Identifying Machine for DEC Memory

Rob Jarratt robert.jarratt at
Sat Apr 4 08:04:48 CDT 2020

Back to the original topic, someone suggested the memory would fit a DECstation 2100. They were right! I have done a short post about it Thanks for the suggestion :-)



On Fri, Apr 3, 2020 at 5:04 PM +0100, "Warner Losh via cctalk" <cctalk at> wrote:

On Fri, Apr 3, 2020 at 5:04 AM Liam Proven via cctalk 

> On Thu, 2 Apr 2020 at 18:00, Warner Losh  wrote:
> >
> > Thanks! Nice talk! I wish I'd stuck around but I was kinda fried after
> my talk...
> I understand. I was the same, and went to the café for a couple of beers.
> :-)
> > Surprised you didn't mention that we had 80 column xterms due to 24x80
> 25x80 terminals from the 70s and 80s. But this mirrored the 25x80 column
> 3270s from the 60s which mirrored cards which were 80 columns which owe
> their existence to Hollerith adapting the Jacquard looms from the 19th
> century which automated the looms of the 18th century... :)
> I did know about that story (this one:
> ) but there seems to be
> a lot of controversy around it...

Yea, it isn't as straight a line as I paint it...


This explanation ignores that terminals like the VT52 pre-date the PC world
and were made for some custom gear that DEC engineers made that had no
relationship to NTSC. VT-52 was 1974 and had 80x24 lines. The Apple ][ was
also designed for the TV, but wasn't 24x80 because most TVs at the time
couldn't cope, but even it had custom CRTs and even on those custom CRTs
there was no 80 column mode standard. But the VT-52 was just a reflection
of the VT-50 which was 80x12 lines which was a reflection of the
Datapoint-2200 which was introduced in 1970 which was 80x12 lines as well.
DEC copied this, I've been told in classes in school ("the early terminals"
is all I recall now), but I have no good references between the dots here.

So the connection between 029 punch cards and terminals is clear... But
beyond that back to hollerith and the census to the 029 punch cards is less
> And I always find I need to cut a lot of material to fit the time
> slot, in any case.

Ah, that's true... And the whole 80 column thing is pervasive today as a
standard for any reason...


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