CHS translation using the same
+   algorithms used by the other BIOS types; special OS device
+   drivers may be required in order to use these software drivers
+   For example, under MS Windows the standard FastDisk driver
+   (the 32-bit disk access driver) must be replaced by a driver
+   that understands the Ontrack, Micro House, etc, version of INT
+   13H.  Different CHS translation algorithms may be used by the
+   driver and an OS.
+
+!  The hard disk vendors have been shipping these drivers with
+   their drives over 528MB during the last year and they have
+   been ignoring the statements of Microsoft and IBM that these
+   drivers would not be supported in future OS's.  Now it appears
+   that both Microsoft and IBM are in a panic trying to figure
+   out how to support some of these drivers in WinNT, Win95 and
+   OS/2.  It is unclear what the outcome of this will be at this
+   time.
+
+!  NOTE:  THIS IS NOT A PRODUCT ENDORSEMENT!  An alternate
+   solution for an older ISA system is one of the BIOS
+   replacement cards.  This cards have a BIOS option ROM.  AMI
+   makes such a card called the "Disk Extender".  This card
+   replaces the motherboard's INT 13H BIOS with a INT 13H BIOS
+   that does some form of CHS translation.  Another solution for
+   older VL-Bus systems is an ATA-2 (EIDE) type host adapter card
+   that provides a option ROM with an INT 13H replacement.
+
+BIOS Type 9
+
+   Origin:  SCSI host adapters.
+
+   BIOS call support:  Probably INT 13H AH=0xH and FDPT for BIOS
+   drives 80H and 81H, perhaps INT 13H AH=4xH.
+
+   Description:  Most SCSI host adapters contain an option ROM
+   that enables INT 13 support for the attached SCSI hard drives.
+   It is possible to have more than one SCSI host adapter, each
+   with its own option ROM.  The CHS used at the INT 13H
+   interface is converted to the LBA that is used in the SCSI
+   commands.  INT 13H AH=08H returns a CHS.  This CHS will have
+   <=1024 cylinders, <=256 heads and <=63 sectors.  The FDPT
+   probably will exist for SCSI drives with BIOS drive numbers of
+   80H and 81H and probably indicates the same CHS as that
+   returned by INT 13H AH=08H.  Even though the CHS used at the
+   INT 13H interface looks like a translated CHS, there is no
+   need to use a EDPT since there is no CHS-to-CHS translation
+   used.  Other BIOS calls (most likely host adapter specific)
+   must be used to determine other information about the host
+   adapter or the drives.
+
+   The INT 13H AH=4xH calls can be used to get beyond 8GB but
+   since there is little support for these calls in today's OS's,
+   there are probably few SCSI host adapters that support these
+   newer INT 13H calls.
+
+   Support issues:  Some SCSI host adapters will not install
+   their option ROM if there are two INT 13H devices previously
+   installed by another INT 13H BIOS (for example, two
+   MFM/RLL/ESDI/ATA drives).  Other SCSI adapters will install
+   their option ROM and use BIOS drive numbers greater than 81H.
+   Some older OS's don't understand or use BIOS drive numbers
+   greater than 81H.  SCSI adapters are currently faced with the
+   >8GB drive problem.
+
+BIOS Type 10
+
+   Origin:  A european system vendor.
+
+   BIOS call support:  INT 13H AH=0xH and FDPT for BIOS drives
+   80H and 81H.
+
+   Description:  This BIOS supports drives >528MB but it does not
+   support CHS translation.  It supports only ATA drives with LBA
+   capability.  INT 13H AH=08H returns an L-CHS.  The L-CHS is
+   converted directly to an LBA.  The BIOS sets the ATA drive to
+   a P-CHS of 16 heads and 63 sectors using the Initialize Drive
+   Parameters command but it does not use this P-CHS at the ATA
+   interface.
+
+!  Support issues:  OS/2 will probably work with this BIOS as
+   long as the drive's power on default P-CHS mode uses 16 heads
+   and 63 sectors.  Because there is no EDPT, OS/2 uses the ATA
+   Identify Device power on default P-CHS, described in
+   Identify Device words 1, 3 and 6 as the current P-CHS for the
+   drive.  However, this may not represent the correct P-CHS.  A
+   newer drive will have the its current P-CHS information in
+   Identify Device words 53-58 but for some reason OS/2 does not
+   use this information.
+
+/end of part 2 of 2/
+-- 
+\\===============\\=======================\\
+ \\  Hale Landis  \\      303-548-0567     \\
+ // Niwot, CO USA // landis@sugs.tware.com //
+//===============//=======================//

src/etc/etc.i386/INSTALL.dbr

@@ -0,0 +1,467 @@
+           How It Works -- DOS Floppy Disk Boot Sector
+
+                           Version 1a
+
+             by Hale Landis (landis@sugs.tware.com)
+
+
+THE "HOW IT WORKS" SERIES
+
+This is one of several How It Works documents.  The series
+currently includes the following:
+
+* How It Works -- CHS Translation
+* How It Works -- Master Boot Record
+* How It Works -- DOS Floppy Boot Sector
+* How It Works -- OS2 Boot Sector
+* How It Works -- Partition Tables
+
+
+DOS FLOPPY DISK BOOT SECTOR
+
+This article is a disassembly of a floppy disk boot sector for a
+DOS floppy.  The boot sector of a floppy disk is located at
+cylinder 0, head 0, sector 1. This sector is created by a floppy
+disk formating program, such as the DOS FORMAT program.  The boot
+sector of a FAT hard disk partition has a similar layout and
+function.  Basically a bootable FAT hard disk partition looks
+like a big floppy during the early stages of the system's boot
+processing.
+
+At the completion of your system's Power On Self Test (POST), INT
+19 is called.  Usually INT 19 tries to read a boot sector from
+the first floppy drive.  If a boot sector is found on the floppy
+disk, the that boot sector is read into memory at location
+0000:7C00 and INT 19 jumps to memory location 0000:7C00.
+However, if no boot sector is found on the first floppy drive,
+INT 19 tries to read the MBR from the first hard drive.  If an
+MBR is found it is read into memory at location 0000:7c00 and INT
+19 jumps to memory location 0000:7c00.  The small program in the
+MBR will attempt to locate an active (bootable) partition in its
+partition table.  If such a partition is found, the boot sector
+of that partition is read into memory at location 0000:7C00 and
+the MBR program jumps to memory location 0000:7C00.  Each
+operating system has its own boot sector format.  The small
+program in the boot sector must locate the first part of the
+operating system's kernel loader program (or perhaps the kernel
+itself or perhaps a "boot manager program") and read that into
+memory.
+
+INT 19 is also called when the CTRL-ALT-DEL keys are used.  On
+most systems, CTRL-ALT-DEL causes an short version of the POST to
+be executed before INT 19 is called.
+
+=====
+
+Where stuff is:
+
+   The BIOS Parameter Block (BPB) starts at offset 0.
+   The boot sector program starts at offset 3e.
+   The messages issued by this program start at offset 19e.
+   The DOS hidden file names start at offset 1e6.
+   The boot sector signature is at offset 1fe.
+
+Here is a summary of what this thing does:
+
+1) Copy Diskette Parameter Table which is pointed to by INT 1E.
+2) Alter the copy of the Diskette Parameter Table.
+3) Alter INT 1E to point to altered Diskette Parameter Table.
+4) Do INT 13 AH=00, disk reset call.
+5) Compute sector address of root directory.
+6) Read first sector of root directory into 0000:0500.
+7) Confirm that first two directory entries are for IO.SYS
+   and MSDOS.SYS.
+8) Read first 3 sectors of IO.SYS into 0000:0700 (or 0070:0000).
+9) Leave some information in the registers and jump to
+   IO.SYS at 0070:0000.
+
+NOTE:
+
+   This program uses the CHS based INT 13H AH=02 to read the FAT
+   root directory and to read the IO.SYS file.  If the drive is
+   >528MB, this CHS must be a translated CHS (or L-CHS, see my
+   BIOS TYPES document).  Except for internal computations no
+   addresses in LBA form are used, another reason why LBA doesn't
+   solve the >528MB problem.
+
+=====
+
+Here is the entire sector in hex and ascii.
