I managed to bring another one of my supercomputers back to life: an Intel iPSC/860. This one has 16 compute nodes, 8 i860?s and8 i386?s with Weitek co-processors, as well as 4 I/O nodes.
Detailed writeup here: http://www.vaxbarn.com/index.php/42-repair/756-ipsc-860-repair
Downloads (documentation, tape and floppy images available in the downloads section on my website.
Camiel
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Does anyone have a mirror of the terminals wiki at https://terminals-wiki.org?? It seems to have gone dark over a year ago, and it would be a shame to lose the resource.?
If there is no mirror, does anyone know of a way to contact the owner/maintainer?? I'd like to see if there's anything I can do to help get it back online.
Thanks,
Dave
Working on restoring my very first computer, an Apple II+. Got it mostly
working with just a couple of issues identified at the moment. Some of
the keys on the keyboard don't register but I can work on that. The real
question I have is about the video, it constantly rolls and no amount of
playing with the vertical hold on any monitor I try will completely stop
it. I can get it close but it will slowly roll one way or the other at
best. Tried several different monitors and it is the same on each. Also
tried my old Apple IIe and it seems fine on all the monitors so trying
to decide what might be the issue with the II+. Any ideas or areas to
look?
Thanks.
David Williams
www.trailingedge.com
Folks,
Does anyone have a design for printing card handles for QBUS / UNIBUS
cards? It seems a natural application.
Some grepping of the list logs, a brief plonk through the gadawful
thingiverse search, and various googling have produced no existing
designs.
Thanks,
De
Hi All,
I have two Maxtor XT-4380E drives, one is a Series Code 3 and the other is
4. Is it OK to swap the boards between the two or is this a bad idea? They
physically appear to look the same.
Also a general question about PCB cleanup. Is there a method or solvent of
some sort to clean boards? I've always used 99% alcohol in the past.
-Kurt
> From: Paul Koning <paulkoning at comcast.net>
> Message-ID: <9D8BADA7-B597-42E1-99C8-4CC751F838C5 at comcast.net>
> Another part of the puzzle was figuring out how to feed 100 watts of power to a chip,?> and get rid of that amount of heat, neither of which were anywhere close to what was
> done at the time.? I still have some of the tech reports that describe that piece (and I?>contributed a wild idea -- which unfortunately DEC didn't get around to patenting?>before the project was shut down).
Back in the mid-90s, there was an outfit in Britain which made some laptops using Alpha processors.? There was a rumor inside DECin the same time-frame about DEC engineers prototyping an Alpha-based laptop (which never made it to market).
The rumor included the internal code-name... "BURNS".
Dick
On Friday, May 7, 2021, 11:07 CDT,?Zane Healy <healyzh at avanthar.com> wrote:
> These if I needed OpenVMS on a laptop, I'd simply run it via emulator or virtualization?> (not an option for Itanium).? I gather that at least some development on OpenVMS 9.2
> is being done on VM's running on the developers laptops.
Well, the latest version shipping from Bolton is V9.0-H, which has the long-awaited support for VMware, and IIRC some non-zero number of compilers available.? It's still pretty well set in the "bleeding-edge" field of software though.? It's labelled as V90EAK, with the last three letters indicating "Early Adopters' Kit", and made available to a rather small number of VMS customers who are interested in making their own products run on X64-86 platforms (as well as work properly on Itanics running v9.x)
I don't know whether VSI has any particular policy about making the field test kits available to hobbyists/end-users quite yet.? Bear in mind that there's a LOT of VMS components which aren't really ready to use yet.? If memory serves, the V9.1 kit will also be labelled as 'field test', but will be made available to a larger number of customers/test sites, and is expected to include working versions of the components currently 'in progress'.
