Ultra ATA/100

[CPU Trubble]

I bought a new WD hard drive with Ultra ATA/100 support. Someone please explain this feature.

[Budfred]

Drives generally function at ATA 33, 66, 100, and I think some now at 100. This reflects the speed at which the drive can communicate with the motherboard and CPU. ATA100 is good if your motherboard supports it. It is downward compatible, so it should work even if you have ATA66 on the IDE channels of the motherboard.

Budfred

[Whyzman]

ATA also known as IDE is the most common interface for computers. The numbers 33, 66, 100, 133 denote the "burst" rate of data transfers.

A true indicator of performance is "sustained" rate, although most drive manufacturers advertise their faster burst rate.

Sustained transfers refer to a continued transfer that does not occur from the drive cache. Burst rates refer to data transferred directly to/from the high speed cache. Solid-state cache memory is thousands of times faster than the spinning platter of a hard drive.

Therefore, a large cache will significantly impact performance.

A typical ATA/100 hard drive bursts at about 100MB/sec from the cache, but has a sustained rate of about 26-42MB/sec, depending on the drive. If you consider a best-case scenario with the 2MB cache full of data, 100MB/sec will quickly deplete the cache and commence transferring at the lower sustained rate.