+
+OFFSET 0 1 2 3  4 5 6 7  8 9 A B  C D E F  *0123456789ABCDEF*
+000000 eb3c904d 53444f53 352e3000 02010100 *.<.MSDOS5.0.....*
+000010 02e00040 0bf00900 12000200 00000000 *...@............*
+000020 00000000 0000295a 5418264e 4f204e41 *......)ZT.&NO NA*
+000030 4d452020 20204641 54313220 2020fa33 *ME    FAT12   .3*
+000040 c08ed0bc 007c1607 bb780036 c5371e56 *.....|...x.6.7.V*
+000050 1653bf3e 7cb90b00 fcf3a406 1fc645fe *.S.>|.........E.*
+000060 0f8b0e18 7c884df9 894702c7 073e7cfb *....|.M..G...>|.*
+000070 cd137279 33c03906 137c7408 8b0e137c *..ry3.9..|t....|*
+000080 890e207c a0107cf7 26167c03 061c7c13 *.. |..|.&.|...|.*
+000090 161e7c03 060e7c83 d200a350 7c891652 *..|...|....P|..R*
+0000a0 7ca3497c 89164b7c b82000f7 26117c8b *|.I|..K|. ..&.|.*
+0000b0 1e0b7c03 c348f7f3 0106497c 83164b7c *..|..H....I|..K|*
+0000c0 00bb0005 8b16527c a1507ce8 9200721d *......R|.P|...r.*
+0000d0 b001e8ac 0072168b fbb90b00 bee67df3 *.....r........}.*
+0000e0 a6750a8d 7f20b90b 00f3a674 18be9e7d *.u... .....t...}*
+0000f0 e85f0033 c0cd165e 1f8f048f 4402cd19 *._.3...^....D...*
+000100 585858eb e88b471a 48488a1e 0d7c32ff *XXX...G.HH...|2.*
+000110 f7e30306 497c1316 4b7cbb00 07b90300 *....I|..K|......*
+000120 505251e8 3a0072d8 b001e854 00595a58 *PRQ.:.r....T.YZX*
+000130 72bb0501 0083d200 031e0b7c e2e28a2e *r..........|....*
+000140 157c8a16 247c8b1e 497ca14b 7cea0000 *.|..$|..I|.K|...*
+000150 7000ac0a c07429b4 0ebb0700 cd10ebf2 *p....t).........*
+000160 3b16187c 7319f736 187cfec2 88164f7c *;..|s..6.|....O|*
+000170 33d2f736 1a7c8816 257ca34d 7cf8c3f9 *3..6.|..%|.M|...*
+000180 c3b4028b 164d7cb1 06d2e60a 364f7c8b *.....M|.....6O|.*
+000190 ca86e98a 16247c8a 36257ccd 13c30d0a *.....$|.6%|.....*
+0001a0 4e6f6e2d 53797374 656d2064 69736b20 *Non-System disk *
+0001b0 6f722064 69736b20 6572726f 720d0a52 *or disk error..R*
+0001c0 65706c61 63652061 6e642070 72657373 *eplace and press*
+0001d0 20616e79 206b6579 20776865 6e207265 * any key when re*
+0001e0 6164790d 0a00494f 20202020 20205359 *ady...IO      SY*
+0001f0 534d5344 4f532020 20535953 000055aa *SMSDOS   SYS..U.*
+
+=====
+
+The first 62 bytes of a boot sector are known as the BIOS
+Parameter Block (BPB).  Here is the layout of the BPB fields
+and the values they are assigned in this boot sector:
+
+   db JMP instruction      at 7c00 size  2 = eb3c
+   db NOP instruction         7c02       1   90
+   db OEMname                 7c03       8   'MSDOS5.0'
+   dw bytesPerSector          7c0b       2   0200
+   db sectPerCluster          7c0d       1   01
+   dw reservedSectors         7c0e       2   0001
+   db numFAT                  7c10       1   02
+   dw numRootDirEntries       7c11       2   00e0
+   dw numSectors              7c13       2   0b40 (ignore numSectorsHuge)
+   db mediaType               7c15       1   f0
+   dw numFATsectors           7c16       2   0009
+   dw sectorsPerTrack         7c18       2   0012
+   dw numHeads                7c1a       2   0002
+   dd numHiddenSectors        7c1c       4   00000000
+   dd numSectorsHuge          7c20       4   00000000
+   db driveNum                7c24       1   00
+   db reserved                7c25       1   00
+   db signature               7c26       1   29
+   dd volumeID                7c27       4   5a541826
+   db volumeLabel             7c2b      11   'NO NAME   '
+   db fileSysType             7c36       8   'FAT12   '
+
+=====
+
+Here is the boot sector...
+
+The first 3 bytes of the BPB are JMP and NOP instructions.
+
+0000:7C00 EB3C        JMP     START
+0000:7C02 90          NOP
+
+Here is the rest of the BPB.
+
+0000:7C00 ......4d 53444f53 352e3000 02010100 *   MSDOS5.0.....*
+0000:7C10 02e00040 0bf00900 12000200 00000000 *...@............*
+0000:7C20 00000000 0000295a 5418264e 4f204e41 *......)ZT.&NO NA*
+0000:7C30 4d452020 20204641 54313220 2020.... *ME    FAT12     *
+
+Now pay attention here...
+
+   The 11 bytes starting at 0000:7c3e are immediately overlaid by
+   information copied from another part of memory.  That
+   information is the Diskette Parameter Table.  This data is
+   pointed to by INT 1E.  This data is:
+
+   7c3e = Step rate and head unload time.
+   7c3f = Head load time and DMA mode flag.
+   7c40 = Delay for motor turn off.
+   7c41 = Bytes per sector.
+   7c42 = Sectors per track.
+   7c43 = Intersector gap length.
+   7c44 = Data length.
+   7c45 = Intersector gap length during format.
+   7c46 = Format byte value.
+   7c47 = Head settling time.
+   7c48 = Delay until motor at normal speed.
+
+   The 11 bytes starting at 0000:7c49 are also overlaid by the
+   following data:
+
+   7c49 - 7c4c = diskette sector address (as LBA)
+                    of the data area.
+   7c4d - 7c4e = cylinder number to read from.
+   7c4f - 7c4f = sector number to read from.
+   7c50 - 7c53 = diskette sector address (as LBA)
+                    of the root directory.
+
+               START:                        START OF BOOT SECTOR PROGRAM
+
+0000:7C3E FA          CLI                          interrupts off
+0000:7C3F 33C0        XOR     AX,AX                set AX to zero
+0000:7C41 8ED0        MOV     SS,AX                SS is now zero
+0000:7C43 BC007C      MOV     SP,7C00              SP is now 7c00
+0000:7C46 16          PUSH    SS                   also set ES
+0000:7C47 07          POP     ES                      to zero
+
+                              The INT 1E vector is at 0000:0078.
+                              Get the address that the vector points to
+                              into the DS:SI registers.
+
+0000:7C48 BB7800      MOV     BX,0078              BX is now 78
+0000:7C4B 36          SS:
+0000:7C4C C537        LDS     SI,[BX]              DS:SI is now [0:78]
+0000:7C4E 1E          PUSH    DS                   save DS:SI --
+0000:7C4F 56          PUSH    SI                      saves param tbl addr
+0000:7C50 16          PUSH    SS                   save SS:BX --
+0000:7C51 53          PUSH    BX                      saves INT 1E address
+
+                              Move the diskette param table to 0000:7c3e.
+
+0000:7C52 BF3E7C      MOV     DI,7C3E              DI is address of START
+0000:7C55 B90B00      MOV     CX,000B              count is 11
+0000:7C58 FC          CLD                          clear direction
+0000:7C59 F3          REPZ                         move the diskette param
+0000:7C5A A4          MOVSB                           table to 0000:7c3e
+0000:7C5B 06          PUSH    ES                   also set DS
+0000:7C5C 1F          POP     DS                      to zero
+
+                              Alter some of the diskette param table data.
+
+0000:7C5D C645FE0F    MOV     BYTE PTR [DI-02],0F  change head settle time
+                                                      at 0000:7c47
+0000:7C61 8B0E187C    MOV     CX,[7C18]            sectors per track
+0000:7C65 884DF9      MOV     [DI-07],CL              save at 0000:7c42
+
+                              Change INT 1E so that it points to the
+                              altered Diskette param table at 0000:7c3e.
+
+0000:7C68 894702      MOV     [BX+02],AX           change INT 1E segment
+0000:7C6B C7073E7C    MOV     WORD PTR [BX],7C3E   change INT 1E offset
+
+                              Call INT 13 with AX=0000, disk reset, so
+                              that the new diskette param table is used.
+
+0000:7C6F FB          STI                          interrupts on
+0000:7C70 CD13        INT     13                   do diskette reset call
+0000:7C72 7279        JB      TALK                 jmp if any error
+
+                              Detemine the starting sector address of
+                              the root directory as an LBA.
+
+0000:7C74 33C0        XOR     AX,AX                AX is now zero
+0000:7C76 3906137C    CMP     [7C13],AX            number sectros zero?
+0000:7C7A 7408        JZ      SMALL_DISK           yes
+0000:7C7C 8B0E137C    MOV     CX,[7C13]            number of sectors
+0000:7C80 890E207C    MOV     [7C20],CX            save in huge num sects
+
+         SMALL_DISK:
+
+0000:7C84 A0107C      MOV     AL,[7C10]            number of FAT tables
+0000:7C87 F726167C    MUL     WORD PTR [7C16]      number of fat sectors
+0000:7C8B 03061C7C    ADD     AX,[7C1C]            number of hidden sectors
+0000:7C8F 13161E7C    ADC     DX,[7C1E]            number of hidden sectors
+0000:7C93 03060E7C    ADD     AX,[7C0E]            number of reserved sectors
+0000:7C97 83D200      ADC     DX,+00               number of reserved sectors
+0000:7C9A A3507C      MOV     [7C50],AX            save start addr
+0000:7C9D 8916527C    MOV     [7C52],DX               of root dir (as LBA)
+0000:7CA1 A3497C      MOV     [7C49],AX            save start addr
+0000:7CA4 89164B7C    MOV     [7C4B],DX               of root dir (as LBA)
+
+                              Determine sector address of first sector
+                              in the data area as an LBA.
+
+0000:7CA8 B82000      MOV     AX,0020              size of a dir entry (32)
+0000:7CAB F726117C    MUL     WORD PTR [7C11]      number of root dir entries
+0000:7CAF 8B1E0B7C    MOV     BX,[7C0B]            bytes per sector
+0000:7CB3 03C3        ADD     AX,BX
+0000:7CB5 48          DEC     AX
+0000:7CB6 F7F3        DIV     BX
+0000:7CB8 0106497C    ADD     [7C49],AX            add to start addr
+0000:7CBC 83164B7C00  ADC     WORD PTR [7C4B],+00     of root dir (as LBA)
+
+                              Read the first root dir sector into 0000:0500.
+
+0000:7CC1 BB0005      MOV     BX,0500              addr to read into
+0000:7CC4 8B16527C    MOV     DX,[7C52]            get start of address
+0000:7CC8 A1507C      MOV     AX,[7C50]               of root dir (as LBA)
+0000:7CCB E89200      CALL    CONVERT              call conversion routine
+0000:7CCE 721D        JB      TALK                 jmp is any error
+0000:7CD0 B001        MOV     AL,01                read 1 sector
+0000:7CD2 E8AC00      CALL    READ_SECTORS         read 1st root dir sector
+0000:7CD5 7216        JB      TALK                 jmp if any error
+0000:7CD7 8BFB        MOV     DI,BX                addr of 1st dir entry
+0000:7CD9 B90B00      MOV     CX,000B              count is 11
+0000:7CDC BEE67D      MOV     SI,7DE6              addr of file names
+0000:7CDF F3          REPZ                         is this "IO.SYS"?
