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[ The PC Guide | Systems and Components Reference Guide | Hard Disk Drives | Hard Disk Interfaces and Configuration | Integrated Drive Electronics / AT Attachment (IDE/ATA) Interface | Unofficial IDE/ATA Standards and Marketing Programs ]

Ultra ATA/100

If you've already read my discussions of Ultra ATA/33 and Ultra ATA/66, you can probably guess what I am going to say on this page already. :^) Yes, Ultra ATA/100 is the marketing term for hard disks that use the new Ultra DMA mode 5, supporting interface transfers at 100 MB/s. This new Ultra DMA mode is the fastest available as of this writing in late 2000. It has not been codified in any formally approved and published ATA standard, but will be documented in the new ATA/ATAPI-6 standard that is currently under development.

Pretty much all new ATA drives are now sold using some variant of the "Ultra ATA/100" moniker. Note that for a few weeks in 2000, some IBM "Ultra ATA/100" Deskstar drives were advertised as the somewhat strange "Ultra ATA/66+". The story behind this is rather amusing. Earlier in that year, work was progressing on drafts for the new ATA/ATAPI-6 standard. The key feature of this new standard was Ultra DMA mode 5, allowing interface speeds of 100 MB/s. Even though all hard drive companies are now selling drives that operate at this speed (despite the fact that ATA/ATAPI-6 is still in development), there apparently was some sort of agreement in place that no drives would be marketed at the 100 MB/s speed before a particular date. Someone at IBM obviously jumped the gun, and specifications for IBM Ultra ATA/100 drives began showing up early on the Internet. Unsurprisingly, people started asking what exactly this was all about!

So IBM apparently had to stop selling the drives as "Ultra ATA/100". They still wanted to send everyone the message, however, that these drives would be compatible with the new higher-speed transfer mode. So some marketing genius decided to label the drives as "Ultra ATA/66+". :^) I often praise IBM in my hard disk materials for their industry leadership role, but this was a really silly move in my opinion. Since of course nobody knew what on earth "Ultra ATA/66+" was supposed to mean, this led to even more confusion than the too-early use of "Ultra ATA/100" did. Fortunately, a couple of months later the magic date (whatever it was) passed and the "Ultra ATA/66+" nonsense went away, replaced with "Ultra ATA/100" again. You can still find mention of "66+" around, if you do some searching for that term on the web.

Next: Plug and Play ATA


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