> -Original Message-
> From: cctalk On Behalf Of Van Snyder via
> cctalk
> Sent: 22 June 2021 00:00
> To: cctalk@classiccmp.org
> Subject: Re: IBM 1620; was: Early Programming Books
>
> On Mon, 2021-06-21 at 17:26 -0400, William Donzelli via cctalk wrote:
> &
On Mon, 2021-06-21 at 18:55 -0500, Gavin Scott via cctalk wrote:
> Oh yeah, that was like 12 years ago? I believe they had gotten the
> 1620 CADET (“Can't Add, Doesn't Even Try”) running
One of my colleagues, about fifty years ago, wanted to use the 1620 for
telemetry processing. So he replaced th
On Mon, Jun 21, 2021 at 1:43 PM Chuck Guzis via cctalk
wrote:
> For some (jprobably hallucinatory) reason, I thought there was a project
> at CHM to replace the 1620 core stack with semiconductor memory. Guess
> that never happened.
Oh yeah, that was like 12 years ago? I believe they had gotten
On 6/21/2021 4:00 PM, Van Snyder via cctalk wrote:
I was once told that the most valuable guy in a Honeywell 6080 Multics
shop was the plumber.
No water cooling.
On Mon, 2021-06-21 at 17:26 -0400, William Donzelli via cctalk wrote:
> > Of course, nowadays, the old R22 systems are being refilled with
> > purified propane, called R290. Cheap, with better thermal properties
> > than R22, but probably not legal when LCM picked up the 6500.
>
> When cleaning o
> Date: Mon, 21 Jun 2021 16:02:20 -0400
> From: Paul Koning via cctalk
>> On Jun 21, 2021, at 3:52 PM, Chuck Guzis wrote:
>> On 6/21/21 11:53 AM, Paul Koning wrote:
>>> Perhaps you were thinking about the CDC 6500 at the late lamented LCM?
>>> That got some replacement stacks, which was an int
> When cleaning out a 3rd party CDC dealer quite a few years back, he
> remarked that the CDC machines going way back all the way to the 800s
> were fantastically unpicky about how they were cooled.
So I just reread what I wrote, and see it is crap. What I meant is
that CDC machines going back all
> Of course, nowadays, the old R22 systems are being refilled with
> purified propane, called R290. Cheap, with better thermal properties
> than R22, but probably not legal when LCM picked up the 6500.
When cleaning out a 3rd party CDC dealer quite a few years back, he
remarked that the CDC machi
On 6/21/21 1:02 PM, Paul Koning wrote:
> Some vague memory says Purdue. LCM actually got it running, which was an
> interesting problem. It required recreating the inter-chassis cables (since
> the original ones were cut as part of dismantling the machine) and restoring
> the cooling system.
> On Jun 21, 2021, at 3:52 PM, Chuck Guzis wrote:
>
> On 6/21/21 11:53 AM, Paul Koning wrote:
>
>> Perhaps you were thinking about the CDC 6500 at the late lamented LCM? That
>> got some replacement stacks, which was an interesting puzzle because the
>> read data connection out of the memo
On 6/21/21 11:53 AM, Paul Koning wrote:
> Perhaps you were thinking about the CDC 6500 at the late lamented LCM? That
> got some replacement stacks, which was an interesting puzzle because the read
> data connection out of the memory modules is a differential analog signal
> carrying the sense
> On Jun 21, 2021, at 2:43 PM, Chuck Guzis via cctalk
> wrote:
>
> On 6/21/21 10:55 AM, Paul Koning via cctalk wrote:
>>
> memory. Nobody explained why that was a real problem.
>>
>> Core memory is fairly sensitive to temperature. In the case of the 1620,
>> there is a heating system that
> -Original Message-
> From: cctalk On Behalf Of Chuck Guzis via
> cctalk
> Sent: 21 June 2021 19:43
> To: Paul Koning via cctalk
> Subject: Re: IBM 1620; was: Early Programming Books
>
> On 6/21/21 10:55 AM, Paul Koning via cctalk wrote:
> >
> memory
On 6/21/21 10:55 AM, Paul Koning via cctalk wrote:
>
memory. Nobody explained why that was a real problem.
>
> Core memory is fairly sensitive to temperature. In the case of the 1620,
> there is a heating system that brings the core memory box up to its operating
> temperature, which is why it
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