+0000:7CE0 A6          CMPSB
+0000:7CE1 750A        JNZ     TALK                 no
+0000:7CE3 8D7F20      LEA     DI,[BX+20]           addr of next dir entry
+0000:7CE6 B90B00      MOV     CX,000B              count is 11
+0000:7CE9 F3          REPZ                         is this "MSDOS.SYS"?
+0000:7CEA A6          CMPSB
+0000:7CEB 7418        JZ      FOUND_FILES          they are equal
+
+               TALK:
+
+                              Display "Non-System disk..." message,
+                              wait for user to hit a key, restore
+                              the INT 1E vector and then
+                              call INT 19 to start boot processing
+                              all over again.
+
+0000:7CED BE9E7D      MOV     SI,7D9E              "Non-System disk..."
+0000:7CF0 E85F00      CALL    MSG_LOOP             display message
+0000:7CF3 33C0        XOR     AX,AX                INT 16 function
+0000:7CF5 CD16        INT     16                   read keyboard
+0000:7CF7 5E          POP     SI                   get INT 1E vector's
+0000:7CF8 1F          POP     DS                      address
+0000:7CF9 8F04        POP     [SI]                 restore the INT 1E
+0000:7CFB 8F4402      POP     [SI+02]                 vector's data
+0000:7CFE CD19        INT     19                   CALL INT 19 to try again
+
+         SETUP_TALK:
+
+0000:7D00 58          POP     AX                   pop junk off stack
+0000:7D01 58          POP     AX                   pop junk off stack
+0000:7D02 58          POP     AX                   pop junk off stack
+0000:7D03 EBE8        JMP     TALK                 now talk to the user
+
+        FOUND_FILES:
+
+                              Compute the sector address of the first
+                              sector of IO.SYS.
+
+0000:7D05 8B471A      MOV     AX,[BX+1A]           get starting cluster num
+0000:7D08 48          DEC     AX                   subtract 1
+0000:7D09 48          DEC     AX                   subtract 1
+0000:7D0A 8A1E0D7C    MOV     BL,[7C0D]            sectors per cluster
+0000:7D0E 32FF        XOR     BH,BH
+0000:7D10 F7E3        MUL     BX                   multiply
+0000:7D12 0306497C    ADD     AX,[7C49]            add start addr of
+0000:7D16 13164B7C    ADC     DX,[7C4B]               root dir (as LBA)
+
+                              Read IO.SYS into memory at 0000:0700.  IO.SYS
+                              is 3 sectors long.
+
+0000:7D1A BB0007      MOV     BX,0700              address to read into
+0000:7D1D B90300      MOV     CX,0003              read 3 sectors
+
+          READ_LOOP:
+
+                              Read the first 3 sectors of IO.SYS
+                              (IO.SYS is much longer than 3 sectors).
+
+0000:7D20 50          PUSH    AX                   save AX
+0000:7D21 52          PUSH    DX                   save DX
+0000:7D22 51          PUSH    CX                   save CX
+0000:7D23 E83A00      CALL    CONVERT              call conversion routine
+0000:7D26 72D8        JB      SETUP_TALK           jmp if error
+0000:7D28 B001        MOV     AL,01                read one sector
+0000:7D2A E85400      CALL    READ_SECTORS         read one sector
+0000:7D2D 59          POP     CX                   restore CX
+0000:7D2E 5A          POP     DX                   restore DX
+0000:7D2F 58          POP     AX                   restore AX
+0000:7D30 72BB        JB      TALK                 jmp if any INT 13 error
+0000:7D32 050100      ADD     AX,0001              add one to the sector addr
+0000:7D35 83D200      ADC     DX,+00               add one to the sector addr
+0000:7D38 031E0B7C    ADD     BX,[7C0B]            incr mem addr by sect size
+0000:7D3C E2E2        LOOP    READ_LOOP            read next sector
+
+                              Leave information in the AX, BX, CX and DX
+                              registers for IO.SYS to use.  Finally,
+                              jump to IO.SYS at 0070:0000.
+
+0000:7D3E 8A2E157C    MOV     CH,[7C15]            media type
+0000:7D42 8A16247C    MOV     DL,[7C24]            drive number
+0000:7D46 8B1E497C    MOV     BX,[7C49]            get start addr of
+0000:7D4A A14B7C      MOV     AX,[7C4B]               root dir (as LBA)
+0000:7D4D EA00007000  JMP     0070:0000            JUMP TO 0070:0000
+
+               MSG_LOOP:
+
+                              This routine displays a message using
+                              INT 10 one character at a time.
+                              The message address is in DS:SI.
+
+0000:7D52 AC          LODSB                        get message character
+0000:7D53 0AC0        OR      AL,AL                end of message?
+0000:7D55 7429        JZ      RETURN               jmp if yes
+0000:7D57 B40E        MOV     AH,0E                display one character
+0000:7D59 BB0700      MOV     BX,0007              video attrbiutes
+0000:7D5C CD10        INT     10                   display one character
+0000:7D5E EBF2        JMP     MSG_LOOP             do again
+
+            CONVERT:
+                              This routine
+                              converts a sector address (an LBA) to
+                              a CHS address.  The LBA is in DX:AX.
+
+0000:7D60 3B16187C    CMP     DX,[7C18]            hi part of LBA > sectPerTrk?
+0000:7D64 7319        JNB     SET_CARRY            jmp if yes
+0000:7D66 F736187C    DIV     WORD PTR [7C18]      div by sectors per track
+0000:7D6A FEC2        INC     DL                   add 1 to sector number
+0000:7D6C 88164F7C    MOV     [7C4F],DL            save sector number
+0000:7D70 33D2        XOR     DX,DX                zero DX
+0000:7D72 F7361A7C    DIV     WORD PTR [7C1A]      div number of heads
+0000:7D76 8816257C    MOV     [7C25],DL            save head number
+0000:7D7A A34D7C      MOV     [7C4D],AX            save cylinder number
+0000:7D7D F8          CLC                          clear carry
+0000:7D7E C3          RET                          return
+
+          SET_CARRY:
+
+0000:7D7F F9          STC                          set carry
+
+             RETURN:
+
+0000:7D80 C3          RET                          return
+
+       READ_SECTORS:
+
+                              The caller of this routine supplies:
+                                 AL = number of sectors to read
+                                 ES:BX = memory location to read into
+                                 and CHS address to read from in
+                                 memory locations 7c25 and 7C4d-7c4f.
+
+0000:7D81 B402        MOV     AH,02                INT 13 read sectors
+0000:7D83 8B164D7C    MOV     DX,[7C4D]            get cylinder number
+0000:7D87 B106        MOV     CL,06                shift count
+0000:7D89 D2E6        SHL     DH,CL                shift upper cyl left 6 bits
+0000:7D8B 0A364F7C    OR      DH,[7C4F]            or in sector number
+0000:7D8F 8BCA        MOV     CX,DX                move to CX
+0000:7D91 86E9        XCHG    CH,CL                CH=cyl lo, CL=cyl hi + sect
+0000:7D93 8A16247C    MOV     DL,[7C24]            drive number
+0000:7D97 8A36257C    MOV     DH,[7C25]            head number
+0000:7D9B CD13        INT     13                   read sectors
+0000:7D9D C3          RET                          return
+
+Data not used.
+
+0000:7D90 ca86e98a 16247c8a 36257ccd 13c3.... *.....$|.6%|...  *
+
+Messages here.
+
+0000:7D90 ........ ........ ........ ....0d0a *              ..*
+0000:7Da0 4e6f6e2d 53797374 656d2064 69736b20 *Non-System disk *
+0000:7Db0 6f722064 69736b20 6572726f 720d0a52 *or disk error..R*
+0000:7Dc0 65706c61 63652061 6e642070 72657373 *eplace and press*
+0000:7Dd0 20616e79 206b6579 20776865 6e207265 * any key when re*
+0000:7De0 6164790d 0a00.... ........ ........ *ady...          *
+
+MS DOS hidden file names (first two root directory entries).
+
+0000:7De0 ........ ....494f 20202020 20205359 *      IO      SY*
+0000:7Df0 534d5344 4f532020 20535953 000055aa *SMSDOS   SYS..U.*
+
+The last two bytes contain a 55AAH signature.
+
+0000:7Df0 ........ ........ ........ ....55aa *              U.*
+
+/end/
+-- 
+\\===============\\=======================\\
+ \\  Hale Landis  \\      303-548-0567     \\
+ // Niwot, CO USA // landis@sugs.tware.com //
+//===============//=======================//

src/etc/etc.i386/INSTALL.mbr

@@ -0,0 +1,271 @@
+               How It Works -- Master Boot Record
+
+                           Version 1a
+
+             by Hale Landis (landis@sugs.tware.com)
+
+
+THE "HOW IT WORKS" SERIES
+
+This is one of several How It Works documents.  The series
+currently includes the following:
+
+* How It Works -- CHS Translation
+* How It Works -- Master Boot Record
+* How It Works -- DOS Floppy Boot Sector
+* How It Works -- OS2 Boot Sector
+* How It Works -- Partition Tables
+
+
+MASTER BOOT RECORD
+
+This article is a disassembly of a Master Boot Record (MBR).  The
+MBR is the sector at cylinder 0, head 0, sector 1 of a hard disk.
+An MBR is created by the FDISK program.  The FDISK program of all
+operating systems must create a functionally similar MBR. The MBR
+is first of what could be many partition sectors, each one
+containing a four entry partition table.
+
+At the completion of your system's Power On Self Test (POST), INT
+19 is called.  Usually INT 19 tries to read a boot sector from
+the first floppy drive.  If a boot sector is found on the floppy
+disk, the that boot sector is read into memory at location
+0000:7C00 and INT 19 jumps to memory location 0000:7C00.
