
IBM, sonic delay lines, and the history of the 80×24 display - rbanffy
http://www.righto.com/2019/11/ibm-sonic-delay-lines-and-history-of.html?m=1
======
paulgerhardt
A few years ago I had the pleasure of working with Lee Felsenstein on an
electronics design.

One night over burrito bowls we got to talking about the Osborne 1 and the odd
size display. Specifically why _52_ x 24 instead of 40x24.

As the story goes, there were huge concerns the computer would come in under
budget. At the time chip companies would bundle their CPU’s and RAM - loss
leading with one but charging more than market for the other. Architectures
should have meant these chips were not cross compatible. Adam Osborne set a
hard ceiling on the price, Intel compatibility, and 40x24 native resolution
for the display (so as to be compatible with with other “Business”
applications). Facing these constraints Lee couldn’t make it work unless he
got creative. Through some arcane use of the dark arts (read: layout and
capacitor placement) he was able to get the timing working between the low
cost Z80 processor and the low cost 4116 RAM.

When he presented the news it went something along the lines of: “Adam, I’ve
got some good news for you and some bad news. The good news is I made the
cheaper ram work with the Z80 and we’re going to come in under budget. The bad
news is I can’t get you 40x24, but I can do you one better: 52x24!”

As I understand it, this has something to do with the timing weirdness when
integrating into the Z80s built in refresh logic which Motorola devs had to
write in software. My understanding is they rolled with it but Adam went on to
flush the savings windfall this hack got them down the drain by announcing the
Osborne 2 at a lower price with more features before the Osborne 1 shipped.

~~~
duskwuff
It wasn't uncommon at the time for small computer systems to make the memory
reads performed by video output pull double duty as a memory refresh. The
Apple II relied upon this, for example, and ended up with an oddly fragmented
video memory layout as a result.

------
mojuba
No matter how outdated and irrelevant those computers are today, their look is
so nostalgic to me like no other thing. Other things that disappeared from our
lives, such as rotary phones, vinyl records (not completely lost though), the
beautiful stereo systems of the 1980s, etc can never compare to the feeling of
seeing and touching a computer for the first time. The magic of technology is
lost at least for my generation, I don't know about the others.

~~~
K0SM0S
It depends. Technology became magic beyond our wildest dreams too, in many
respects, when we take a second back to look at first principles, how far
we've come. Part of that magic was age and personal disposition too, in
addition to the revolutionary object. That combination doesn't happen quite
often.

But imagine a true sci-fi-esque VR experience a decade or two from now in
company of your children or grand-children on a Christmas evening, that might
make you feel in magic-land all over again.

~~~
otabdeveloper4
Progress doesn't work like that. Once you've picked the obvious low-hanging
fruit it stops being a research problem and starts being an engineering one.
Which means tradeoffs and no free lunch and no more magic.

We're never gonna have an airliner that is 10 times faster than the ones we
have now. Same principles with computing too.

~~~
Miraste
I don't know, using a VR headset for the first time is the most magical tech
experience I've ever had and that was barely three years ago. Modern VR came
about because all the disparate pieces of tech involved slowly improved over
decades, until one day they all worked well enough to create something
humanity could only dream of just a few years ago. There are a lot of fields
in similar situations. We have room for some magic yet.

------
DrScump
"The punch card remained a keystone of data processing until the 1970s, and
its impact still remains."

I worked for an aerospace contractor in the mid-80s, and the corporate
computing center was an IBM mainframe shop (originally 360s/370s, later a mix
of 370s and 3033s, later the 308x multiprocessors series).

Even when I left that world in 1986, punch cards were still used in several
contexts, such as the starter decks for all production jobs. But the greatest
reliance on punch cards was that _every employee 's time card was a punch
card_. Recurring data was pre-punched, employees would write billing hours and
projects on printed fields, then that data was punched in by the keypunch
department at the end of the week. The timecards then were written to tape and
fed into accounting, payroll, and shop order control.

Yet despite this primitive appearance, every employee got their paycheck by
the following Thursday, every week.

------
Footkerchief
For background, the "sonic delay line" appears to refer to this:

[https://en.wikipedia.org/wiki/Delay_line_memory#Magnetostric...](https://en.wikipedia.org/wiki/Delay_line_memory#Magnetostrictive_delay_lines)

~~~
jiveturkey
> A later version of the delay line used metal wires as the storage medium.
> Transducers were built by applying the magnetostrictive effect; small pieces
> of a magnetostrictive material, typically nickel, were attached to either
> side of the end of the wire, inside an electromagnet. When bits from the
> computer entered the magnets the nickel would contract or expand (based on
> the polarity) and twist the end of the wire. The resulting torsional wave
> would then move down the wire just as the sound wave did down the mercury
> column. In most cases the entire wire was made of the same material.

wow. this is literally a sound wave. i thought it was some kind of euphemism.

as i was until now only familiar with the electric variety.

