The 2250 was very interesting to me. I took a class on 2250 programming
in 1968. I learned that it had both character and graphics mode. The
character mode was of special interest and I developed a full-screen
editor that let the group I was working in at the time develop and edit
source code and data files. It wasn't quite as good as ISPF's editor
(which wasn't around yet), but it was a lot better than TSO's line
editor. The screen was also much bigger than the 2260's and could
display a whole card image.
You could overtype data directly on the screen and there was a single
line on the screen (at the bottom) which permitted commands that
supported single line and block moves, copies and deletes.
It saved the group a great deal of effort in developing programs and
course material. I was teaching PSRs at IBM's Field Engineering school
in Poughkeepsie at the time.
Brings back some pleasant memories.
Mike Myers
Mentor Services Corporation
On 11/11/2011 09:11 AM, Chris Mason wrote:
To all who may be interested in the 2250
The Wikipedia article is quite short so here it is in its entirety.
<quote>
IBM 2250
The IBM 2250 Graphics Display Unit was announced as part of System/360 in 1964.
Unlike most modern computer displays, which show images in raster format, the
IBM 2250 used vector graphics. A display list of line segments (vectors) on a
1024 by 1024 grid was stored in the computer's memory and repainted on the
2250s CRT up to 40 time per second. Characters were built of line segments
specified by display list subroutines. Thus any character set or font could be
displayed, although fonts were generally extremely simplified for performance
reasons. The computer altered the display by changing the display list. As the
display list got longer, the refresh time got longer too and eventually the
display would start to flicker.
The 2250 was housed in a desk with an alphanumeric (QWERTY) keyboard and a separate
programmed function keyboard which had keys, indicator lights and switches. A
plastic overlay label could be placed over the function keyboard. Punches on the top
edge of the overlay could be sensed by the computer so the keys, lights and switches
could be reprogrammed simply by changing overlays. The 2250s CRT measured 21"
diagonal, but the useful display area was 12 inch by 12 inch. A light pen was
provided as a pointing device, serving the function of the modern computer mouse.
An IBM 2285 Display Copier could be attached to the 2250 to provide 8½ by 11
inch hard copy of the display contents under operator control.
</quote>
http://en.wikipedia.org/wiki/IBM_2250
... but I do not remember the size.
It covers the key point I wanted to make in connection with this comment. If "size" is a
reference to character rows and columns, we are comparing "apples and oranges" as I hope
can be noted from the description.
">" ... although fonts were generally extremely simplified for performance
reasons.
I saw one at one time in use as a console in the Santa Teresa labs - and possibly
elsewhere - my memory's not what it was! The "feature" of the presentation of
console messages which most impressed was actually the relative crudeness of the
character rendering.
Incidentally one could suppose that this type of display technology, rendering characters
from subroutines of a mathematical nature using lines with start and end coordinates,
would find approval from at least one denizen of this list who has gone on record
regarding his - for it is a "he" - disgust at the technology of display devices
which simply display characters of one font within character cells within the
presentation space relative to the beginning of a linear buffer.
Chris Mason
On Fri, 11 Nov 2011 05:08:28 -0800, Lloyd Fuller<[email protected]> wrote:
There was also a 2250 in that timeframe, but I do not remember the size. We had
one of each in Stuttgart, but could not use them because the request for the
extra memory to be able to run the communications program was cut from the
budget request. The general did not care about the system memory, just the
CRTs.
Lloyd
----- Original Message ----
From: Ed Gould<[email protected]>
To: [email protected]
Sent: Thu, November 10, 2011 8:55:41 PM
Subject: Re: TSO SCREENSIZE
Rick,
My memory is iffy here as well but I do remember that we had 12 x 80 screens but
the model number was 2260. The screen was incredibly small. This was in the
early 1970's.
Ed
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