+However, if no boot sector is found on the first floppy drive,
+INT 19 tries to read the MBR from the first hard drive.  If an
+MBR is found it is read into memory at location 0000:7c00 and INT
+19 jumps to memory location 0000:7c00.  The small program in the
+MBR will attempt to locate an active (bootable) partition in its
+partition table.  If such a partition is found, the boot sector
+of that partition is read into memory at location 0000:7C00 and
+the MBR program jumps to memory location 0000:7C00.  Each
+operating system has its own boot sector format.  The small
+program in the boot sector must locate the first part of the
+operating system's kernel loader program (or perhaps the kernel
+itself or perhaps a "boot manager program") and read that into
+memory.
+
+INT 19 is also called when the CTRL-ALT-DEL keys are used.  On
+most systems, CTRL-ALT-DEL causes an short version of the POST to
+be executed before INT 19 is called.
+
+=====
+
+Where stuff is:
+
+   The MBR program code starts at offset 0000.
+   The MBR messages start at offset 008b.
+   The partition table starts at offset 00be.
+   The signature is at offset 00fe.
+
+Here is a summary of what this thing does:
+
+   If an active partition is found, that partition's boot record
+   is read into 0000:7c00 and the MBR code jumps to 0000:7c00
+   with SI pointing to the partition table entry that describes
+   the partition being booted.  The boot record program uses this
+   data to determine the drive being booted from and the location
+   of the partition on the disk.
+
+   If no active partition table enty is found, ROM BASIC is
+   entered via INT 18.  All other errors cause a system hang, see
+   label HANG.
+
+NOTES (VERY IMPORTANT):
+
+   1) The first byte of an active partition table entry is 80.
+   This byte is loaded into the DL register before INT 13 is
+   called to read the boot sector.  When INT 13 is called, DL is
+   the BIOS device number.  Because of this, the boot sector read
+   by this MBR program can only be read from BIOS device number
+   80 (the first hard disk).  This is one of the reasons why it
+   is usually not possible to boot from any other hard disk.
+
+   2) The MBR program uses the CHS based INT 13H AH=02H call to
+   read the boot sector of the active partition.  The location of
+   the active partition's boot sector is in the partition table
+   entry in CHS format.  If the drive is >528MB, this CHS must be
+   a translated CHS (or L-CHS, see my BIOS TYPES document).
+   No addresses in LBA form are used (another reason why LBA
+   doesn't solve the >528MB problem).
+
+=====
+
+Here is the entire MBR record (hex dump and ascii).
+
+OFFSET 0 1 2 3  4 5 6 7  8 9 A B  C D E F  *0123456789ABCDEF*
+000000 fa33c08e d0bc007c 8bf45007 501ffbfc *.3.....|..P.P...*
+000010 bf0006b9 0001f2a5 ea1d0600 00bebe07 *................*
+000020 b304803c 80740e80 3c00751c 83c610fe *...<.t..<.u.....*
+000030 cb75efcd 188b148b 4c028bee 83c610fe *.u......L.......*
+000040 cb741a80 3c0074f4 be8b06ac 3c00740b *.t..<.t.....<.t.*
+000050 56bb0700 b40ecd10 5eebf0eb febf0500 *V.......^.......*
+000060 bb007cb8 010257cd 135f730c 33c0cd13 *..|...W.._s.3...*
+000070 4f75edbe a306ebd3 bec206bf fe7d813d *Ou...........}.=*
+000080 55aa75c7 8bf5ea00 7c000049 6e76616c *U.u.....|..Inval*
+000090 69642070 61727469 74696f6e 20746162 *id partition tab*
+0000a0 6c650045 72726f72 206c6f61 64696e67 *le.Error loading*
+0000b0 206f7065 72617469 6e672073 79737465 * operating syste*
+0000c0 6d004d69 7373696e 67206f70 65726174 *m.Missing operat*
+0000d0 696e6720 73797374 656d0000 00000000 *ing system......*
+0000e0 00000000 00000000 00000000 00000000 *................*
+0000f0 TO 0001af SAME AS ABOVE
+0001b0 00000000 00000000 00000000 00008001 *................*
+0001c0 0100060d fef83e00 00000678 0d000000 *......>....x....*
+0001d0 00000000 00000000 00000000 00000000 *................*
+0001e0 00000000 00000000 00000000 00000000 *................*
+0001f0 00000000 00000000 00000000 000055aa *..............U.*
+
+=====
+
+Here is the disassembly of the MBR...
+
+This sector is initially loaded into memory at 0000:7c00 but
+it immediately relocates itself to 0000:0600.
+
+                 BEGIN:                      NOW AT 0000:7C00, RELOCATE
+
+0000:7C00 FA            CLI                     disable int's
+0000:7C01 33C0          XOR     AX,AX           set stack seg to 0000
+0000:7C03 8ED0          MOV     SS,AX
+0000:7C05 BC007C        MOV     SP,7C00         set stack ptr to 7c00
+0000:7C08 8BF4          MOV     SI,SP           SI now 7c00
+0000:7C0A 50            PUSH    AX
+0000:7C0B 07            POP     ES              ES now 0000:7c00
+0000:7C0C 50            PUSH    AX
+0000:7C0D 1F            POP     DS              DS now 0000:7c00
+0000:7C0E FB            STI                     allow int's
+0000:7C0F FC            CLD                     clear direction
+0000:7C10 BF0006        MOV     DI,0600         DI now 0600
+0000:7C13 B90001        MOV     CX,0100         move 256 words (512 bytes)
+0000:7C16 F2            REPNZ                   move MBR from 0000:7c00
+0000:7C17 A5            MOVSW                      to 0000:0600
+0000:7C18 EA1D060000    JMP     0000:061D       jmp to NEW_LOCATION
+
+        NEW_LOCATION:                        NOW AT 0000:0600
+
+0000:061D BEBE07      MOV     SI,07BE           point to first table entry
+0000:0620 B304        MOV     BL,04             there are 4 table entries
+
+        SEARCH_LOOP1:                        SEARCH FOR AN ACTIVE ENTRY
+
+0000:0622 803C80      CMP     BYTE PTR [SI],80  is this the active entry?
+0000:0625 740E        JZ      FOUND_ACTIVE      yes
+0000:0627 803C00      CMP     BYTE PTR [SI],00  is this an inactive entry?
+0000:062A 751C        JNZ     NOT_ACTIVE        no
+0000:062C 83C610      ADD     SI,+10            incr table ptr by 16
+0000:062F FECB        DEC     BL                decr count
+0000:0631 75EF        JNZ     SEARCH_LOOP1      jmp if not end of table
+0000:0633 CD18        INT     18                GO TO ROM BASIC
+
+        FOUND_ACTIVE:                        FOUND THE ACTIVE ENTRY
+
+0000:0635 8B14        MOV     DX,[SI]           set DH/DL for INT 13 call
+0000:0637 8B4C02      MOV     CX,[SI+02]        set CH/CL for INT 13 call
+0000:063A 8BEE        MOV     BP,SI             save table ptr
+
+        SEARCH_LOOP2:                        MAKE SURE ONLY ONE ACTIVE ENTRY
+
+0000:063C 83C610      ADD     SI,+10            incr table ptr by 16
+0000:063F FECB        DEC     BL                decr count
+0000:0641 741A        JZ      READ_BOOT         jmp if end of table
+0000:0643 803C00      CMP     BYTE PTR [SI],00  is this an inactive entry?
+0000:0646 74F4        JZ      SEARCH_LOOP2      yes
+
+          NOT_ACTIVE:                        MORE THAN ONE ACTIVE ENTRY FOUND
+
+0000:0648 BE8B06      MOV     SI,068B           display "Invld prttn tbl"
+
+         DISPLAY_MSG:                        DISPLAY MESSAGE LOOP
+
+0000:064B AC          LODSB                     get char of message
+0000:064C 3C00        CMP     AL,00             end of message
+0000:064E 740B        JZ      HANG              yes
+0000:0650 56          PUSH    SI                save SI
+0000:0651 BB0700      MOV     BX,0007           screen attributes
+0000:0654 B40E        MOV     AH,0E             output 1 char of message
+0000:0656 CD10        INT     10                   to the display
+0000:0658 5E          POP     SI                restore SI
+0000:0659 EBF0        JMP     DISPLAY_MSG       do it again
+
+                HANG:                        HANG THE SYSTEM LOOP
+
+0000:065B EBFE        JMP     HANG              sit and stay!
+
+           READ_BOOT:                        READ ACTIVE PARITION BOOT RECORD
+
+0000:065D BF0500      MOV     DI,0005           INT 13 retry count
+
+           INT13RTRY:                        INT 13 RETRY LOOP
+
+0000:0660 BB007C      MOV     BX,7C00
+0000:0663 B80102      MOV     AX,0201           read 1 sector
+0000:0666 57          PUSH    DI                save DI
+0000:0667 CD13        INT     13                read sector into 0000:7c00
+0000:0669 5F          POP     DI                restore DI
+0000:066A 730C        JNB     INT13OK           jmp if no INT 13
+0000:066C 33C0        XOR     AX,AX             call INT 13 and
+0000:066E CD13        INT     13                   do disk reset
+0000:0670 4F          DEC     DI                decr DI
+0000:0671 75ED        JNZ     INT13RTRY         if not zero, try again
+0000:0673 BEA306      MOV     SI,06A3           display "Errr ldng systm"
+0000:0676 EBD3        JMP     DISPLAY_MSG       jmp to display loop
+
+             INT13OK:                        INT 13 ERROR
+
+0000:0678 BEC206      MOV     SI,06C2              "missing op sys"
+0000:067B BFFE7D      MOV     DI,7DFE              point to signature
+0000:067E 813D55AA    CMP     WORD PTR [DI],AA55   is signature correct?
+0000:0682 75C7        JNZ     DISPLAY_MSG          no
+0000:0684 8BF5        MOV     SI,BP                set SI
+0000:0686 EA007C0000  JMP     0000:7C00            JUMP TO THE BOOT SECTOR
+                                                      WITH SI POINTING TO
+                                                      PART TABLE ENTRY
+
+Messages here.
