🚀 go-pugleaf

I have a quantity of 60 mbyte 1/4" cartridges which I wish to read,
and copy the data onto a CDR for posterity. Unfortunately, my gear
doesn't quite work ...

1 x Linux box (2.2.17 kernel)
with 1 x AHA1542CF SCSI controller (ISA, very old one, 50-pin centronics)
with 1 x Centronics DB50 to old Sun type (50-pin, 3 rows) cable
1 x Sun 3 shoebox
containing 1 x Emulex MD21 SCSI-to-ESDI card
and 1 x 1/4" 60 mbyte cartridge drive. No other SCSI devices.

I remember the ESDI disk used to go in the bottom of the shoebox,
and the MD21 did the SCSI-to-ESDI mapping so the Sun3 box could
access it as a SCSI disk.

I don't remember whether the MD21 drove the tape also.

In configuring the AHA1542CF, I had to turn off Fast SCSI (quite
understandable considering the age of the gear it is driving). Also
the cable isn't terminated, not sure whether this is causing
further problems. Can't find my old Sun3 terminator.

When I boot Linux it recognises the controller and spends a long
time to identify 2 (yes!) SCSI disks, at id=1 and id=5. Both the
MD21. Now interestingly there aren't any disks there at all. It
can't see any tapes. When I use the AHA1542 BIOS diagnostics the
controller sees the MD21 on id=1 and it pauses on id=5, but does
not recognise a device on it.

Now on the kernel side I note that drivers/scsi/scsi.c has the
Emulex in its blacklist to prevent multi-LUN scanning. I seem
to recall the MD21 can actually map 2 ESDI disks; don't recall
whether they appear as 2 separate SCSI ids.

Theories:
	- the tape drive is too old to obey the identification protocol
	- the unterminated cable makes the comms dodgy
	- my AHA1542CF is too old to recognise the tape drive
	- the MD21 is not needed and is confusing the issue

I'm about to go and pull the tape unit apart to see whether I do
actually need the MD21. Does anybody have any other ideas? (apart
from borrowing a working internal SCSI drive).

Nick.
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