🚀 go-pugleaf

I have recently experienced extended problems with the Exabyte tape drive.
We have attached the Exabyte drive to a Sun3/260 with a SCSI-2 (sc) host
adapter.  We are running SunOS 4.0.1 and after completing installation of
the drive, we were unable to access it.  The host adapter would return an
I/O error and the device controller would return a mode select failed
error.  After going through all the standard checks (4.0.1 SCSI patches
removed, replaced X60 backplane adaptor, etc.) we suggested to Exabyte
that they might have a problem with their device driver.

Exabyte responded by examining their device driver software and suggested
that we may have a PROM on the tape drive initialized improperly.  They
described to us the proper sequence for resetting this PROM and (at long
last) we have a functional Exabyte tape drive.  

This PROM can be reset by running adb on /vmunix and querying the variable
st_ex_MX4_23.  After saving a copy of the working kernel, the command
sequence is

	adb -w /vmunix
	st_ex_MX4_23?W 0

The query should return 0x1 and then reset to 0x0.

I'm indebted to both Michael Couch and Bob Wagner of Perfect Byte, Inc.,
for all their help.

					Steve Carr @ Icad