+
+0000:0680 ........ ........ ......49 6e76616c *           Inval*
+0000:0690 69642070 61727469 74696f6e 20746162 *id partition tab*
+0000:06a0 6c650045 72726f72 206c6f61 64696e67 *le.Error loading*
+0000:06b0 206f7065 72617469 6e672073 79737465 * operating syste*
+0000:06c0 6d004d69 7373696e 67206f70 65726174 *m.Missing operat*
+0000:06d0 696e6720 73797374 656d00.. ........ *ing system.     *
+
+Data not used.
+
+0000:06d0 ........ ........ ......00 00000000 *           .....*
+0000:06e0 00000000 00000000 00000000 00000000 *................*
+0000:06f0 00000000 00000000 00000000 00000000 *................*
+0000:0700 00000000 00000000 00000000 00000000 *................*
+0000:0710 00000000 00000000 00000000 00000000 *................*
+0000:0720 00000000 00000000 00000000 00000000 *................*
+0000:0730 00000000 00000000 00000000 00000000 *................*
+0000:0740 00000000 00000000 00000000 00000000 *................*
+0000:0750 00000000 00000000 00000000 00000000 *................*
+0000:0760 00000000 00000000 00000000 00000000 *................*
+0000:0770 00000000 00000000 00000000 00000000 *................*
+0000:0780 00000000 00000000 00000000 00000000 *................*
+0000:0790 00000000 00000000 00000000 00000000 *................*
+0000:07a0 00000000 00000000 00000000 00000000 *................*
+0000:07b0 00000000 00000000 00000000 0000.... *............    *
+
+The partition table starts at 0000:07be.  Each partition table
+entry is 16 bytes.  This table defines a single primary partition
+which is also an active (bootable) partition.
+
+0000:07b0 ........ ........ ........ ....8001 *            ....*
+0000:07c0 0100060d fef83e00 00000678 0d000000 *......>....x....*
+0000:07d0 00000000 00000000 00000000 00000000 *................*
+0000:07e0 00000000 00000000 00000000 00000000 *................*
+0000:07f0 00000000 00000000 00000000 0000.... *............    *
+
+The last two bytes contain a 55AAH signature.
+
+0000:07f0 ........ ........ ........ ....55aa *..............U.*
+
+/end/
+-- 
+\\===============\\=======================\\
+ \\  Hale Landis  \\      303-548-0567     \\
+ // Niwot, CO USA // landis@sugs.tware.com //
+//===============//=======================//

src/etc/etc.i386/INSTALL.os2br

@@ -0,0 +1,469 @@
+                How It Works -- OS2 Boot Sector
+
+                           Version 1a
+
+             by Hale Landis (landis@sugs.tware.com)
+
+
+THE "HOW IT WORKS" SERIES
+
+This is one of several How It Works documents.  The series
+currently includes the following:
+
+* How It Works -- CHS Translation
+* How It Works -- Master Boot Record
+* How It Works -- DOS Floppy Boot Sector
+* How It Works -- OS2 Boot Sector
+* How It Works -- Partition Tables
+
+
+OS2 BOOT SECTOR
+
+Note:  I'll leave it to someone else to provide you with a
+disassembly of an OS/2 HPFS boot sector, or a Linux boot sector,
+or a WinNT boot sector, etc.
+
+This article is a disassembly of a floppy or hard disk boot
+sector for OS/2.  Apparently OS/2 uses the same boot sector for
+both environments.  Basically a bootable FAT hard disk partition
+looks like a big floppy during the early stages of the system's
+boot processing.  This sector is at cylinder 0, head 0, sector 1
+of a floppy or it is the first sector within a FAT hard disk
+partition.  OS/2 floppy disk and hard disk boot sectors are
+created by the OS/2 FORMAT program.
+
+At the completion of your system's Power On Self Test (POST), INT
+19 is called.  Usually INT 19 tries to read a boot sector from
+the first floppy drive.  If a boot sector is found on the floppy
+disk, the that boot sector is read into memory at location
+0000:7C00 and INT 19 jumps to memory location 0000:7C00.
+However, if no boot sector is found on the first floppy drive,
+INT 19 tries to read the MBR from the first hard drive.  If an
+MBR is found it is read into memory at location 0000:7c00 and INT
+19 jumps to memory location 0000:7c00.  The small program in the
+MBR will attempt to locate an active (bootable) partition in its
+partition table.  If such a partition is found, the boot sector
+of that partition is read into memory at location 0000:7C00 and
+the MBR program jumps to memory location 0000:7C00.  Each
+operating system has its own boot sector format.  The small
+program in the boot sector must locate the first part of the
+operating system's kernel loader program (or perhaps the kernel
+itself or perhaps a "boot manager program") and read that into
+memory.
+
+INT 19 is also called when the CTRL-ALT-DEL keys are used.  On
+most systems, CTRL-ALT-DEL causes an short version of the POST to
+be executed before INT 19 is called.
+
+=====
+
+Where stuff is:
+
+   The BIOS Parameter Block (BPB) starts at offset 0.
+   The boot sector program starts at offset 46.
+   The messages issued by this program start at offset 198.
+   The OS/2 boot loader file name starts at offset 1d5.
+   The boot sector signature is at offset 1fe.
+
+Here is a summary of what this thing does:
+
+ 1) If booting from a hard disk partition, skip to step 6.
+ 2) Copy Diskette Parameter Table which is pointed to by INT 1E
+    to the top of memory.
+ 3) Alter the copy of the Diskette Parameter Table.
+ 4) Alter INT 1E to point to altered Diskette Parameter Table at
+    the top of memory.
+ 5) Do INT 13 AH=00, disk reset call so that the altered
+    Diskette Parameter Table is used.
+ 6) Compute sector address of the root directory.
+ 7) Read the entire root directory into memory starting at
+    location 1000:0000.
+ 8) Search the root directory entires for the file OS2BOOT.
+ 9) Read the OS2BOOT file into memory at 0800:0000.
+10) Do a far return to enter the OS2BOOT program at 0800:0000.
+
+NOTES:
+
+   This program uses the CHS based INT 13H AH=02 to read the FAT
+   root directory and to read the OS2BOOT file.  If the drive is
+   >528MB, this CHS must be a translated CHS (or L-CHS, see my
+   BIOS TYPES document).  Except for internal computations no
+   addresses in LBA form are used, another reason why LBA doesn't
+   solve the >528MB problem.
+
+=====
+
+Here is the entire sector in hex and ascii.
+
+OFFSET 0 1 2 3  4 5 6 7  8 9 A B  C D E F  *0123456789ABCDEF*
+000000 eb449049 424d2032 302e3000 02100100 *.D.IBM 20.0.....*
+000010 02000200 00f8d800 3e000e00 3e000000 *........>...>...*
+000020 06780d00 80002900 1c0c234e 4f204e41 *.x....)...#NO NA*
+000030 4d452020 20204641 54202020 20200000 *ME    FAT     ..*
+000040 00100000 0000fa33 db8ed3bc ff7bfbba *.......3.....{..*
+000050 c0078eda 803e2400 00753d1e b840008e *.....>$..u=..@..*
+000060 c026ff0e 1300cd12 c1e0068e c033ff33 *.&...........3.3*
+000070 c08ed8c5 367800fc b90b00f3 a41fa118 *....6x..........*
+000080 0026a204 001e33c0 8ed8a378 008c067a *.&....3....x...z*
+000090 001f8a16 2400cd13 a0100098 f7261600 *....$........&..*
+0000a0 03060e00 5091b820 00f72611 008b1e0b *....P.. ..&.....*
+0000b0 0003c348 f7f35003 c1a33e00 b800108e *...H..P...>.....*
+0000c0 c033ff59 890e4400 58a34200 33d2e873 *.3.Y..D.X.B.3..s*
+0000d0 0033db8b 0e11008b fb51b90b 00bed501 *.3.......Q......*
+0000e0 f3a65974 0583c320 e2ede335 268b471c *..Yt... ...5&.G.*
+0000f0 268b571e f7360b00 fec08ac8 268b571a *&.W..6......&.W.*
+000100 4a4aa00d 0032e4f7 e203063e 0083d200 *JJ...2.....>....*
+000110 bb00088e c333ff06 57e82800 8d360b00 *.....3..W.(..6..*
+000120 cbbe9801 eb03bead 01e80900 bec201e8 *................*
+000130 0300fbeb feac0ac0 7409b40e bb0700cd *........t.......*
+000140 10ebf2c3 50525103 061c0013 161e00f7 *....PRQ.........*
+000150 361800fe c28ada33 d2f7361a 008afa8b *6......3..6.....*
+000160 d0a11800 2ac34050 b402b106 d2e60af3 *....*.@P........*
+000170 8bca86e9 8a162400 8af78bdf cd1372a6 *......$.......r.*
+000180 5b598bc3 f7260b00 03f85a58 03c383d2 *[Y...&....ZX....*
+000190 002acb7f afc31200 4f532f32 20212120 *.*......OS/2 !! *
+0001a0 53595330 31343735 0d0a0012 004f532f *SYS01475.....OS/*
+0001b0 32202121 20535953 30323032 350d0a00 *2 !! SYS02025...*
+0001c0 12004f53 2f322021 21205359 53303230 *..OS/2 !! SYS020*
+0001d0 32370d0a 004f5332 424f4f54 20202020 *27...OS2BOOT    *
+0001e0 00000000 00000000 00000000 00000000 *................*
+0001f0 00000000 00000000 00000000 000055aa *..............U.*
+
+=====
+
+The first 62 bytes of a boot sector are known as the BIOS
+Parameter Block (BPB).  Here is the layout of the BPB fields
+and the values they are assigned in this boot sector:
+
+   db JMP instruction      at 7c00 size  2 = eb44
+   db NOP instruction         7c02       1   90
+   db OEMname                 7c03       8   'IBM 20.0'
+   dw bytesPerSector          7c0b       2   0200
+   db sectPerCluster          7c0d       1   01
+   dw reservedSectors         7c0e       2   0001
+   db numFAT                  7c10       1   02
+   dw numRootDirEntries       7c11       2   0200
+   dw numSectors              7c13       2   0000 (use numSectorsHuge)
+   db mediaType               7c15       1   f8
+   dw numFATsectors           7c16       2   00d8
+   dw sectorsPerTrack         7c18       2   003e
+   dw numHeads                7c1a       2   000e
+   dd numHiddenSectors        7c1c       4   00000000
+   dd numSectorsHuge          7c20       4   000d7806
+   db driveNum                7c24       1   80
+   db reserved                7c25       1   00
+   db signature               7c26       1   29
+   dd volumeID                7c27       4   001c0c23
+   db volumeLabel             7c2b      11   'NO NAME   '
+   db fileSysType             7c36       8   'FAT     '
+
+=====
+
+Here is the boot sector...