Regards,Dick
On 5/8/21 12:00 PM, cctalk-request at classiccmp.org wrote:
> Message: 8 Date: Fri, 7 May 2021 21:59:08 +0000 From: W2HX
> <w2hx at w2hx.com> To: Andrew Back <andrew at carrierdetect.com>, "General
> Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
> Subject: RE: 400 Hz Message-ID:
> <de37431b96cf4c82ba5ddb2b9daf1873 at EXBE015SV3.NA02.MSEXCHANGEOUTLOOK.COM>
> Content-Type: text/plain; charset="utf-8" I will add that aircraft are
> one of the main users of 400 Hz. This is because weight is always an
> critical design consideration. So with smaller transformers, smaller
> capacitors, etc, you can save a LOT of weight on electronic devices in
> an aircraft. 73 Eugene W2HX -----Original Message----- From: cctalk
> <cctalk-bounces at classiccmp.org> On Behalf Of Andrew Back via cctalk
> Sent: Wednesday, May 5, 2021 11:26 AM To: cctalk at classiccmp.org
> Subject: Re: 400 Hz On 05/05/2021 16:07, Grant Taylor via cctalk wrote:
>> Were the higher frequencies used because it directly effected the
>> amount of time / duration in (fractions of) seconds between peaks of
>> rectified (but not yet smoothed) power?
> Haven't read the rest of the thread and so at the risk of being profoundly wrong... Benefit of 400Hz mains is that transformers can be much smaller. Think of switching power supplies that rectify to DC and then switch up into kHz, which are then able to use far smaller transformer cores than an old linear PSU. At least this is a key motivation with 115V/400Hz 3-phase aviation power AFAIK.
>
> By coincidence we've just built a big 28VDC power supply, so that we can run a vintage 400Hz aircraft rotary inverter, which will then be used to power up old mil surplus kit that wants this. A classic adventure in yak shaving. Anyway, here's the 28VDC bit.
>
> https://www.rs-online.com/designspark/constructing-a-high-current-28v-dc-po…
That's a very neat repackaging of the Lambda power supplies! Do they
have the surge capability to start that rotary inverter (which may
require a LOT more than 44 amps until the armature gets moving)... I
hope you tested them first ;)
I bought a 1 KVA 115V 400 Hz supply, a PP-7482/G from Fair Radio back
when they still had them ("Reparable") a few years ago. The H-bridge
TO-3 transistors were all blown, some with holes melted through their
lids. I replaced them with BUX48A parts and it works again. It really
sings that A-flat though ;)
But I don't have anything to run with it! When I was young, 400 Hz
surplus gear was a dime a dozen because no one had 400 Hz power. Now I
do and all that gear has disappeared...
-Charles
WB3JOK/0 since '76 :)
I have found the Motor Generator thread to be fascinating and
enlightening. But it has made many a reference to the 400 Hz or other
frequency much higher than mains line frequency. Despite the comments
about the frequency, I'm still confused as to why the higher than mains
frequency was used.
Were the higher frequencies used because it directly effected the amount
of time / duration in (fractions of) seconds between peaks of rectified
(but not yet smoothed) power?
I ask because it seems to me like the percentage of time / duty cycle of
raw rectified but not yet smoothed) power would be the same at any and
all frequencies. Is this assumption / understanding correct or
completely off the mark?
A few different people made references to the amount of capacitance
needed at 400 Hz et al. vs 50/60 Hz mains frequency. Someone even spoke
about high power DC being produced by polyphase converters and the
possibility to tweak tweak winding voltages in order to possibly do away
with the need for capacitors.
Am I starting to understand the motivation behind the 400 Hz or is there
something else behind it? Is this really playing to the (dis)charge
time of capacitors in between peaks of rectified (but not smoothed) sources?
Aside: I started a new thread for this very specific minutia to not
mire the other Motor Generator thread down.
Thank you for all the comments and those who respond to help me learn
something new today. :-)
--
Grant. . . .
unix || die
First, thank you to everyone who replied and gave me things to think
about and learn from.
On 5/5/21 9:26 AM, wrcooke at wrcooke.net wrote:
> Hope this helps.
Yes, indeed, very much. Thankfully, your description happened to mesh
with the weird way that my brain processes things and your message just
clicked confirming what I was learning but still processing what other
people had written.
Thank you Will.
--
Grant. . . .
unix || die
