
	+===========================================+
	|    VG4 Hard Disk Driver for IBM OS/2 WARP |
	+===========================================+

     VG4.ADD is the hard disk driver for IBM OS/2 WARP.

     Your VG4 disk controller needs this device driver to take the
     advantage of the high performance 32-bit VL-Bus when running under
     OS/2.

     ********* Installing the Driver *********

     1. Delete the original IBM OS/2 hard disk driver.

	Delete the command line "BASEDEV = IBM1S506.ADD" from the CONFIG.SYS
	file, if it exists.

     2. Install the OS/2 driver.

	Copy VG4.ADD to the subdirectory, /OS2, of your system.

	Use a text editor to edit the CONFIG.SYS file. Add the following
	line:

	BASEDEV = VG4.ADD /...(Please refer to next paragraph for the switch defintion)


     3. Reboot the system.

     ********* Switch Definition *********

     /V = Verbose Mode

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


     /A:n = Adapter number

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


     /U:n = 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=VG4.ADD /V /A:1 /I
	   BASEDEV=MOREDASD.ADD
	   BASEDEV=VG4.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'.


     /!SMS = Disable Set Multiple Mode support

	   This switch disables Set Multiple Support which the improves
	   performance of some IDE drives. The /V - (Verbose) option
	   will indicate whether this feature has been enabled
	   on a particular drive.
	   The Set Multiple Support is default enabled if the drive have
	   this feature.

     /LBA = OS/2 access the drive using LBA addressing.

	   This switch enables the OS/2 write commands with LBA-addressing
	   to the drive. 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.


     /PIOSPEED:n = Set the drive PIO speed n

	   The PIO speed of drive is from 0 to 8 or A.

     /DMASPEED:n = Set the drive DMA speed

	   The DMA speed of drive is from 0 to 8. If the drive does not have
	   this feature, the switch will be ignored and the driver will
	   automatically detect and set the speed of drive.

	   NOTICE: Only one speed mode can be specified.
	   If user set improper speed of a drive, the drive maybe not work.
	   The driver will automatically detect and set the speed of drive
	   if user does not specify it.

     ********* Examples *********

	 BASEDEV=VG4.ADD /V /A:0 /U:0 /T:10 /GEO:(1314,7,26,-1) /A:1 /I

	 BASEDEV=VG4.ADD /V /A:1 /U:0 /GEO:20

	 BASEDEV=VG4.ADD /V /A:0 /U:0 /!SMS

	 BASEDEV=VG4.ADD /V /A:0 /U:0 /LBA

	 BASEDEV=VG4.ADD /V /A:0 /!R

	 BASEDEV=VG4.ADD /V /A:0 /U:0 /DMASPEED:7

	 BASEDEV=VG4.ADD /V /A:0 /U:0 /PIOSPEED:5 /U:1 /PIOSPEED:6

     ********* Enhanced IDE Hard Drive *********

	If you have an Enhanced IDE hard drive that has a capacity of
	greater than 528M (greater than 1024 cylinders), note
	the follow restriction :

	 o The FAT file system is limited to partition sizes of less
	   than 1024 cylinders.

	 o The HPFS file system can support data partition that are
	   greater than 1024 cylinders. Howerver the partition from
	   which OS/2 is started cannot be greater than 1024 cylinders.
	   The HPFS file system can support drives up to 2GB.

	For breaking the restriction, you can enable the drive LBA mode
	in BIOS (VG4 BIOS or Main BIOS with this support).
	BIOS will perform LBA translation for this drive, then the CHS
	geometry of this drive at Int 13h interface is different
	from the real one. The translated number of cylinders will
	less than 1024.

	From making partitions of the drive to using the drive,
	please keep the SAME SELECTION on the drive LBA mode in BIOS.
	If you alter your selection, the data corruption may happens.