+
+The first 3 bytes of the BPB are JMP and NOP instructions.
+
+0000:7C00 EB44        JMP     START
+0000:7C02 90          NOP
+
+Here is the rest of the BPB.
+
+0000:7C00 eb449049 424d2032 302e3000 02100100 *.D.IBM 20.0.....*
+0000:7C10 02000200 00f8d800 3e000e00 3e000000 *........>...>...*
+0000:7C20 06780d00 80002900 1c0c234e 4f204e41 *.x....)...#NO NA*
+0000:7C30 4d452020 20204641 54202020 20200000 *ME    FAT     ..*
+
+Additional data areas.
+
+0000:7C30 ........ ........ ........ ....0000 *              ..*
+0000:7C40 00100000 0000.... ........ ........ *......          *
+
+   Note:
+
+   0000:7c3e (DS:003e) = number of sectors in the FATs and root dir.
+   0000:7c42 (DS:0042) = number of sectors in the FAT.
+   0000:7c44 (DS:0044) = number of sectors in the root dir.
+
+               START:                        START OF BOOT SECTOR PROGRAM
+
+0000:7C46 FA          CLI                          interrupts off
+0000:7C47 33DB        XOR     BX,BX                zero BX
+0000:7C49 8ED3        MOV     SS,BX                SS now zero
+0000:7C4B BCFF7B      MOV     SP,7BFF              SP now 7bff
+0000:7C4E FB          STI                          interrupts on
+0000:7C4F BAC007      MOV     DX,07C0              set DX to
+0000:7C52 8EDA        MOV     DS,DX                   07c0
+
+                              Are we booting from a floppy or a
+                              hard disk partition?
+
+0000:7C54 803E240000  CMP     BYTE PTR [0024],00   is driveNum in BPB 00?
+0000:7C59 753D        JNZ     NOT_FLOPPY           jmp if not zero
+
+                              We are booting from a floppy.  The
+                              Diskette Parameter Table must be
+                              copied and altered...
+
+   Diskette Parameter Table is pointed to by INT 1E.  This
+   program moves this table to high memory, alters the table, and
+   changes INT 1E to point to the altered table.
+
+   This table contains the following data:
+
+   ????:0000 = Step rate and head unload time.
+   ????:0001 = Head load time and DMA mode flag.
+   ????:0002 = Delay for motor turn off.
+   ????:0003 = Bytes per sector.
+   ????:0004 = Sectors per track.
+   ????:0005 = Intersector gap length.
+   ????:0006 = Data length.
+   ????:0007 = Intersector gap length during format.
+   ????:0008 = Format byte value.
+   ????:0009 = Head settling time.
+   ????:000a = Delay until motor at normal speed.
+
+                              Compute a valid high memory address.
+
+0000:7C5B 1E          PUSH    DS                   save DS
+0000:7C5C B84000      MOV     AX,0040              set ES
+0000:7C5F 8EC0        MOV     ES,AX                   to 0040 (BIOS data area)
+0000:7C61 26          ES:                          reduce system memory
+0000:7C62 FF0E1300    DEC     WORD PTR [0013]         size by 1024
+0000:7C66 CD12        INT     12                   get system memory size
+0000:7C68 C1E06       SHL     AX,06                shift AX (mult by 64)
+0000:7C6B 8EC0        MOV     ES,AX                move to ES
+0000:7C6D 33FF        XOR     DI,DI                zero DI
+
+                              Move the diskette param table to high memory.
+
+0000:7C6F 33C0        XOR     AX,AX                zero AX
+0000:7C71 8ED8        MOV     DS,AX                DS now zero
+0000:7C73 C5367800    LDS     SI,[0078]            DS:SI = INT 1E vector
+0000:7C77 FC          CLD                          clear direction
+0000:7C78 B90B00      MOV     CX,000B              count is 11
+0000:7C7B F3          REPZ                         copy diskette param table
+0000:7C7C A4          MOVSB                           to top of memory
+
+                              Alter the number of sectors per track
+                              in the diskette param table in high memory.
+
+0000:7C7D 1F          POP     DS                   restore DS
+0000:7C7E A11800      MOV     AX,[0018]            get sectorsPerTrack from BPB
+0000:7C81 26          ES:                          alter sectors per track
+0000:7C82 A20400      MOV     [0004],AL               in diskette param table
+
+                              Change INT 1E to point to altered diskette
+                              param table and do a INT 13 disk reset call.
+
+0000:7C85 1E          PUSH    DS                   save DS
+0000:7C86 33C0        XOR     AX,AX                AX now zero
+0000:7C88 8ED8        MOV     DS,AX                DS no zero
+0000:7C8A A37800      MOV     [0078],AX            alter INT 1E vector
+0000:7C8D 8C067A00    MOV     [007A],ES               to point to altered
+                                                      diskette param table
+0000:7C91 1F          POP     DS                   restore DS
+0000:7C92 8A162400    MOV     DL,[0024]            driveNum from BPB
+0000:7C96 CD13        INT     13                   diskette reset
+
+         NOT_FLOPPY:
+
+                              Compute the location and the size of
+                              the root directory.  Read the entire
+                              root directory into memory.
+
+0000:7C98 A01000      MOV     AL,[0010]            get numFAT
+0000:7C9B 98          CBW                          make into a word
+0000:7C9C F7261600    MUL     WORD PTR [0016]      mult by numFatSectors
+0000:7CA0 03060E00    ADD     AX,[000E]            add reservedSectors
+0000:7CA4 50          PUSH    AX                   save
+0000:7CA5 91          XCHG    CX,AX                move to CX
+0000:7CA6 B82000      MOV     AX,0020              dir entry size
+0000:7CA9 F7261100    MUL     WORD PTR [0011]      mult by numRootDirEntries
+0000:7CAD 8B1E0B00    MOV     BX,[000B]            get bytesPerSector
+0000:7CB1 03C3        ADD     AX,BX                add
+0000:7CB3 48          DEC     AX                   subtract 1
+0000:7CB4 F7F3        DIV     BX                   div by bytesPerSector
+0000:7CB6 50          PUSH    AX                   save number of dir sectors
+0000:7CB7 03C1        ADD     AX,CX                add number of fat sectors
+0000:7CB9 A33E00      MOV     [003E],AX            save
+0000:7CBC B80010      MOV     AX,1000              AX is now 1000
+0000:7CBF 8EC0        MOV     ES,AX                ES is now 1000
+0000:7CC1 33FF        XOR     DI,DI                DI is now zero
+0000:7CC3 59          POP     CX                   get number dir sectors
+0000:7CC4 890E4400    MOV     [0044],CX            save
+0000:7CC8 58          POP     AX                   get number fat sectors
+0000:7CC9 A34200      MOV     [0042],AX            save
+0000:7CCC 33D2        XOR     DX,DX                DX now zero
+0000:7CCE E87300      CALL    READ_SECTOR          read 1st sect of root dir
+0000:7CD1 33DB        XOR     BX,BX                BX is now zero
+0000:7CD3 8B0E1100    MOV     CX,[0011]            number of root dir entries
+
+         DIR_SEARCH:                         SEARCH FOR OS2BOOT.
+
+                              Search the root directory for the file
+                              name OS2BOOT.
+
+0000:7CD7 8BFB        MOV     DI,BX                DI is dir entry addr
+0000:7CD9 51          PUSH    CX                   save CX
+0000:7CDA B90B00      MOV     CX,000B              count is 11
+0000:7CDD BED501      MOV     SI,01D5              addr of "OS2BOOT"
+0000:7CE0 F3          REPZ                         is 1st dir entry
+0000:7CE1 A6          CMPSB                           for "OS2BOOT"?
+0000:7CE2 59          POP     CX                   restore CX
+0000:7CE3 7405        JZ      FOUND_OS2BOOT        jmp if OS2BOOT
+0000:7CE5 83C320      ADD     BX,+20               incr to next dir entry
+0000:7CE8 E2ED        LOOP    DIR_SEARCH           try again
+
+      FOUND_OS2BOOT:                         FOUND OS2BOOT.
+
+                              OS2BOOT was found.  Get the starting
+                              cluster number and convert to a sector
+                              address.  Read OS2BOOT into memory and
+                              finally do a far return to enter
+                              the OS2BOOT program.
+
+0000:7CEA E335        JCXZ    FAILED1              JMP if CX zero.
+0000:7CEC 26          ES:                          get the szie of
+0000:7CED 8B471C      MOV     AX,[BX+1C]              the OS2BOOT file
+0000:7CF0 26          ES:                             from the OS2BOOT
+0000:7CF1 8B571E      MOV     DX,[BX+1E]              directory entry
+0000:7CF4 F7360B00    DIV     WORD PTR [000B]      div by bytesPerSect
+0000:7CF8 FEC0        INC     AL                   add 1
+0000:7CFA 8AC8        MOV     CL,AL                num sectors OS2BOOT
+0000:7CFC 26          ES:                          get the starting
+0000:7CFD 8B571A      MOV     DX,[BX+1A]              cluster number
+0000:7D00 4A          DEC     DX                   subtract 1
+0000:7D01 4A          DEC     DX                   subtract 1
+0000:7D02 A00D00      MOV     AL,[000D]            sectorsPerCluster
+0000:7D05 32E4        XOR     AH,AH                mutiply
+0000:7D07 F7E2        MUL     DX                      to get LBA
+0000:7D09 03063E00    ADD     AX,[003E]            add number of FAT sectors
+0000:7D0D 83D200      ADC     DX,+00                  to LBA
+0000:7D10 BB0008      MOV     BX,0800              set ES
+0000:7D13 8EC3        MOV     ES,BX                   to 0800
+0000:7D15 33FF        XOR     DI,DI                set ES:DI to entry point
+0000:7D17 06          PUSH    ES                      address of
+0000:7D18 57          PUSH    DI                         OS2BOOT
+0000:7D19 E82800      CALL    READ_SECTOR          read OS2BOOT into memory
+0000:7D1C 8D360B00    LEA     SI,[000B]            set DS:SI
+0000:7D20 CB          RETF                         "far return" to OS2BOOT
+
+            FAILED1:                            OS2BOOT WAS NOT FOUND.
