OS2IDE2X Driver Documentation
	       ----------------------------------


	Enclosed is the OS2IDE2X.ADD. It contains a number
	of changes from the previous driver. This note is
	intended to help explain those changes.


    Section 1:

	Summary of Changes
	------------------

	Multiple Controller support

	- 2 independent controllers can be supported per instance
	  of this driver.

	- Multiple instances of the driver may be loaded


	Improved Geometry Support and  >1024 Cyl support

	- The driver will attempt to determine drive geometry
	  by the following methods:

	  -- Via command line switches
	  -- Via an IDENTIFY command issued to the drive
	  -- Via the Fixed Drive Tables

	  This driver will support disks >1024 cylinders
	  if indicated by one of the above geometry sources.

	- The driver can display the BIOS (Int 13), IDENTIFY,
	  Command Line geometries and the geometry selected
	  by the driver.


	Error Handling/Recovery

	- The driver no longer issues "Power Management"
	  commands.

	  Regardless of what CAM states there appears to
	  be no industry wide consensus on what these commands
	  should be. In addition sufficient attention has
	  not been paid to compatibility issues with older
	  MFM/RLL and IDE controllers.


	- Error recovery is driven by elapsed time

	  Error recovery in this driver has been restructured.
	  When an error occurs, retries will be done periodically
	  over a set time interval. This should allow drives which
	  have "spun-down" to recover.

	- Soft-Reset used to help clear error conditions

	  The driver will issue a soft reset via 3F6 to recover
	  from timeouts and from persistent error conditions.


	Command Line Switches
	---------------------

	 Sample Command Lines:

	 BASEDEV=OS2IDE2X.ADD /V /A:0 /U:0 /T:10 /GEO:(1314,7,26,-1) /A:1 /I

	 BASEDEV=OS2IDE2X.ADD /V /A:1 /P:120 /IRQ:11 /U:0 /T:10

	 BASEDEV=OS2IDE2X.ADD /V /A:1 /U:0 /GEO:20

	 BASEDEV=OS2IDE2X.ADD /V /A:0 /U:0 /SMS

	 BASEDEV=OS2IDE2X.ADD /V /A:0 /!R


	 Switch definitions:

	   /V = Verbose Mode

	   Displays controller status and drive geometry information
	   during OS/2 initialization.


	   /A:0 = Adapter number

	   Adapter 0 has default parameters for a primary adapter.
	   Adapter 1 has default parameters for a secondary adapter.


	   /U:0 = Unit Id

	   Unit 0 indicates parameters apply to the master unit.
	   Unit 1 indicates parameters apply to the slave unit.


	   /T:10 = Error retry time in seconds. (dec)

	   Indicates the total allowable error recover time for
	   a request. Error recovery times < 5 seconds will be
	   ignored. This parameter defaults to 30 seconds. A shorter
	   interval may be desirable for fault tolerant applications.


	   /GEO:(1314,7,26,-1) or /GEO:20 = Drive geometry override (dec)

	   Indicates the Cylinder/Head/Sector geometry for the drive.
	   The fourth parameter is the Write Precompensation Cylinder
	   which may be omitted for drives which do not require
	   precompensation.

	   As an alternate format standard BIOS drive types may
	   be used. Types (0-47) are supported. User defined types
	   48, 49 should be entered directly by in the previous
	   format.

	   When specified, this parameter overrides other geometry sources.
	   If this parameter is absent, other geometry sources discussed
	   above will be used.


	   /I = Ignore adapter

	   The driver automatically attempts to locate and initialize
	   both the primary and secondary adapters. In some cases other
	   DASD controllers may appear between the primary and secondary
	   IDE controllers. In these cases the system should be configured
	   as follows:

	   BASEDEV=OS2IDE2X.ADD /V /A:1 /I
	   BASEDEV=MOREDASD.ADD
	   BASEDEV=OS2IDE2X.ADD /V /A:0 /I


	   /!R = Disable adapter resets

	   Disables adapter resets. In most cases resets are beneficial
	   to assist in recovering from transient hardware problems
	   such as lost interrupts, timeouts, or commands a particular
	   adapter may not support.

	   However, for some ESDI adapters, options set by vendor
	   unique commands such as 'Sector Sparing' may be lost after
	   after a reset. Setting this switch is recommended for ESDI
	   adapters with disks formatted using 'Sector Sparing'.


	   /P:120 or /PORT:120 = Base Port address (hex)

	   Overrides the default Base Port address for this adapter.
	   Ports are still assigned in this case would be (120-127) and
	   (326). The default port addresses for Adapter 0 is (1F0) and
	   for Adapter 1 is (170).


	   /IRQ:11 = IRQ Number (dec)

	   Overrides the default IRQ Number for this adapter. The default
	   IRQ address for Adapter 0 is (14) and for Adapter 1 is (15).

	   /SMS = Enable Set Multiple Mode support

	   This switch enables Set Multiple Support which the improves
	   performance of some IDE drives. If the drive does not have
	   this feature, this switch will be ignored. The /V - (Verbose)
	   option will indicate whether this feature has been enabled
	   on a particular drive.



    Section 2:

	Install Method :

	   There are two methods to install this driver to OS/2

	   Method 1. Put this driver disk in Drive A:
		     In OS2 Command Prompt type

		     C:>ddinstall

		     and press ENTER key

		     OS2 will automatic install this driver to system !

	   Method 2. Copy OS2IDE2X.ADD from driver diskette to \OS2
		     Edit \CONFIG.SYS

		     Add a REM to the line contain BASEDEV=IBM1S506.ADD

		       BASEDEV=IBM1S506.ADD ---> REM BASEDEV=IBM1S506.ADD

		     ADD another line to CONFIG.SYS

		       BASEDEV=OS2IDE2X.ADD

		     You can add options as described in Section 1 Command
		     Line Switch !