Sorry to state the obvious, but it depends on the computer.
When I used to work on military computers they were rated down to -55C I think. The parts which were only connected in a lab were rated down to 0C/32F. My old Germanium transistor machine turns itself off below 10C/50F because thats what Mullard / GEC (the British one), the transistor manufacturers specified. Now they are getting on for 50 years old I don't power it up below 13C/55F. Normally we shut down the restoration project in November but today, with the aid of a couple of fan heaters, we were working on it. Increased levels of solar radiation has a few advantages, though its due to peak in 2012 I'm told. I imagine with valves, the potential problem would be the glass cracking. Cold is certainly more of a problem than overheating, generally if an operator can stand the heat so can the computer. I've heard tales of old ICT 1301s being operated by people stripped down to their pants (underpants for those to the left of the pond) when the air conditioning failed because otherwise the payroll run would not be done, and of course they themselves would not be paid as well as taking flak from all the other workers.
At work back in the 80s I had an Apple ][ euro-plus or maybe it was an Apple ///, anyway it was fitted with an external 'ICE' winchester drive. ICE being the brand. As we moved into winter it took longer and longer to start up in the morning depending on the temperature. We used to laugh at how appropriate the name was. Of course it eventually failed completely but at least we got a lot of warning and had a fairly full backup.
Roger Holmes
On 9 Dec 2009, at 06:56, cctalk-request at classiccmp.org wrote:
> Date: Tue, 8 Dec 2009 21:19:55 -0800
> From: "Zane H. Healy" <healyzh at aracnet.com>
> Subject: Running Computers Cold
> To: classiccmp at classiccmp.org
> Message-ID: <p06240836c744e3988e63(a)[192.168.1.199]>
> Content-Type: text/plain; charset="us-ascii" ; format="flowed"
>
> Okay, this is the first time I've ever had to worry about this. When
> is it to cold to run a computer? It's 35F out in the garage, and it
> is supposed to get a lot colder tonight. I just shut the
> dehumidifier down (to cold to run it) and setup a heater near the
> computers (and other stuff I don't want to freeze).
I find myself a little low on small capacity (250MB-1GB) SCSI-1 (not SCSI-2)
drives, which is sad, because I'm trying to restore one of my Alpha Micros
with one and the ones I have in stock are either spares for the Macs or
otherwise allocated. Does anyone have some lying around they don't need and
could make some arrangement to part with? If so, please contact me off list.
--
------------------------------------ personal: http://www.cameronkaiser.com/ --
Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com
-- Famous, adj.: Conspicuously miserable. -- Ambrose Bierce ------------------
On 12/9/09, Zane H. Healy <healyzh at aracnet.com> wrote:
> No denying that. Off the top of my head Ultrix-32 v2 is probably the
> minimum you'll get running on a MicroVAX II.
I loaded Ultrix T2.0 (pre-release "Test" version?) from TK50 in about
1986 or 1987 on an early MicroVAX II. Prior to that, I loaded some
flavor of Ultrix v1 from magtape onto an 11/730 w/RB80 disk. That
doesn't say what will or won't work in terms of the boundary cases,
but it's two points on the curve.
In both cases, I remember that installation took most of a day, and it
was a major wait for the kernel to compile.
-ethan
Does anyone have a spare amiga 500 512k trapdoor memory upgrade (or similar)
that you'd be willing to part with? I'm looking for the cover as well.
Thanks.
brian
Does anyone know where I can find documentation for this unit?
Google turns up mention of one being sold on eBay with a PDF of the
manual, but the listing is long gone from eBay. Wayback machine turns up
nothing.
Steve
--
> Date: Thu, 10 Dec 2009 18:09:08 +0100
> From: Philipp Hachtmann <hachti at hachti.de>
> Subject: RK05 alignment - without alignment pack?
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at classiccmp.org>
> Message-ID: <4B212B34.6070003 at hachti.de>
> Content-Type: text/plain; charset=ISO-8859-15; format=flowed
>
> Hi folks,
>
> I took a "new" RK05 disk drive from my heap. After defoaming I powered it
> up. I soon realized that
> the position sensor's glass had fallen off. Can be glued back in place
> easily. But after that I'll
> most probably have a misaligned RK05.