+
+0000:7D21 BE9801      MOV     SI,0198              "SYS01475" message
+0000:7D24 EB03        JMP     FAILED3
+
+            FAILED2:                            ERROR FROM INT 13.
+
+0000:7D26 BEAD01      MOV     SI,01AD              "SYS02025" message
+
+            FAILED3:                            OUTPUT ERROR MESSAGES.
+
+0000:7D29 E80900      CALL    MSG_LOOP             display message
+0000:7D2C BEC201      MOV     SI,01C2              "SYS02027" message
+0000:7D2F E80300      CALL    MSG_LOOP             display message
+0000:7D32 FB          STI                          interrupts on
+
+               HANG:                            HANG THE SYSTEM!
+
+0000:7D33 EBFE        JMP     HANG                 sit and stay!
+
+           MSG_LOOP:                         DISPLAY AN ERROR MESSAGE.
+
+                              Routine to display the message
+                              text pointed to by SI.
+
+0000:7D35 AC          LODSB                        get next char of message
+0000:7D36 0AC0        OR      AL,AL                end of message?
+0000:7D38 7409        JZ      RETURN               jmp if yes
+0000:7D3A B40E        MOV     AH,0E                write 1 char
+0000:7D3C BB0700      MOV     BX,0007              video attributes
+0000:7D3F CD10        INT     10                   INT 10 to write 1 char
+0000:7D41 EBF2        JMP     MSG_LOOP             do again
+
+             RETURN:
+
+0000:7D43 C3          RET                          return
+
+       READ_SECTOR:                          ROUTINE TO READ SECTORS.
+
+                              Read sectors into memory.  Read multiple
+                              sectors but don't read across a track
+                              boundary.
+
+                              The caller supplies the following:
+                                 DX:AX = sector address to read (as LBA)
+                                    CX = number of sectors to read
+                                 ES:DI = memory address to read into
+
+0000:7D44 50          PUSH    AX                   save lower part of LBA
+0000:7D45 52          PUSH    DX                   save upper part of LBA
+0000:7D46 51          PUSH    CX                   save number of sect to read
+0000:7D47 03061C00    ADD     AX,[001C]            add numHiddenSectors
+0000:7D4B 13161E00    ADC     DX,[001E]               to LBA
+0000:7D4F F7361800    DIV     WORD PTR [0018]      div by sectorsPerTrack
+0000:7D53 FEC2        INC     DL                   add 1 to sector number
+0000:7D55 8ADA        MOV     BL,DL                save sector number
+0000:7D57 33D2        XOR     DX,DX                zero upper part of LBA
+0000:7D59 F7361A00    DIV     WORD PTR [001A]      div by numHeads
+0000:7D5D 8AFA        MOV     BH,DL                save head number
+0000:7D5F 8BD0        MOV     DX,AX                save cylinder number
+0000:7D61 A11800      MOV     AX,[0018]            sectorsPerTrack
+0000:7D64 2AC3        SUB     AL,BL                sub sector number
+0000:7D66 40          INC     AX                   add 1
+0000:7D67 50          PUSH    AX                   save number of sector to read
+0000:7D68 B402        MOV     AH,02                INT 13 read sectors
+0000:7D6A B106        MOV     CL,06                shift count
+0000:7D6C D2E6        SHL     DH,CL                shift high cyl left
+0000:7D6E 0AF3        OR      DH,BL                or in sector number
+0000:7D70 8BCA        MOV     CX,DX                move cyl/sect to CX
+0000:7D72 86E9        XCHG    CH,CL                swap cyl/sect
+0000:7D74 8A162400    MOV     DL,[0024]            driveNum
+0000:7D78 8AF7        MOV     DH,BH                head number
+0000:7D7A 8BDF        MOV     BX,DI                memory addr to read into
+0000:7D7C CD13        INT     13                   INT 13 read sectors call
+0000:7D7E 72A6        JB      FAILED2              jmp if any error
+0000:7D80 5B          POP     BX                   get number of sectors read
+0000:7D81 59          POP     CX                   restore CX
+0000:7D82 8BC3        MOV     AX,BX                number of sector to AX
+0000:7D84 F7260B00    MUL     WORD PTR [000B]      multiply by sector size
+0000:7D88 03F8        ADD     DI,AX                add to memory address
+0000:7D8A 5A          POP     DX                   restore upper part of LBA
+0000:7D8B 58          POP     AX                   resotre lower part of LBA
+0000:7D8C 03C3        ADD     AX,BX                add number of sector just
+0000:7D8E 83D200      ADC     DX,+00                  read to LBA
+0000:7D91 2ACB        SUB     CL,BL                decr requested num of sect
+0000:7D93 7FAF        JG      READ_SECTOR          jmp if not zero
+0000:7D95 C3          RET                          return
+
+Data not used.
+
+0000:7D90 ........ ....1200 ........ ........ *      ..        *
+
+Messages here.
+
+0000:7D90 ........ ........ 4f532f32 20212120 *        OS/2 !! *
+0000:7Da0 53595330 31343735 0d0a0012 004f532f *SYS01475.....OS/*
+0000:7Db0 32202121 20535953 30323032 350d0a00 *2 !! SYS02025...*
+0000:7Dc0 12004f53 2f322021 21205359 53303230 *..OS/2 !! SYS020*
+0000:7Dd0 32370d0a 00...... ........ ........ *27...           *
+
+OS/2 loader file name.
+
+0000:7Dd0 ........ ..4f5332 424f4f54 20202020 *     OS2BOOT    *
+
+Data not used.
+
+0000:7De0 00000000 00000000 00000000 00000000 *................*
+0000:7Df0 00000000 00000000 00000000 0000.... *..............  *
+
+The last two bytes contain a 55AAH signature.
+
+0000:7Df0 ........ ........ ........ ....55aa *              U.*
+
+/end/
+-- 
+\\===============\\=======================\\
+ \\  Hale Landis  \\      303-548-0567     \\
+ // Niwot, CO USA // landis@sugs.tware.com //
+//===============//=======================//

src/etc/etc.i386/INSTALL.pt

@@ -0,0 +1,340 @@
+                How it Works -- Partition Tables
+
+                           Version 1c
+
+             by Hale Landis (landis@sugs.tware.com)
+
+
+THE "HOW IT WORKS" SERIES
+
+This is one of several How It Works documents.  The series
+currently includes the following:
+
+* How It Works -- CHS Translation
+* How It Works -- Master Boot Record
+* How It Works -- DOS Floppy Boot Sector
+* How It Works -- OS2 Boot Sector
+* How It Works -- Partition Tables
+
+
+PARTITION SECTOR/RECORD/TABLE BASICS
+
+FDISK creates all partition records (sectors).  The primary
+purpose of a partition record is to hold a partition table.  The
+rules for how FDISK works are unwritten but so far most FDISK
+programs (DOS, OS/2, WinNT, etc) seem to follow the same basic
+idea.
+
+First, all partition table records (sectors) have the same
+format.  This includes the partition table record at cylinder 0,
+head 0, sector 1 -- what is known as the Master Boot Record
+(MBR).  The last 66 bytes of a partition table record contain a
+partition table and a 2 byte signature.  The first 446 bytes of
+these sectors usually contain a program but only the program in
+the MBR is ever executed (so extended partition table records
+could contain something other than a program in the first 466
+bytes).  See "How It Works -- The Master Boot Record".
+
+Second, extended partitions are "nested" inside one another and
+extended partition table records form a "linked list".  I will
+attempt to show this in a diagram below.
+
+PARTITION TABLE ENTRY FORMAT
+
+Each partition table entry is 16 bytes and contains things like
+the start and end location of a partition in CHS, the start in
+LBA, the size in sectors, the partition "type" and the "active"
+flag.  Warning:  older versions of FDISK may compute incorrect
+LBA or size values.  And note:  When your computer boots itself,
+only the CHS fields of the partition table entries are used
+(another reason LBA doesn't solve the >528MB problem).  The CHS
+fields in the partition tables are in L-CHS format -- see "How It
+Works -- CHS Translation".
+
+There is no central clearing house to assign the codes used in
+the one byte "type" field.  But codes are assigned (or used) to
+define most every type of file system that anyone has ever
+implemented on the x86 PC:  12-bit FAT, 16-bit FAT, HPFS, NTFS,
+etc.  Plus, an extended partition also has a unique type code.
+
+Note:  I know of no complete list of all the type codes that have
+been used to date.  However, I try to include such a list in a
+future version of this document.
+
+The 16 bytes of a partition table entry are used as follows:
+
+    +--- Bit 7 is the active partition flag, bits 6-0 are zero.
+    |
+    |    +--- Starting CHS in INT 13 call format.
+    |    |
+    |    |      +--- Partition type byte.
+    |    |      |
+    |    |      |    +--- Ending CHS in INT 13 call format.
+    |    |      |    |
+    |    |      |    |        +-- Starting LBA.
+    |    |      |    |        |
+    |    |      |    |        |       +-- Size in sectors.
+    |    |      |    |        |       |
+    v <--+--->  v <--+-->     v       v
+
+   0  1  2  3  4  5  6  7  8 9 A B  C D E F
+   DH DL CH CL TB DL CH CL LBA..... SIZE....
