Re: Please Advise: SCSI vs. IDE

Bryn Paul Arnold Jones (
Sat, 28 Sep 1996 15:02:19 +0100 (BST)

On Fri, 27 Sep 1996, Steven N. Hirsch wrote:
> > wrote:
> > : 486 SX 33 Mhz
> > : 16 Meg RAM
> > : SVGA Trident video card and Samsung Monitor
> > : 170 Meg HD primary
> > : 250 Meg HD secondary
> > : soundcard
> > : Adaptec 1542CP (PNP disabled with switches on card)
> > : Toshiba 3401 2X CD Drive external
> > :
> > : I want to add a 2 Gig HD to this config. Should I put it on the
> > : SCSI card or should I replace one of the IDE HD's??? What would be
> > : faster??? I want to put usenet newsgroups on it and allow user's to
> > : read/search...

Ok, I'll try to sort it out (for me at least ;). The main thing to
consider is what you want to use your box for, SCSI is much faster than
IDE with the box under load. If you almost never load your box, and have
fast IDE disks, then you'll not see much of a differance.

IDE was really designed as a quick hack (AFAIK) (or not designed, just
done), that let you put disks on an ISA bus with little or no electronics
on the adapter card (hence $20 for IDE/Serial/Parallel/Floppy multi IO
boards), all that went into the disk (hence master/slave), and a short
fixed lenth cable (hence no termination).

SCSI was there first, and was expensive, and complicated, but fast and
flexable. SCSI is still with us because of it's smart controller, that
can run (I think) 4 drives flat out at the same time with little or no
CPU time, unlike IDE which needs 100% CPU time for the duration of the
transfer (even triton IDE needs 100% CPU to setup the transfer, just it
dosn't to actually do the transfer).

SCSI is still expensive, where as the smart IDE drives are cheap (see
what mass production does). If you want to run a news spool, you need
SCSI (well if your just spooling 10 or so groups, for you and a few other
people, IDE would be adequate), if your running a server (serving
http/ftp/...), you need SCSI, if your running your personal box that
rarly has anyone else on, then you don't need SCSI ...

Don't get me wrong, IDE is just fine (I have only IDE drives in my box),
it's just that IDE can't cut it under a loaded enviroment, and it makes
things worse (you can't service interupts if your doing an IDE transfer,
you can if your waiting on a SCSI transfer).


PGP key pass phrase forgotten,   \ Overload -- core meltdown sequence 
again :( and I don't care ;)      |            initiated.
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