>
> The RK05 manual tells me how easy it is to realign the heads: Just load
> the alignment pack and...
> -- But I don't have an alignment pack :-(
>
> Does anybody (best would be in Europe) have an RK05 alignment pack I could
> use?
>
> Is there a known trick to do it without alignment pack? I have working
> drives and formatted disks handy.
>
>
> Best wishes,
>
> Philipp
> ------------------------------
With a good eyeball and a careful hand u can align to data. Since you have
what you hope are calibrated drives, I would try taking a formatted pack on
a good drive and writing 1F and 2F signals on alternate tracks, 2F on TK00,
1F on TK01, etc. (I don't know what the RK05 code is but 1F and 2F
translates to some repetitive pattern). It is not necessary to do so on the
whole pack, just circa TK00 and someplace in the middle of the pack.
The analog signal will have a broad flat peak region as u move the heads
across the track, so u can either eyeball the center of a track or better
yet use a micrometer gauge to measure the region and then move it to the
center. I'm not sure whether it is better to look at the entire track or
two sectors 180 degrees apart. Depending upon the resolution of the
recording system, the peak of a 2F should be about 0.7 of the 1F, so it
should be obvious as u move across a track.
Since you are liable to be several tracks off, the first thing you have to
do is find Track Zero, which should be where the 1F/2F repetition starts.
Once u get all the heads aligned at Track Zero, do it again at TK01 where
you should have a clear track center (1F surrounded by 2F). Then move to
the center and look at the signal again. You don't have to move the heads,
just apply pressure to the carriage and see if you are more or less
centered.
The acid test is then when u read the pack :-)
Tom
Given the recent iteration of the recurrent "how will we save our data in N
years" thread, where N is Sufficiently_Large, I discovered this interesting
tool.
http://ollydbg.de/Paperbak/
There is something terribly attractive about this. I'm tempted to play with
it to see how practical it is, after I've ported it to Mac OS X, of course.
--
------------------------------------ personal: http://www.cameronkaiser.com/ --
Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com
-- Wagner's music is better than it sounds. -- Mark Twain ---------------------
Hi folks,
as I already mentioned in alt.sys.pdp8 I'm currently experimenting with a TD8E controller in a
pdp8/e and more than one TU56.
I installed two TU56. The first one has the G888 modules. The second one will be daisy-chained to
the first one.
Currently I tried only the control cable. Forgot to bring the data cable with me. It looks as I now
can access units 0 and 1 on both TU56. I'm quite confident that the data part will work as well.
Currently only one or two of the four transport are working properly (The drives are currently being
repaired) but there's enough functionality for a proof of concept.
The next step will be three modifications:
1. Make the TD8E respond to all four TD8E addresses - This is done easily and non-destructive by
pulling the address select jumpers to ground.
2. Add a latch to the TD8E that will hold the two TD8E address bits and feed them through two former
ground lines of the cable.
3. Add a demuliplexer to the paddle board. Use the original select signal and the two additional
ones to generate 8 select lines.
If I'm right I'll have a TD8E that supports up to 8 tape transports (4 TU56). That would be very
nice for the beginning.
If anybody has already tried this or there's something I've missed, please let me know!
Regards,
Philipp :-)
--
http://www.hachti.de
Picked up an old terminal in very nice cosmetic condition; it works fine
barring a bit of visual "jitter" on the display -- not sure how best to
describe it. The picture is clear and sharp but occasionally a few
scanlines will spike off to the right a bit. Coinciding with this
spiking are tiny crackling noises from inside the monitor. (Or at least
it seems like they coincide, obviously I can't verify this.)
I thought it might be HV leakage based on discussions I've seen on this
list. I've run it with the cover off and the lights off and I can see
no evidence of sparking or other visible discharge.
Any thoughts?
I hate working on CRTs. I'm not great with electronics (getting slowly
better) but I can handle debugging low voltage stuff. Fixing monitors
scares the heck out of me...
- Josh