+
+   80 01 01 00 06 0e be 94 3e000000 0c610900  1st entry
+
+   00 00 81 95 05 0e fe 7d 4a610900 724e0300  2nd entry
+
+   00 00 00 00 00 00 00 00 00000000 00000000  3rd entry
+
+   00 00 00 00 00 00 00 00 00000000 00000000  4th entry
+
+Bytes 0-3 are used by the small program in the Master Boot Record
+to read the first sector of an active partition into memory.  The
+DH, DL, CH and CL above show which x86 register is loaded when
+the MBR program calls INT 13H AH=02H to read the active
+partition's boot sector.  See "How It Works -- Master Boot
+Record".
+
+These entries define the following partitions:
+
+1) The first partition, a primary partition DOS FAT, starts at
+   CHS 0H,1H,1H (LBA 3EH) and ends at CHS 294H,EH,3EH with a size
+   of 9610CH sectors.
+
+2) The second partition, an extended partition, starts at CHS
+   295H,0H,1H (LBA 9614AH) and ends at CHS 37DH,EH,3EH with a
+   size of 34E72H sectors.
+
+3) The third and fourth table entries are unused.
+
+PARTITION TABLE RULES
+
+Keep in mind that there are NO written rules and NO industry
+standards on how FDISK should work but here are some basic rules
+that seem to be followed by most versions of FDISK:
+
+1) In the MBR there can be 0-4 "primary" partitions, OR, 0-3
+   primary partitions and 0-1 extended partition entry.
+
+2) In an extended partition there can be 0-1 "secondary"
+   partition entries and 0-1 extended partition entries.
+
+3) Only 1 primary partition in the MBR can be marked "active" at
+   any given time.
+
+4) In most versions of FDISK, the first sector of a partition
+   will be aligned such that it is at head 0, sector 1 of a
+   cylinder.  This means that there may be unused sectors on the
+   track(s) prior to the first sector of a partition and that
+   there may be unused sectors following a partition table
+   sector.
+
+   For example, most new versions of FDISK start the first
+   partition (primary or extended) at cylinder 0, head 1, sector
+   1. This leaves the sectors at cylinder 0, head 0, sectors
+   2...n as unused sectors.  This same layout may be seen on the
+   first track of an extended partition.  See example 2 below.
+
+   Also note that software drivers like Ontrack's Disk Manager
+   depend on these unused sectors because these drivers will
+   "hide" their code there (in cylinder 0, head 0, sectors
+   2...n).  This is also a good place for boot sector virus
+   programs to hang out.
+
+5) The partition table entries (slots) can be used in any order.
+   Some versions of FDISK fill the table from the bottom up and
+   some versions of FDISK fill the table from the top down.
+   Deleting a partition can leave an unused entry (slot) in the
+   middle of a table.
+
+6) And then there is the "hack" that some newer OS's (OS/2 and
+   Linux) use in order to place a partition spanning or passed
+   cylinder 1024 on a system that does not have a CHS translating
+   BIOS.  These systems create a partition table entry with the
+   partition's starting and ending CHS information set to all
+   FFH.  The starting and ending LBA information is used to
+   describe the location of the partition.  The LBA can be
+   converted back to a CHS -- most likely a CHS with more than
+   1024 cylinders.  Since such a CHS can't be used by the system
+   BIOS, these partitions can not be booted or accessed until the
+   OS's kernel and hard disk device drivers are loaded.  It is
+   not known if the systems using this "hack" follow the same
+   rules for the creation of these type of partitions.
+
+There are NO written rules as to how an OS scans the partition
+table entries so each OS can have a different method.  For DOS,
+this means that different versions could assign different drive
+letters to the same FAT file system partitions.
+
+PARTITION NESTING
+
+What do I mean when I say the partitions are "nested" within each
+other?  Lets look at this example:
+
+     M = Master Boot Record (and any unused sectors
+         on the same track)
+     E = Extended partition record (and any unused sectors
+         on the same track)
+   pri = a primary partition (first sector is a "boot" sector)
+   sec = a secondary partition (first sector is a "boot" sector)
+
+
+  |<----------------the entire disk-------------->|
+  |                                               |
+  |M<pri>                                         |
+  |                                               |
+  |      E<sec><---rest of 1st ext part---------->|
+  |                                               |
+  |            E<sec><---rest of 2nd ext part---->|
+
+
+The first extended partition is described in the MBR and it
+occupies the entire disk following the primary partition.  The
+second extended partition is described in the first extended
+partition record and it occupies the entire disk following the
+first secondary partition.
+
+PARTITION TABLE LINKING
+
+What do I mean when I say the partition records (tables) form a
+"linked" list?  This means that the MBR has an entry that
+describes (points to) the first extended partition, the first
+extended partition table has an entry that describes (points to)
+the second extended partition table, and so on.  There is, in
+theory, no limited to out long this linked list is.  When you ask
+FDISK to show the DOS "logical drives" it scans the linked list
+looking for all of the DOS FAT type partitions that may exist.
+Remember that in an extended partition table, only two entries of
+the four can be used (rule 2 above).
+
+And one more thing...  Within a partition, the layout of the file
+system data varies greatly.  However, the first sector of a
+partition is expected to be a "boot" sector.  A DOS FAT file
+system has:  a boot sector, first FAT sectors, second FAT
+sectors, root directory sectors and finally the file data area.
+See "How It Works -- OS2 Boot Sector".
+
+
+EXAMPLE 1
+
+A disk containing four DOS FAT partitions (C, D, E and F):
+
+
+  |<---------------------the entire disk------------------->|
+  |                                                         |
+  |M<---C:--->                                              |
+  |                                                         |
+  |           E<---D:---><-rest of 1st ext part------------>|
+  |                                                         |
+  |                      E<---E:---><-rest of 2nd ext part->|
+  |                                                         |
+  |                                 E<---------F:---------->|
+
+
+EXAMPLE 2
+
+So here is an example of a disk with two primary partitions, one
+DOS FAT and one OS/2 HPFS, plus an extended partition with
+another DOS FAT:
+
+
+  |<------------------the entire disk------------------>|
+  |                                                     |
+  |M<pri 1 - DOS FAT>                                   |
+  |                                                     |
+  |                  <pri 2 - OS/2 HPFS>                |
+  |                                                     |
+  |                                     E<sec - DOS FAT>|
+
+
+Or in more detail ('n' is the highest cylinder, head or sector
+number number allowed in the indicated field of the CHS)...
+
+
+            +-------------------------------------+
+ CHS=0,0,1  | Master Boot Record containing       |
+            | partition table search program and  |
+            | a partition table                   |
+            | +---------------------------------+ |
+            | | DOS FAT partition description   | | points to CHS=0,1,1
+            | +---------------------------------+ | points to CHS=a
+            | | OS/2 HPFS partition description | |
+            | +---------------------------------+ |
+            | | unused table entry              | |
+            | +---------------------------------+ |
+            | | extended partition entry        | | points to CHS=b
+            | +---------------------------------+ |
+            +-------------------------------------+
+CHS=0,0,2   | the rest of "track 0" -- this is    | :
+to          | where the software drivers such as  | : normally
+CHS=0,0,n   | Ontrack's Disk Manager or Micro     | : unused
+            | House's EZ Drive are located.       | :
+            +-------------------------------------+
+CHS=0,1,1   | Boot sector for the DOS FAT         | :
+            | partition                           | : a DOS FAT
+            +-------------------------------------+ : file
+CHS=0,1,2   | rest of the DOS FAT partition       | : system
+to          | (FAT table, root directory and      | :
+CHS=x-1,n,n | user data area)                     | :
+            +-------------------------------------+
+CHS=x,0,1   | Boot sector for the OS/2 HPFS       | :
+            | file system partition               | : an OS/2
+            +-------------------------------------+ : HPFS file
+CHS=x,0,2   | rest of the OS/2 HPFS file system   | : system
+to          | partition                           | :
+CHS=y-1,n,n |                                     | :
+            +-------------------------------------+
+CHS=y,0,1   | Partition record for the extended   |
+            | partition containing a partition    |
+            | record program (never executed) and |
+            | a partition table                   |
+            | +---------------------------------+ |
+            | | DOS FAT partition description   | | points to CHS=b+1
+            | +---------------------------------+ |
+            | | unused table entry              | |
+            | +---------------------------------+ |
+            | | unused table entry              | |
+            | +---------------------------------+ |
+            | | unused table entry              | |
+            | +---------------------------------+ |
+            +-------------------------------------+
+CHS=y,0,2   | the rest of the first track of the  | : normally
+to          | extended partition                  | : unused
+CHS=y,0,n   |                                     | :
+            +-------------------------------------+
+CHS=y,1,1   | Boot sector for the DOS FAT         | :
+            | partition                           | : a DOS FAT
+            +-------------------------------------+ : file
+CHS=y,1,2   | rest of the DOS FAT partition       | : system
+to          | (FAT table, root directory and      | :
+CHS=n,n,n   | user data area)                     | :
+            +-------------------------------------+
+
+EXAMPLE 3
+
+Here is a partition record from an extended partition (the first
+sector of an extended partition).  Note that it contains no
+program code.  It contains only the partition table and the
+signature data.
+
+OFFSET 0 1 2 3  4 5 6 7  8 9 A B  C D E F  *0123456789ABCDEF*
+000000 00000000 00000000 00000000 00000000 *................*
+000010 TO 0001af SAME AS ABOVE
+0001b0 00000000 00000000 00000000 00000001 *................*
+0001c0 8195060e fe7d3e00 0000344e 03000000 *.....}>...4N....*
+0001d0 00000000 00000000 00000000 00000000 *................*
+0001e0 00000000 00000000 00000000 00000000 *................*
+0001f0 00000000 00000000 00000000 000055aa *..............U.*
+
+NOTES
+
+Thanks to yue@heron.Stanford.EDU (Kenneth C. Yue) for pointing
+out that in V0 of this document I did not properly describe the
+unused sectors normally found around the partition table sectors.
+
+/end/
+-- 
+\\===============\\=======================\\
+ \\  Hale Landis  \\      303-548-0567     \\
+ // Niwot, CO USA // landis@sugs.tware.com //
+//===============//=======================//