Just when I think you can't find any genuinely old computer stuff in
thrift stores anymore, I come across something that changes my mind.
This weekend it was a beautiful, mint condition Heath H88. Don Maslin,
keeper of the CP/M disk archives, has CP/M for the Heath H89, but
doesn't list the H88. Does anyone know what the difference is between
an H88 and H89? Externally, they look identical except for the badging.
Are they software compatible?
thanks
Kai
<Allison wrote:
<> The uVAX-II
<> offered 1meg of ram on card, FPU and a faster memory interface(PMI)
<> along with denser 1mb, 2mb, and 4mb (and later 8/16mb) cards. This made
<> a 5mb microvax-II possible in two cards instead of 7 using uVAX-I!
<
<AFAIK the MicroVAX I can't do 5MB no matter how many cards you have. It's
<a pure QBus machine; all memory lives on the QBus and there is no
<scatter/gather map to allow it to get to more memory than the QBus can
<address, which is 4MB.
Right you are. But in the context of what I said, you see that 5mb uVAX-I
was difficult for power and bus space reasons as well... the fact that
the microvax-1 didn't not have PMI(over the top memory connect) and Q22
could not address more than 4mb was just one more limitation. What happend
in real world cases is the total load on the power supply was way to great
or you ran out of slots!
The one I ran for a while back in 86 at DEC was 2meg running microVMS.
That box was full! 2 quads for the cpu, 2 quads for the memory, 1 quad
DHV11, 1 quad RQDX2, 1 dual for tk50, 1 dual for DEQNA, 1 RD53. The power
supply on that one ran at 95%. It was slow but I was one of the few with
a vax under my desk!
ONE ITEM: BA23 boxes have a cable from the power supply to the backplane.
There are two different ones. There is one with variable length wires that
looks neat and tidy making the bend. That cable is bad news! It was ECOed
back in the late 80s as the +5 and ground are parallel lines! The cable had
different length leads and the shorter ones having lower resistance would
hog all the current. This would cause a serious overload of the connector
pins with resulting is possible destruction of the power supply and
backplane. This would occur at less than rated load! The correct cable
has ALL of the wires the same length to circumvent this problem. The revised
cable was tested at 200+% of rated load and did not exhibit the failure
mode. So if you playing with MicroPDP-11s or VAXen in the ba23 box check for
that flaky cable and replace it if possible or at least check it for signs
of overheating at either connector. It's molex pins and if not damaged the
connector bodies can be reused.
Allison
Hi!
I have a lead on a computer, a Burroughs 6800, that is apparantly being
kept in a store-room and not being used. It seems I should be able to get
it if I asked. My question is - do I want it? Mostly I have limited
myself to micros, as they are small and fit my own interests, but I have
always been willing to accept larger systems. But as a result I know
nothing about Burroughs - is this thing huge, or what? Is it rare, common,
powerful or just dull? Any information would be greatly appreciated,
especially where it fits into the general history of computers.
Thanks heaps,
Adam.
Allison wrote:
> The uVAX-II
> offered 1meg of ram on card, FPU and a faster memory interface(PMI)
> along with denser 1mb, 2mb, and 4mb (and later 8/16mb) cards. This made
> a 5mb microvax-II possible in two cards instead of 7 using uVAX-I!
AFAIK the MicroVAX I can't do 5MB no matter how many cards you have. It's
a pure QBus machine; all memory lives on the QBus and there is no
scatter/gather map to allow it to get to more memory than the QBus can
address, which is 4MB.
Roger Ivie
ivie(a)cc.usu.edu
> From: adam(a)merlin.net.au (Adam Jenkins)
>
> I have a lead on a computer, a Burroughs 6800, that is apparantly being
> kept in a store-room and not being used.
Adam,
The Burroughs 6800 is a large mainframe. It will require 208-220v
3-phase power and probably air conditioning. I suppose you probably
don't want it.
Burroughs machines are rare, especially one this old. Burroughs had a
policy of taking back their old machines in trade, which they would then
destroy to avoid having used machines in competition with their new
ones. It is an interesting machine historically, although possibly not
the most interesting in the line which is now called the A-Series.
Probably about the first in the line was the B5000. The famous early
machine was the B5500, there was one at the University of Wisconsin and
it was about the first machine I ever used. I remember one of the UW
professors contributed to the 6800 architecture (suggestions, at least)
and there was a big fuss about whether to get it or a Univac. They ended
up with the Univac 1108. The 6800 was to have been a big improvement
over the 5500 but was quite late or something.
The A-series computers are stack machines. Its a very interesting
architecture. At the time of the B5000 series it was considered ahead of
its time, but now that architecture is essentially dead. The most recent
new stack machine I know of is the original HP 3000 minicomputer from
the late 70's early 80's. It is inherently difficult to get a stack
machine to run very fast, like today's superscalar microprocessors. But
a stack architecture results in small code. The virtual machine for Java
byte code is a stack architecture.
There are a number of other historically and architecturally interesting
things about the Burroughs A-series line and probably the 6800 in
particular. If you remember TRON, the evil "MCP" gets its name from the
Burroughs operating system (Master Control Program.) There is a
Burroughs thread running at the moment in alt.folklore.computers.
