Date : Tue, 07 Mar 2006 23:51:28 +0000
From : Fragula <fragula@...>
Subject: Re: Warning: Sad case on list!
Jules Richardson wrote:
> Ahhh yes. Our 570's much like that, with three washing machine-sized CDC
> drives
CDC on a PDP? I thought the twain would never meet... Sounds impressive,
hope you have the aircon to match!
and all the trimmings. The separate memory crate's having an off
> moment
Rust?
> these days (the machine had been stored for ten years totally
> dismantled, unlabeled, and spread across ten rooms, so it's wonder we
> managed to find all the bits at all) but it will run again at some point.
Sounds like heaven. But then I don't suppose you can work the way I like
to (often laying on the floor just staring at something in a trance like
state, muttering under my breath I'm told, until it somehow makes
sense.) I can't work that way at work, (it's "unprofessional" or
something lame like that) but then i don't get much real work done at work.
> They pretty much all were I think; you could wire them for three phase
> but all the ones I've stumbled across have been single phase. Even our
> 570 is and that's big by pdp standards.
FANS! No really. I've turned down a lot of big kit because the blower
motors are 3 phase. the electronics isnt' a deal. Certainly even the
lil 6400s had 3 phase fans.
> Not sure about the DECSystem 10 and 20 machines though as they were
> bigger animals still (no chance we'll ever get hold of one - last UK one
> in commercial hands was removed over ten years ago)
Indeed. There was a big TOPS-20 system where I work now, removed about
that time, though it had been powered down a few years before removal.
the 6400's were its replacement. All gone now. :-(
> On the big pdp front, NATS down at West Drayton had 120 11/34 crates
> chained together doing processing until last year when they dumped them
> all - it was sad to see the big empty room where all the cabs had once
> stood. (we did rescue some nice stuff from them though, and we've got
> more 11/34's than we know what to do with as it is!)
Heh. Use 16 of them to do the fractal calculations, with the beebs on
RS-nnn to front the graphics. ;-b'
>> has some flakey RAM,
> Sounds familiar!
> In the various manuals on bitsavers there should be all sorts of memory
> diags you can load in which can help identify the duff chip.
I've starting writing it. the machine can be forced to start, and the
fault seems to be near the top of RAM (the ROM diags actually give an
address in octal, it's just figuring out where that physically is on the
PCBs. I Somewhere<tm - and by the way its very frustrating sometimes>
have a faq that tells you how to work it out for the boards that I have.
> Oh, that was the other thing... not sure if the Acorn adapter supports
> parity,
uhh.. Don't think it does actually. I'll check the ACB-4000 manual, that
should mention it.
> and lots of drives can't be jumpered to ignore it.
Indeed. And some can't be jumpered to switch it on.. (A Quantum 2 gig
that refuses to work in one of my SPARC lunchboxes for just that reason.
> Blah, we had
> this discussion just a few months back on here and I can't remember what
> the outcome was - and the schematics aren't to hand at the mo to check :/
Ahh. You have GOT schematics.. I won't bother finishing and scanning
mine then..
>> on a BBS. "Old ST-225's dont die, they just get noisier!" (and stiction,
>> but thats fixable.)
> Seem to remember ST225s are really prone to cooking one of the power ICs
> on the board...
Nope.. I've roast a pair stuffed into a single full height bay 24/7
through heatwaves and snow etc. Had 'em so hot I can't touch 'em, and
they still wouldn't die. (Running a BBS, many years ago, and even used
to go on holiday and leave them...) They needed the data bounced off and
a reformat every spring and autumn. Expansion/contraction and consequent
misalignment I suspect.. These are good old steppermotor drives, no
servo tracks!
> You need a Cube Eurobeeb... backplaned beeb goodness :-)
Got one! :-) I even know where it is! Lovely little thing.
Cheers!
M.