		  UDMA - the Ultra DMA Driver for DOS
		  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is a DOS driver, intended to run Ultra DMA hard disk(s) on "south
bridges" made by Intel, VIA, SiS, ALi, and other manufacturers. It can
NOT be used with add-on IDE controller cards having on-board BIOS that
already supports Ultra DMA like Promise, SiiG, Adaptec, etc.

There are actually two drivers in this package - UDMA (for a single HDD
up to 128 GiB) and UUDMA (Universal UDMA - for up to 4 HDD any of which
can be above 128 GiB). If you have only one hard disk not above 128 GiB
you should use UDMA, as it uses less resident memory and tells you more
on loading. But if you have more Ultra DMA hard disks or any disk above
128 GiB that are connected to your "south bridge" you should use UUDMA.

For optimum and error-free performance, we recommended that you install
your hard disk as a single master drive on the primary IDE channel. In
case of two IDE devices on same channel, the ATA/ATAPI-7 standard says
that "Mode shall be selected no higher than the highest mode supported
by the slowest device". So we don't recommend you connect a slow slave
together with a fast master.

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

! 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. 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 LBA mode
for MS-DOS 7.0+, PC-DOS 7.1, ROM-DOS, FreeDOS, new DR-DOS 7.0 versions
and PTS-DOS 32 (the only one untested). CHS mode is also supported for
MS-DOS 6.x and below, but it requires that all user files are on the
first 8 GB of the disk; more data, if present, must be in other disk
partitions and accessed via other operating system supporting LBA mode.

In case 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 64 KB
XMS buffer, using Ultra DMA I/O to and from the buffer. (Not crossing a
64 KB DMA boundary is required by the Bus Master IDE specification, and
DWORD alignment - by the Intel "south bridges".) Only requests for over
64 KB of data (which DOS can't issue) are passed back to the BIOS.

Load the driver through your "CONFIG.SYS" after the memory managers but
BEFORE the disk caching program, like this: DEVICE[HIGH]=[path]UDMA.SYS

							Spread & enjoy!
							Jack & Luchezar
