Date: Tue, 12 Dec 1995 19:18:29 -0500 (EST) From: John Capo <jc@irbs.com> To: ctassell@isn.net Cc: freebsd-isp@FreeBSD.ORG Subject: Re: SCSI vs EIDE Message-ID: <199512130018.TAA20346@irbs.irbs.com> In-Reply-To: <199512121028.GAA15284@phoenix.isn.net> from "Charles Tassell" at Dec 12, 95 05:10:59 am
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Charles Tassell writes:
>
> I'm setting up an ISP for a guy who REALLY wants to use EIDE 4 drives
> (transfer rate around 12 meg/s I think he said) Now considering the fact that
> all PCI boards come with build in EIDE controllers in them, why is everyone so
> big on SCSI?
>
> I'd personally rather use SCSI myself, just because I have doubts as to
> whether or not EIDE is really as stable as they say, but I may be outvoted in
> this. Can anyone out there come up with some convincing arguments why to go
> SCSI? BTW: The machine is going to be an all-in one server: news, mail, WWW,
> DNS, terminal server (yey! this wont crash often <S>) And, we might run BSD
> instead of FreeBSD.
>
I am not at all familiar with EIDE. Perhaps it has some of these
SCSI features.
1) Overlapped I/O. I/O requests outstanding on all targets at the
the same time.
2) BUS mastering DMA. Minimal computes needed to move the bits.
3) 7 disks/tapes per bus.
4) Trivial to add large capacity DAT drives.
5) Automatic bad sector remapping.
6) Tagged queueing. Multiple I/O requests outstanding to each target.
7) Wide SCSI is really fast.
8) Better support for SCSI in most if not all *nixes.
If they insist on one machine, make sure it has /plenty/ of memory.
John Capo jc@irbs.com
IRBS Engineering High performance FreeBSD systems
(305) 792-9551 Unix/Internet Consulting - ISP Solutions
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