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ATA/ATAPI-5

Not content to rest on their laurels with the adoption of ATA/ATAPI-4, the T13 committee immediately began work on its next generation, ATA/ATAPI-5. This standard was published by ANSI in 2000 as NCITS 340-2000, AT Attachment with Packet Interface - 5.

The changes defined in ATA/ATAPI-5 include:

• New Ultra DMA Modes: Higher-speed Ultra DMA modes 3 and 4, defining transfer rates of 44.4 and 66.7 MB/s were specified.
• Mandatory 80-Conductor IDE Cable Use: The improved 80-conductor IDE cable first defined in ATA/ATAPI-4 for optional use, is made mandatory for UDMA modes 3 and 4. ATA/ATAPI-5 also defines a method by which a host system can detect if an 80-conductor cable is in use, so it can determine whether or not to enable the higher speed transfer modes.
• Miscellaneous Command Changes: A few interface commands were changed, and some old ones deleted.

Like ATA-3, not that many changes were made in ATA/ATAPI-5 (compared to ATA/ATAPI-4 and ATA-2, for example). Unlike ATA-3, the main change made here was a high-profile one: another doubling of the throughput of the interface to 66.7 MB/second. Unsurprisingly, the same companies that called ATA/ATAPI-4 drives "Ultra ATA/33" labeled ATA/ATAPI-5 drives running Ultra DMA mode 4 as "Ultra ATA/66". During 1999 and early 2000, new IDE/ATA drives conforming to this standard were the most common on the market.

Next: ATA/ATAPI-6

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