			UltraDMA Driver for DOS

This is a DOS driver, intended to run ONLY a single UltraDMA hard disk
on south bridges made by Intel, VIA, SiS, ALi, and other manufacturers.
It CANNOT be used with add-on IDE controller cards having on-board BIOS
that already supports UltraDMA like Promise, SiiG, Adaptec etc.

For optimum and error-free performance, we recommended that you install
your hard disk as a single master drive on the IDE channel, preferably
primary. Coexistence of a slave drive is allowed, but was never tested!
In this case, as the ATA/ATAPI-7 standard says, "Mode shall be selected
no higher than the highest mode supported by the slowest device". So we
don't recommend you connect a slower slave together with a fast master.

For modes higher than 2 (ATA-33), you MUST use 80-conductor IDE cable.
Also consider the following excerpt from the ATA/ATAPI-7 specification:

***********************************************************************
The host shall be placed at one end of the cable. It's recommended that
for a single device configuration the device be placed at the opposite
end of the cable from the host. If a single device configuration is
implemented with the device not at the end of the cable, a cable stub
results that may cause degradation of signals. Single device
configurations with the device not at the end of the cable shall not be
used with Ultra DMA modes.
***********************************************************************

UDMA mode is set to the highest common mode supported by your disk and
chipset. Its value must had been initialised by your BIOS (this doesn't
mean that the BIOS will actually USE it!). The driver handles only read
and write requests to the FIRST PHYSICAL disk. All other requests (seek
etc.) are "passed" back to the BIOS or some other driver for handling.

The disk is assumed to support standard LBA mode (63 sectors, 255 heads
and its "designed" number of cylinders). The driver supports 28-bit LBA
mode (BIOS commands 42h read, 43h write) and handles up to 128 GB disks
in MS-DOS 7.0+, PC-DOS 7.1, FreeDOS etc. The old 24-bit CHS mode (BIOS
commands 2 read, 3 write) is still supported for MS-DOS v6.x and below.
CHS mode requires all user files to be on the first 8 GB of the disk.
More data, if present, must be in other disk partitions, and accessed
via other operating systems which support LBA mode.

Version 2.0+ of this driver is changed, so that if the user I/O buffer
is not DWORD-aligned, fails a VDS "lock" or crosses a 64 KB boundary, a
request shall be processed through a 4 KB driver buffer, using UltraDMA
I/O to and from the buffer. This prevents "passing" any I/O request
back to the BIOS for execution in slow PIO mode, as in older versions
of the driver. Not crossing a 64K DMA boundary is required by the Bus
Master IDE specification, and DWORD alignment - by the Intel chipsets.

Load the driver in CONFIG.SYS after any XMS/UMB drivers but BEFORE any
disk caching programs like this: DEVICE[HIGH]=[path]UDMA.SYS

Spread and enjoy!
Jack and Luchezar
