Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!portal!cup.portal.com!ts
From: ts@cup.portal.com (Tim W Smith)
Newsgroups: comp.unix.xenix,comp.unix.i386
Subject: Re: ESDI vs SCSI
Message-ID: <17478@cup.portal.com>
Date: 22 Apr 89 11:04:12 GMT
References: <6628@mrspoc.UUCP>
Distribution: na
Organization: The Portal System (TM)
Lines: 19

Another thing to think about is SCSI-2.  SCSI-2 will have several
attractive features, such as a much higher data transfer rate,
and more intelligence on the drives.

For instance, SCSI-2 allows for command queueing in devices.  When
you send a device a queued command, the drive is allowed to place
the command in a queue.  There can be up to 256 commands queued.
The drive can then execute these commands in an optimal ordering.

SCSI-1 drives will work under SCSI-2, and SCSI-1 controllers will
be able to work with SCSI-2 peripherals with only software changes,
so if you chose SCSI-1 now, your peripheral will still work if you
decide to upgrade to SCSI-2 later.  With ESDI you may get stuck.

The extra command overhead of SCSI vs. ESDI is going away.  There
are SCSI controller chips that will soon be available that should
cut this down to the 200 to 300 microsecond range.

					Tim Smith