Hardware Reference
In-Depth Information
ATA-3 (ATA Interface-3)
ATA-3 was a comparatively minor revision to the ATA-2 standard that preceded it. It con-
sisted of a general cleanup of the specification and had mostly minor clarifications and
revisions. The most major changes included the following:
• Eliminated single-word (8-bit) DMA transfer protocols
• Added S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) support
for prediction of device performance degradation
• Made LBA mode support mandatory (previously it had been optional)
• Added ATA Security mode, allowing password protection for device access
• Provided recommendations for source and receiver bus termination to solve noise is-
sues at higher transfer speeds
ATA-3 built on ATA-2, adding improved reliability, especially of the faster PIO mode 4
transfers;however,ATA-3didnotdefinefastermodes.ATA-3didaddasimplepassword-
based security scheme, more sophisticated power management, and S.M.A.R.T. This en-
ables a drive to keep track of problems that might result in a failure and thus avoid data
loss. S.M.A.R.T. is a reliability prediction technology that IBM initially developed.
Work on ATA-3 began in 1995, and the standard was finished and officially published
in 1997 as “ANSI X3.298-1997, AT Attachment 3 Interface.” ATA-3 was officially with-
drawn in 2002.
ATA/ATAPI-4 (ATA with Packet Interface Extension-4)
ATA-4 included several important additions to the standard. It included the Packet Com-
mand feature known as the
AT Attachment Packet Interface
(ATAPI), which allowed
devices such as CD-ROM and CD-RW drives, LS-120 SuperDisk floppy drives, Zip
drives, tape drives, and other types of storage devices to be attached through a common
interface. Until ATA-4 came out, ATAPI was a separately published standard. ATA-4 also
added the 33MB per second (MBps) transfer mode known as Ultra-DMA or Ultra-ATA.
ATA-4 is backward compatible with ATA-3 and earlier definitions of the ATAPI.
Work on ATA-4 began in 1996, and the standard was finished and officially published in
1998 as “ANSI NCITS 317-1998, AT Attachment - 4 with Packet Interface Extension.”
The major revisions added in ATA-4 were as follows:
• Ultra-DMA (UDMA)or Ultra-ATA/33) transfer modes up to Mode 2, which is
33MBps (called UDMA/33 or Ultra-ATA/33)
• Integral ATAPI support
