Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!apple!motcsd!xdos!doug
From: doug@xdos.UUCP (Doug Merritt)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Hard Drive/Controller
Message-ID: <551@xdos.UUCP>
Date: 30 Nov 89 16:28:09 GMT
References: <1989Nov21.224423.3829@athena.mit.edu> <18611@watdragon.waterloo.edu> <24531@cup.portal.com> <24278@swrinde.nde.swri.edu>
Reply-To: doug@xdos.UUCP (Doug Merritt)
Distribution: na
Organization: Hunter Systems, Mountain View CA (Silicon Valley)
Lines: 40

In article <24278@swrinde.nde.swri.edu> kent@swrinde.UUCP (Kent D. Polk) writes:
>How about ... a SCSI Tape Backup!
>How about a Mac SCSI scanner?

How about a SCSI remote file system for linking different systems?
Seems much more cost efficient than Ethernet.

>Is there a hardware limitation with the 2090A or other available SCSI
>controllers for Amigas which will not let them communicate with such
>devices or just a lack of software support?

Someone else will likely comment about hardware; I've heard some controllers
support only a subset of SCSI, but myself, I dunno the issues.

But there certainly are problems with software support. E.g. you need
a different kind of driver for SCSI tape, because a tape drive behaves
differently than a hard drive. Same for WORMs, scanners, etc.

An interesting approach to a *general* solution to this kind of problem
has been designed and implemented on Suns by Rich Morin of Canta Forda
Laboratory, Pacifica CA (named for his home computer, a fully loaded
Sun). It is described in an article in the December 1989 issue of Sun
Expert (second of two parts; first part in November is a
whet-your-appetite teaser on the subject).

I talked to Rich about it a few months ago. The idea is to create a really
*generic* SCSI driver. On unix this is of course /dev/scsi. Using this
via ioctl() system calls, potentially you can talk to any kind of SCSI
device at all from an application program.

I don't know the details yet (haven't seen the Dec. Sun Expert), but I
believe this means that you still need to write new C code for new types
of SCSI devices, but that much of the complications are shifted out of
the custom code and into the generic SCSI driver.

Sounds like a good idea, and one that should be adapted for the Amiga.
	Doug
-- 
Doug Merritt		{pyramid,apple}!xdos!doug
Member, Crusaders for a Better Tomorrow		Professional Wildeyed Visionary