[rescue] WTB: Good 'antique' computer for education

[BSD Bob the old greybeard BSD freak]

> My fiance is looking for an OLD computer to teach herself some 
> computer architecture.  I'm thinking something with a card cage.  My 
> personal favorite are the VME based sun machines but I'm open to 
> ideas.  I need something where she can get replacement parts cheaply 
> and (relatively) easily.  Would a VAX be good for this?  What about 
> an -11?  How small can I make an -11 or a VAX?  Does anybody have 
> anything they would be willing to let go or a place to get this kind 
> of stuff?  (I wouldn't mind getting a VME sun... Especially not an 
> 4/xxx deskside one)
> daniel

I have some minor thoughts on the subject....

A PDP-11 is fun, but finding working bits for them can be a problem.
I would hesitate to recommend one for a person just wanting to play
on an old machine, unless you also were ready to become a hardware
techie on it, too.

VAX and Sun VME are both good.  The only real problems you have with either
are those gawdawfull tape things (TK50 on VAX and DC600 on Sun).  Tapes
are somewhat of a pain to find on VAX, and all the capstan rollers are
decomposing on QIC tape transports for Suns... no joy.  I have gone through
about 2 dozen Sun compatible tape transports and those silly capstan drive
wheels decompose into an ugly goo, after just a little bit of use, rendering
the transport unusable.  I really would stay away from those QIC things of
the 60mb vintage, unless you wanted to do a lot of transport servicing.
Replacement capstan wheels are absolute unobtainium, but rubber hose works
if you can find something of similar dimensions and superglue it in place.
It is a pain in the ol' whatskies, to do well, though.  It might be possible
to swap a 150mb transport motor and capstan, but I have not checked that
out at the electronic level, yet.

I have run both VAXen and VME sun3/sun4 crates for about 5 years, now,
and would hedge my bet on the VAXen, for sure.  Besides you can run all
the ancient unix stuff on VAX, while sunstuff can be hard to find, although
it is available in certain archives.  I always thought SunOS-3.5 was a nice
OS, but SunOS-4.1.1U1 is what everyone uses.  OldSunstuff has scsi problems,
while the VAX stuff always just works, in my hands.  I can barely get up
3 drives on a VME Sun scsi bus, without the bus taking a dive, while I can
always get 7 drives up on a VAX scsi bus, no problem.  I used to love old
VME sunstuff, but am beginning to hate it for the above reasons.  Opening
the cases to replace tape transports is a real pain.  Replacing tape
transports (or HD's for that matter) on a VAX is significantly easier.
If you don't need great drive space, then either is fine.  But, if you
want a lot of scsi playspace in the old gear, go VAX, for sure.

You need to keep in mind that VAXen are geared towards cmdline terminal
modes, while Sunstuff runs cmdline or gui modes well.  If you want a
gui on VAX, you have to run Ultrix, for now, although some X support
is available on certain VAX machines in NetBSD.

An MVII in a ba123 case with an mfm or esdi controller for really old
stuff or a scsi controller for more modern stuff would be good.  It
is slow enough that you can take a vacation while you compile the system.
I run Ultrix 32m on an mfm box, and 4.3BSD Tahoe on an esdi box.  My scsi
boxes mostly run NetBSD, but sometimes some Ultrix for the fun of it.
The old unices run on the mfm/esdi controllers quite well, but I have
not seen one with working drivers set up for scsi, yet.  A faster cpu
like one of the MVIII cpus speeds things up a bit.

A VAX 4000/200, is a pretty zippy medium-sized thing, that looks kindof
oldish, but runs fast enough to be usable.  It only runs NetBSD, and
maybe OpenBSD, though.  One might could backport 4.3BSD to it.  It is
the fastest of the Qbus VAXen.  But, you need to find a Qbus scsi
controller for it, since its native dssi controller is not yet supported
on anything except VMS (yuk!).

A Sun 3/260 might be one of the better VME suns.  A 4/260 is probably
easier to work with, and the scsi is a little better, but it may be
harder to locate, and it is more limited in working OS's.  If you
wanted to be really cool, and could find one, one of the big 3/xxx
datacenter things might be fun and impressive.  I have not had the
fortune to run across one of those, locally, yet.

If you have the space and can feed power enough to it, a VAX 11/750
or 11/780 might be fun, too.....(:+}}...  I have always had eyes out
for an 11/750, but nothing like that ever surfaces around here.
They run the ancient unices and NetBSD, quite well.

I have several Sun VME crates if you want one, but you have to come
by and pick it up (central NC).  Too much to ship, for what they are
worth.  One is a 3/160, one a 3/260, and one a 4/260.  I will probably
never go back to using them.  They are just too much of a pain, compared
to the joy of a VAX.  I will be working up a 670MP, though....(:+}}...
for some relatively heavier slightly more modern Sun VME iron.

I know, I be speaking a tad o' heresy, about VAXentoyz on the rescue
list, but, I have not had good karma on the old VME sunstuff, to date,
except for my 4/260, which does a pretty fair job.  All my later
sunstuff does fine, but I don't have much hair left to pull out over
the old VME stuff, anymore.... grumble, grumble, mumble...(:+{{...

Whew! Enuf said!

Bob