An interesting 3 hours on PBS last night:
- 'Steve Jobs - One Last Thing': No description necessary.
- 'Long Distance Warrior': McGowan/MCI's David & Goliath battle with AT&T
and disastrous merger with Worldcom.
- 'Digital Man/Digital World': Ken Olsen/DEC's growth and ultimate decline.
(No doubt everyone here except myself had already seen this one ;-)
Interesting comparison of the different styles and personalities of three
men who profoundly influenced the tech world of today and their companies.
Thoroughly enjoyed it.
This might be a tempest or shielded vaxstation? Anyone speculate or
know for sure.
The vendor may have these mixed in as equivalent to their other
vaxstations. If you search for "DEC vax VS42A-BN"
you end up back at the vendors listing for the ones with plastic
covers. I didn't turn up any info yet, not hoping to.
but the thing has what appears to be optical, and a huge connector which
may be shielded SCSI on the back.
I can't tell from the front, but there may be a hatch to allow it to be
opened and a floppy inserted, not sure from
Kind of an interesting device.
I looped back into the vendors listings to this auction for the plastic
topped version, by the way
It is badged VT-1300 so may not be a vaxstation. And the other box may
be one of the VT-1300's
that is tempest or shielded.
I bought the Tek 4051 on ebay today; Jason brought it to my house and it works perfectly, with about a half hour of programming instruction my 12 old daughter was plotting a cat face.
I would like to get in touch with other users of this first personal computer, and find additional resources.
Do you know where I can find an archive of BASIC programs for this?
Has anybody built plug in cards in the back, mine came with a realtime clock and a "file manager", I do not know what that one does.
I have some Tek scopes with IEE-488, and I will see if I can get the IEEE interface working.
There was a DC300 tape in the machine:
The belt is broken in the tape, I have ordered some new DC300's and will transplant the tape.
Any resources will be welcome!
Then why not use a dip compatible version of the DS chip? I mean yes this allows for switchable battery which is very nice but SMT soldering is not for everyone.
I wonder if there is a way to determine if there will be BIOS issues by switching the DS12887?
-------- Original message --------
From: Jon Elson <elson at pico-systems.com>
Date: 1/22/17 9:16 AM (GMT-08:00)
To: General at classiccmp.org, "Discussion at classiccmp.org:On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
Subject: Re: DS12887 pcb substitute with battery
On 01/22/2017 10:07 AM, Ali wrote:
> I thought the problem with switching these chips was that part of the ROM code was embedded in them? I.e. it isn't just an issue of battery? Am I wrong? If I am then why not use one of the replacement chips that are available?
These don't have a lot of memory on them.? many early PCs
stored some config info there, but generally the BIOS can
reconstruct it if it isn't there.? I suppose there is a
possibility that random data in the CMOS memory could cause
the BIOS to try to use unavailable features and hang.? I
don't think anybody put actual executable code in there.
<From: tom sparks <tomasparks.ts at gmail.com>
<I want something that has anti-procrastinate features (no internet, no
<videos, no mp3s, etc),
<long battery life (40+ hours),
<easy replaceable batteries
On all of your points, I would recommend the HP LX200. I have one and carry it with me every day.
Runs MS-DOS 5.0 on two AA batteries (alkaline or rechargeable) for months (literally).
VT100 emulation is built-in.
You can get them on the internet (they even have been used as a web server), but you will want to use the PCMCIA slot for a RAM card, rather than a network card.
Many users like the keyboard: it is easy to thumb type on it, and it has a full number pad -- it was designed as a portable Lotus 1-2-3 computer.
You can get versions with a double-speed crystal and internal RAM up to 64 MB.
There is still an active user community, repair services available in the US and Europe and thousands of programs available.
The main problem is that the plastic at the hinges has a tendency to crack, but that often can be repaired.
IBM invented computer emulation and introduced it with System/360 in 1964.
They defined it as using special-purpose hardware and/or microcode on a
computer to simulate a different computer.
Anything you run on your x86 (or ARM, MIPS, SPARC, Alpha, etc) does not
meet that definition, and is a simulator, since those processors have only
general-purpose hardware and microcode.
Lots of people have other definitions of "emulator" which they've just
pulled out of their a**, but since the System/360 architects invented it, I
see no good reason to prefer anyone else's definition.
The Personal Computer Museum (http://www.pcmuseum.ca) is
offering a beautiful 2018 vintage computer calendar as a fundraiser. The
calendars are in hand and the cost is $20 Canadian (no tax).
shipping rates (in CAD) are $3.50 within Canada, $5.00 to the U.S. and
$10.50 to the rest of the world.
We accept Paypal via our website at
If you don't like Paypal, e-mail me
directly for other options!
The order page includes a sample of what it
The computers included this year are:
IBM PC (1981), Kaypro
II (1982), Pencil II (1984), Exidy Sorcerer (1978), Commodore PET 4032
(1980), Apple ][+ (1979), Apple PowerBook 150 (1994),
(1982), NeXTcube (1980), Superbrain QD (1979), Atari 800 (1979), Unisys
If you are interested please reply here or to
info at pcmuseum.ca .... The quantities are limited.
Thanks for your
> From: Jon Elson
> I'm not sure the original DEC PDP-10 (KA-10) used microcode
No, it didn't; in part because it pre-dated fast, cheap ROMs (the development
of which was a considerable task in the /360 project - the wonderful "IBM's
360 and Early 370 Systems" covers this is some detail). The KA10 is built out
of FLIP CHIPs which carried individual transistors.
Another fun KA10 fact: it used 'hardware subroutines' - i.e. a clock pulse
would get to a certain point, and get conditionally diverted through some
other circuitry, later to come back and continue where it left off. Whee!
I've been trying to figure out what is wrong with the 12V rail on my
H7861 (BA11-S) power supply. It's showing about 4.2V. The 5V rail is
Page 39 of the following schematics is the main part board of the PSU.
Going into the collector of Q3 is about 80V coming straight from T2 (I
think I measured it at about 100Hz), but the emitter is putting out the
4.2V, which is the same as the base voltage and output voltage. I tried
replacing this transistor because the hFE was about 80 and a good one
was about 120. Unfortunately it didn't do anything.
None of the capacitors look swollen and I don't see any leakage. There
is a smaller board which I think goes into J4. The 12V side seems to
have a 555 timer and adjusting the pot doesn't change the voltage at
My understanding of switchmode power supplies is very poor. Does anyone
have some pointers on what to check or what might be the possible cause?
Hopefully I can get my PDP up and running again... Only got about 20
minutes use out of it.