Hardware Reference
In-Depth Information
• Advanced power management support
• An optional 80-conductor, 40-pin cable defined for improved noise resistance
• Host protected area (HPA) support
• Compact Flash Adapter (CFA) support
•EnhancedBIOSsupportfordrivesover9.4ZB(zettabytes ortrilliongigabytes)insize
(even though ATA was still limited to 136.9GB)
The speed and level of ATA support in your system is mainly dictated by your mother-
board chipset. Most motherboard chipsets come with a component called either a South
Bridge or an I/O Controller Hub that provides the ATA interface (as well as other func-
tions) in the system. Check the specifications for your motherboard or chipset to see
whether yours supports the faster ATA/33, ATA/66, ATA/100, or ATA/133 mode. One in-
dication is to enter the BIOS Setup, put the hard disk on manual parameter settings (user
defined), and see which (if any) Ultra-DMA modes are listed. Most boards built in 1998
support ATA/33. In 2000 they began to support ATA/66, and by late 2000 most started
supporting ATA/100. ATA/133 support became widespread in mid-2002.
ATA-4 made ATAPI support a full part of the ATA standard; therefore, ATAPI was no
longer an auxiliary interface to ATA but merged completely within it. Thus, ATA-4 pro-
moted ATA for use as an interface for many other types of devices. ATA-4 also added
support for new Ultra-DMA modes (also called
Ultra-ATA
) for even faster data transfer.
Thehighest-performance mode,called
UDMA/33
,had33MBpsbandwidth—twice thatof
the fastest programmed I/O mode or DMA mode previously supported. In addition to the
higher transfer rate, because UDMA modes relieve the load on the processor, further per-
formance gains were realized.
Anoptional 80-conductor cable (with cable select) isdefined forUDMA/33transfers. Al-
though this cable was originally defined as optional, it would later be required for the
faster ATA/66, ATA/100, and ATA/133 modes in ATA-5 and later.
Supportforareservedareaonthedrivecalledthe
HPA
wasaddedviaanoptional
SET MAX
ADDRESS
command. This enables an area of the drive to be reserved for recovery software.
Also included was support for queuing commands, similar to those provided in SCSI-2.
This enabled better multitasking as multiple programs request ATA transfers.
Another standard approved by the T13 committee in 1998 was “ANSI NCITS 316-1998
1394 to AT Attachment - Tailgate,” which is a bridge protocol between the IEEE 1394
(i.LINK/FireWire)busandATAthatenablesATAdrivestobeadaptedtoFireWire.A
tail-
gate
isanadapterdevice(basicallyasmallcircuitboard)thatconvertsIEEE1394(i.LINK
