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SubjectSCSI vs IDE swapping
Alan Cox wrote:
> > the afformentioned kernels, a cycle/IO hungry process can really impact
> > system performance. I was quite horrified comparing my Sparc clone
> > (SunOS 403) which had 8MB (12ms SCSI2 in SCSI1 mode HD) versus a 8MB
> > 486/33 (10ms ISA IDE HD) ... Granted the 486 would be slower, but the
> Your IDE disk drive is the big problem, it needs a lot of CPU supervision so
> swapping gets very very CPU intensive instead of being just a queueing
> operation with the card doing the smarts. 2.0.0 should be about as good as
> we can get on IDE (its a lot better all around for swapping than 1.2 as it
> uses very good algorithms now).
> Alan

Could you go a little deeper into this. On my desktop I have both
IDE and SCSI. My scsi drive is an old 28 millisec off a 2842a controller
but I've been using as the swap device for years(originally on a 1540a)
I've been tempted to replace it with a Fast Scsi II device but when I compare
the transfer speeds to the IDE why bother. 10 vs 14 meg. On the other hand
My laptop with ide only seems totally consumed with swapping. Due to the
difference in memory sizes DT=16M LT=8M i assumed memory or cache was the
problem DT=DX2-66 vs LT=DX4-100 since the laptop had the processor speed
advantage. I also have a 1522 compatible pcmcia card on the laptop for
CD and scanner purposes so I could add an external SCSI device. The laptop
IDE is a 1.2Gig Toshiba I don't know the specs. What are some of the
pro's and cons. Is the advantage SCSI controllers in general or are their
classes of them that make a difference cpu processing demands.


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