[556] in linux-scsi channel archive
Re: Errors & Unit Attention
daemon@ATHENA.MIT.EDU (Harik A'ttar)
Tue Aug 29 12:50:45 1995
Date: Tue, 29 Aug 1995 04:02:20 -0400 (EDT)
From: "Harik A'ttar" <harik@chaos.sub.ucf.edu>
Reply-To: drm89121@pegasus.cc.ucf.edu
To: "Stephen D. Williams" <sdw@lig.net>
cc: "Brandon S. Allbery KF8NH" <bsa@kf8nh.wariat.org>, sdw@lig.net,
eric@aib.com, lnz@dandelion.com, linux-scsi@vger.rutgers.edu
In-Reply-To: <m0sn552-0009yuC@sdwsys>
On Mon, 28 Aug 1995, Stephen D. Williams wrote:
> >
> > In your message of Sat, 26 Aug 1995 15:32:13 EDT, you write:
> > +-----
> > | This is one of those areas that separates a good OS from a great one:
> > |
> > | SCSI can electrically and protocol wise handle hot connection and disconnecti
> > on
> > | of drives, but many OS's (if not most) don't retry operations sufficiently
> > | to handle it.
> > +-----
> >
> > Try it with a PC SCSI device sometime. AHA1542s in particular will freeze
> > solid - the on-board microcode crashes and you have to reset/powerdown to
> > get it back. (I have had it happen.) Most other PC SCSI cards of my
>
> This is one of the reasons that I will NEVER use Adaptec again.
> I've had it do this, and burn out the SCSI fuse, with attempted use
> of 8mm tape drives...
>
> I've had so much better results with Future Domain it's not even a contest...
>
> (Note: most of my SCSI hacking/assembling days was in 8-bit/16-bit era...)
Ahh yes. of course, my machine originated in the 8 bit/16 bit days.
It's been slowly upgraded since. What FD scsi card are you using?
Ive had no problems either, mine is the TMC-1680 (ISA bus) And it works
like a charm. Now if I only had a DAT to test it with. :(
>
> > acquaintance also fail rather poorly in such a situation. (And for the
> > multi-architecture folks: you can destroy an SBus SCSI card by trying to
> > hot-plug devices...)
>
> Really? Shouldn't be, according to my dim memory of the standard.
> I've also seen it done a lot.
>
> > It hardly seems worth catering to a facility not supported by much if any
> > hardware.
>
> I disagree: one of the things that I'm slowly working on is RAID and
> RAID like support built into the kernel and/or device drivers: having
> a kernel that will support hot-swap gracefully and robustly as
> possible is a must!
Ohh! (drooling at the thought of a kernel supported hot-swapable raid
system) That would be a very nice addition right there. :)
Would make all those "linux is not a REAL os" people shaddup...
(Assuming at least some hardware out there will
> support it. One trick often used by the hot-swappable hardware is
> simply to build connectors where either power or a reset line always
> breaks first and makes last.)
Ah, that's a hardware issue. :) Seriously, if they can hack in support
for dos-based hot swapping ISA drives (seen it done) then it shouldn't be
too bad to use it in linux.
> --
> Stephen D. Williams 25Feb1965 VW,OH (FBI ID) sdw@lig.net http://www.lig.net/sdw
> Consultant, Vienna,VA Mar95- 703-918-1491W 43392 Wayside Cir.,Ashburn, VA 22011
> OO/Unix/Comm/NN ICBM/GPS: 39 02 37N, 77 29 16W home, 38 54 04N, 77 15 56W
> Pres.: Concinnous Consulting,Inc.;SDW Systems;Local Internet Gateway Co.;28May95
>
>
chaos@dynamic.ip.don't.reply Guess what? I really _DO_ speak for my
Dan Merillat / Harik A'ttar system. And if you share my opinions,
drm89121@pegasus.cc.ucf.edu you should seek professional help.
