From: drew@ophelia.cs.colorado.edu (Drew Eckhardt) Subject: Re: SCSI drivers Date: Mon, 17 Aug 1992 07:09:11 GMT
In article <1992Aug15.195737.20833@aoa.aoa.utc.com> moose@aoa.aoa.utc.com (Bruce Trvalik) writes:
>I've checked most of the FAQ's but I have not seen any information on drivers
>for the Adaptec SCSI 1522 adaptor for one of the "low" cost PC unixes. Does a
>driver exist?
No.
>how hard would it be to port one?
Port implies that one exists for some other platform, to my knowledge there
is no freely available driver source for the 1522.
You'll have to write a lowlevel driver to control the 1522, and will
probably be drafted to fix it when version 2 of the SCSI drivers are
finished and debugged, which will happen when I'm less busy and
otherwise "RSN".
As far as difficulty : Not as easy as a nifty-whiz-bang intelligent
board, but not as bad as with the Seagate which only handles half of
handshaking and arbitration for you, and only interrupts on the SEL
received when you RESELECT.
Basically, you need to know how to get SCSI commands/data to / from the
devices, and how to detect if the board is in the system. The
generic parts of the SCSI code take care of the SCSI part for you,
which means you can pretty much write a driver with register
descriptions, etc if you have an intelligent card.
If you have a dumb board, like the Seagate, you will need to pick up
the SCSI standard as recreational reading, and have enough of an understanding
of the standard and what should be happening to make the card
do what you want. The SCSI standard was written by a comittee of
engineers, isn't light reading, and you run into little things that
are perfectly legal, that you didn't think of and didn't see
in your drive's implementation. These little things will scramble
blocks, etc, and make your life miserable - like the Seagate problem with
save / restore pointers that affected disks that disconnected between
sectors in a multi-sector read. Perfectly acceptable according to the
standard, but I didn't see it in my hardware, and never caught the
bug (Thanks WDE!)
I don't know very much about the Adaptec product line, and would
suggest that you get docs from some one on the board, and then decide
how much trouble it will be for you.
-- Microsoft is responsible for propogating the evils it calls DOS and Windows, IBM for AIX (appropriately called Aches by those having to administer it), but neither is as bad as AT&T. Boycott AT&T, and let them know how you feel.