[comp.unix.internals] Turning off "write extended" on sparc

raja@bombay.cps.msu.EDU (Narayan S. Raja) (10/26/90)

Could some SCSI/Unix/SunOS guru help me
with the following problem:

We have an external SCSI device that talks
to our sparc-1.  It emulates an external
SCSI disk.  

A couple of months ago I upgraded the 
sparc from SunOS 4.0.3 to 4.1.  The
device stopped accepting commands from
the sparc.  (Commands are sent to the device
by doing "write"s to the emulated disk).

So I rolled back to 4.0.3, but the problem
still wouldn't go away!  A clever guy on
the net [jon@amc.com (Jon Mandrell)]
suggested that maybe the sparc was doing
"write extended" instead of "write" and the 
external device could not emulate an extended
write.  I checked it out using a debugger
and it turns out he was absolutely right.

OK, now the question is: can I set some
flag or do something so that SunOS will
use an ordinary write (hex 0A) instead
of extended write (hex 2A)?  My code,
which used to work, has not changed in
any way; so it is the Sun SCSI driver
which is doing it different.  Moreover,
there MUST exist some way to gimmick this
at least under 4.0.3 because it USED to
work under 4.0.3.  Help!


Narayan Sriranga Raja.