HP/DEC/Compaq

So I have an HP 9000/350 running HP-sUX 08.00. It came with a sticker on the 670H hard disk saying "Homer" and a Homer Simpson squeeze toy. So that's its name. This is homer: http://www.floodgap.com/iv/1572

Although the 670H hard disk is a freaking tank and will probably never die short of a head-on missile attack (gawd, HP sure doesn't make computers like they used to), I wanted a bootable tape as a recovery method since I don't have HP-UX media (except for the C8000). After a lot of watching on eBay, I finally landed a 16-track HP 9144A tape drive.

The 9144A and 9145A drives are interesting in that they use QIC form factor tapes, but they have to be pre-formatted as IOTAMAT at the factory (DC 600HC tapes are the 3M equivalent). They can do error correction and slow random access; in fact, HP-UX treats them as very slow CS/80 disk drives. The 350 will boot from it, which is ideal, and I even have some HC tapes lying around. Perfect!

The first problem is that HP used a polyurethane-isocyanate composite for the pinch roller on the capstan that degenerates into black gooey muck over time. I had expected this, but I hadn't expected it to have already leaked over parts of the drive. That was an extensive cleanup (I discovered 91% isopropanol dissolves it well, which was good because that's what I was using to clean the head and the rotation sensor). Then I had to rebuild the capstan roller; for that, I selected a 9/16" ID - 3/32" wall rubber O-ring and glued it to the capstan with Loctite GO2 gel, which I picked since it has a space-filling vinyl-silicone formulation that seemed able to take more compression than regular epoxy. It cured for 24 hours. I thought that came out rather well: http://www.floodgap.com/iv/2354

I powered it on; the rear electronics said "P 2" (self-test passes, HP-IB device 2, which is correct). I inserted a brand-new 600HC tape as a positive control. The new drive wheel gripped perfectly and moved the tape properly; the BUSY light came on and it spun through the tape and found its format keys, and turned the BUSY light off. I pressed Unload, it rewound the spools, and I ejected the tape successfully. No residue on the tape, so I concluded the positive control was a success. The negative control was a regular DC 6150 I had in a box. I put that in, the drive put its BUSY light on, spun the tape, buzzed a few times, and illuminated FAULT . That was as expected. I ejected the tape, confident that I had proven both the electronics and the mechanism were now working, since it could read and certify its own tapes, and properly rejected unformatted QIC tapes.

The second problem I haven't been able to solve yet. SAM did not see the tape drive when I tried to install it, so I manually did so with mknod (major 4 for character and major 0 for block; minor 0x070200 for slow HP-IB bus and device 2). When I order the drive to accept data with tcio, it stops with a write error. When I try to have tcio certify the tape with tcio -uv, it says it fails. The drive does light BUSY and tries to write but invariably is unable to do so.

Any suggestions? Clearly it can read, or it would have rejected the IOTAMAT cassette. I see only a unified read-write head on the mech.

maybe the write-protect sensor is stuck?

I hadn't thought of that, though it has a Protect light that should have illuminated. But that's a good suggestion to verify. I'll do that this week, thanks.