🚀 go-pugleaf

That's it. Clear and precise.
Keith R. Williams wrote in message ...
>On Thu, 4 Dec 1997 04:28:10, hahn@neurocog.lrdc.pitt.edu (Mark
>Hahn) wrote:
>
>> : I'm not sure I understand you comment here, but if you're
>> : suggesting that IDE drives can do multiple requests, I disagree
>> : 100%.  SCSI drives can re-order requests to meet the physical
>> : limitations of the drive.  I've seen no evidence that IDE drives
>> : can do this.  I woulldn't expect it either.
>>
>> there's limited opportunity for tagged command queueing to provide any
>> benefit, since reasonable OSs already sort device request queues.  do you
>> have some evidence that TCQ is a major win?  remember that ATA drives
>> already do readahead and write-behind in nontrivial-sized caches.
>
>If the drive (channel actually) has already been issued a request
>all is halted until that request is served.  SCSI drives can
>order the responses to better match the requests. IDE simply
>cannot reorder requests.  If you want evidence, put your CDROM on
>your primary IDE channel and look at your performance tank when
>it's in use.
>
>Again, I'm not saying that SCSI is better than IDE.  In some
>circumstances it is.  On the desktop/client side (we're talking
>x86 here), I know of only one application that needs SCSI (DV).
>Certainly as x86 systems take over the UNIX world this will
>change.  On the server side, please, there is no competition.
>But, just because SCSI is better on a server does *not* mean it's
>better on a client/stand-alone.  I don't want SCSI at home!
>
>----
>  Keith R. Williams
>  krw@ibm.net
>