Please find out if its just the machine or if there is documentation
and/or software. I would like to see the whole machine saved, but if
that turns out to be impossible at least maybe good docs can be saved.
Ideally there would be hardware manuals including user reference manuals
and schematics, diagnostic software and manuals, operating system and
application software and manuals. Possibly if the closet contains only
the machine other folks may have documentation in their office.
If you don't want it I would be very interested, but if you are in
Australia it could be very expensive to haul it back here. Please keep
in touch and let us know what you find out.
Paul Pierce
http://www.teleport.com/~prp/collect/
I know someone locally who's trying to sell a complete boxed Commodore
Plus/4 for $25. If anyone's interested I'll hook you up with him.
Sam Alternate e-mail: dastar(a)siconic.com
-------------------------------------------------------------------------------
Computer Historian, Programmer, Musician, Philosopher, Athlete, Writer, Jackass
Attend the First Annual Vintage Computer Festival
See http://www.siconic.com/vcf for details!
I spent the morning at an auction and got the following;
1. IBM Powerstation 320 with a 19' monitor 6091-19 with cable (3 BNC),
anyone having some info this unit I could use it. Can't get it to show
anything on the monitor. All lights are on.
2. IBM Powerstation 220 with 17" monitor this unit is locked in service mode
and I did not get a key. Any info this one would be great.
3. MAC LC III with full display monitor unit works and is loaded with software.
4. MAC SE FDHD works great and is also loaded with software.
5. Apple TechStep testing unit with case, manuals, software, and cables. Now
I really do some unit testing.
6. About 10 very large boxes full of IBM PS/2's and other parts. I have
very busy weekend with these boxes.
well that's it. see ya
The floppy drive incidently, works on other c64's just fine, and I have
cleaned and calibrated it.
----------
> From: jpero(a)mail.cgo.wave.ca
> To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
> Subject: Re: Sick C-64c
> Date: Monday, September 08, 1997 4:38 AM
>
> > Date: Mon, 8 Sep 1997 08:22:06 -0500
> > Reply-to: classiccmp(a)u.washington.edu
> > From: "Bill Girnius" <thedm(a)sunflower.com>
> > To: "Discussion re-collecting of classic computers"
<classiccmp(a)u.washington.edu>
> > Subject: Sick C-64c
> > X-To: "Classic" <classiccmp(a)u.washington.edu>
>
> > I recently aquired a stack of c64's, these are the old brown type. Of
(4),
> > One works fine, 1 boots, and can run catridges, initializes the floppy
on
> > boot, but can never access it after boot, the other two have power but
no
> > video. Any ideas on these folks?
>
> Checkerboard or no display usually means memory is bad, replace all
> 64k ram chips.
>
> Oddball problems usually traced to the VIA ic's blown by unbuffered
> lines. Real easy to do to blow it if careless!
>
> Make sure you put the shield back on with those finger "pads" coated
> with bit of heatsink paste on them, they're like poorman's heatsinks!
> The video IC get brutally hot!
>
> Monitor the voltages for stablity and good idea to replace those big
> capacitors just in case. The floppy drives I think is belt driven
> type and needs bit of cleaning. I had a problem with one, inside
> that small can there's 2mhz crystal and one TTL chip, That TTL chip
> was baddie.
>
> Jason D.
> From: Greg Mast <gmast(a)polymail.cpunix.calpoly.edu>
> > Subject: Re: FS: Mac Plus
>
> > 20 of them just got trashed, but if you want a couple I'll be stopping
in
> That's amazing! 20 computers probably worth at least $25 each tossed in
the
> dumpster? What a waste! $500! Mac plusses are really still good machines.
I
> managed my business using Excel, Word and quicken on one until a couple
years
> ago (until I sold the business). The local shop here parts them out for
repairs.
There are regular wanted ads in Austalian newsgroups from a guy who turns
them into fishtanks. Apparently a whole bunch of people do this.
> Date: Sun, 07 Sep 1997 08:39:09 -0500
> From: "John R. Keys Jr." <jrkeys(a)concentric.net>
> To: classiccmp(a)u.washington.edu
> Subject: Re: FS: Mac Plus
> 20 of them just got trashed, but if you want a couple I'll be stopping in
> the shop later this week and if they have a new batch in I will pick you up
> a couple. We can settle up after I get them. They also have alot of SE's,
> 512's, and sometimes the 128's. There is also a thrift store here that
> sells all computers for 80 cents including taxes. Everyone has started going
> here and it's getting harder to catch any good machines there. If anyone
> reading this is looking for HP stuff let me know as I passed on a complete
> HP3000 for $10.
That's amazing! 20 computers probably worth at least $25 each tossed in the
dumpster? What a waste! $500! Mac plusses are really still good machines. I
managed my business using Excel, Word and quicken on one until a couple years
ago (until I sold the business). The local shop here parts them out for repairs.
I did see our goodwill toss a Radio Shack Model 4P(??) and an Osborne the other
day alond with a pile of PC Jr's and Commodore stuff. I almost grabbed them
until I remembered I have a pile to get rid of and no time to play with them.
Every Friday they clean (dumpster) the electronics section.
