Difference between IDE and SCSI ??
bkamen at benjammin.net
Sat Feb 2 23:23:44 UTC 2008
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.
Heck, I have 3 125GB IDE drives mounted onto my RS/6000's SCSI bus with SCSI-IDE
adapters as it was cheaper to get the adapters with drives than just large SCSI
Ben Kamen - O.D.T., S.P.
Email: bkamen AT benjammin DOT net Web: http://www.benjammin.net
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