Re: KA410 Boot Failure With TKZ-50

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sat, Jun 13, 2020 at 10:29:06PM +0000, Josh Moyer wrote:
> 
> I wasn't asking if I should implement TMSCP, but rather whether my hardware
> and firmware do.  I have a hunch that booting from MUA0 is breaking because
> of the SCSI board in the TKZ-50, but I can't be more specific and could
> easily be wrong -- it's just a hunch.

This seems very unlikely.

The TK50 hardware implemented neither TMSCP nor SCSI.  It implemented a
very minimal proprietary protocol over a very, very slow serial connection
(200Kbit/sec) to one of two possible controller cards: the SCSI TKZ50 or
the QBus TQK50.  An 80186 (I think; might have been an 8085) on the
controller card interfaced to one of the two possible host buses.

Unless your machine has Qbus slots, it's not going to be expecting to talk
to a TMSCP TK drive.  And if you have a KA410, you don't have Qbus slots,
you have a MV2000/VS2000 just like the one they plunked down on my desk
on my first day at work at DEC in 1990 (they'd ordered me something nicer,
but it didn't show up for several months).

I booted and installed Ultrix (probably 3.1) on that machine from a TK50
connected with a SCSI cable, so you ought to be able to do what you're
trying to do.

That said, the TK50 hardware was OK but the tapes themselves did not
have a stellar reputation for durability, so you may have trouble finding
media good enough to use, at this point.  For years I had personal files
backed up on TK50 so I kept an old DLT drive with DEC firmware around to
ensure I could read them; I threw the DLT drive out when the TK50 tapes
degraded so badly they would no longer read.

Thor

P.S. Here's something I can't remember, quite.  The KA410 also has an
onboard controller for an ST506 hard drive.  Does _that_ emulate MSCP?