Re: Difference between IDE and SCSI ??

Les Mikesell wrote:

Ben Kamen wrote:

In the beginning, SCSI was always faster than IDE because the intelligence of the drives (remember, IDE tends to be dumb as it's controlled by the host), that lent the drives to be more expensive. So think "server" and thus smarter, more expensive also demanded "faster".

Scsi needs less intervention by the main CPU but that doesn't necessarily translate to 'faster'. The overall time is going to be limited by the seek and transfer rate of the drive itself, which is often identical between IDE and Scsi models. The tradeoff in cost of putting intelligence on peripheral devices and the value of those extra main CPU cycles (often spent waiting idly in is single-user computer anyway) has bounced back and forth over the years. In a file server with lots of drives, scsi is usually a big win compared to typical ide controllers because it lets all the disks seek independently at the same time. However even that isn't quite so simple, since specialized controllers like the 3ware raid cards can do the same with ide drives and also offload the work from the main CPU.

True true... the drive is ultimately a bottleneck... I should have mentioned.

but let's talk 20 years ago. I realize a lot of the technology has caught up
to today. A lot of the performance arguments these days are kinda moot.

 -Ben

--
Ben Kamen - O.D.T., S.P.
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