~~~
Koshkin
> _literally a sound wave_

Well, not literally. A sound wave is a compression wave (vs. shear or
torsion).

------
Taniwha
This is very much an IBM-centric narrative - it doesn't mean that it's wrong
but at the time there really was an IBM world and an everyone else world - IBM
carefully tended to its walled garden, to the point of getting people fired
who might consider looking outside of it - the result is people who knew
nothing about IBM, and people who knew nothing but.

Which essentially means that there are going to be different stories about
80x24/5 from that time - probably all of them correct in context.

(oh and the console monitors on our Burroughs 6700 mainframe had delay lines
while the user block terminals - TD830s - had dram and micro-controllers -
there's another non-IBM/non-DEC world view of essentially the same technology)

~~~
mattrp
Well yes to this - in the 80s you were either System V or whatever crap IBM
was selling back then! :)

Ps I always assumed 80x24 was a teletype (eg. tty) standard or at the least a
two-by 80x12 punch card layout. I also wonder if the serial cable throughput
to the terminal played a role..

~~~
tgv
I think RSX, RT-11 and VMS would like a word.

~~~
mattrp
Sorry I was being intentionally controversial. I had both Unix and vms
accounts as a student and I guess the vms never really resonated with me...

~~~
tgv
Don't worry. I never liked it either. When I found Unix, I was sold. I think
it was the pipe (in the shell) that did it.

~~~
mattrp
For the longest time I had my systems cat Syslog to an lpr... anytime someone
did something, I’d hear a bzzzzzt. Usually about 5 times a day. Maybe a dozen.
Then one morning I came into work and there was a whole box of paper on the
floor and the printer is still bzzt, bzzt, bzzt... it was a hacker who had
decided to follow some instructions he found on the web and hack my system.
Every time he’d do something he’d erase his steps... but he never checked to
see that all his movements were being printed!

------
chiph
> AT&T introduced the Teletype Model 40 in 1973, a CRT terminal with an 80×24
> display.

The Model 40 was a nice machine. I remember it because the printer unit reused
the type pawls from the Model 28 in a rubber belt that ran the full width of
the paper (80 columns, of course). So it was a chain printer without the
chain, which meant it was somewhat quiet when printing.

------
jes
I can still hear the sound that an ASR-33 would make as it was typing out a
listing. I was fortunate to attend a high school in 1975 or so that had a DEC
PDP-8 with an attached ASR-33 with paper tape reader and punch. I remember
that it took something like 45 minutes to load the BASIC interpreter from
paper tape. Good times.

~~~
rbanffy
I love the cadenced hum of the ASR-33 when it idles. Wish I could have one in
my office.

------
Sniffnoy
Non-mobile link: [http://www.righto.com/2019/11/ibm-sonic-delay-lines-and-
hist...](http://www.righto.com/2019/11/ibm-sonic-delay-lines-and-history-
of.html)

------
kps
The ‘recent blog post’ that Mr Shirriff mentions was discussed on HN at
[https://news.ycombinator.com/item?id=21340548](https://news.ycombinator.com/item?id=21340548)

------
wazoox
There is a mistake somewhere: the 3270 is said to have been introduced in
1977, but to dominate the market by 1974. Could it have been introduced in
1971 instead?

~~~
kens
You are right; I've fixed the typo.

------
projektfu
"The new 32- and 43-line sizes didn't really catch on"

But it made it to the PC and its MDA video, IIRC. I used to use that mode all
the time.

~~~
dragonwriter
I don't recall 32- or 43-line MDA text modes (and online sources on MDA I can
find don't list such modes), but EGA and later adapters supported 43-line text
modes, which I do remember using.

~~~
projektfu
IRI. :) definitely then I used the EGA mode. I had a Hercules compatible
adapter that supported EGA mono modes.

------
hazeii
From the article, about why 80x25 became standard:-

>The biggest problem with this theory is the VT100's display was 80×24, not
80×25

Having spent quite a few years banging away on VT100's and clones, wasn't the
display actually 80x25, but with the 25th line being used to show status? So
the electronics was actually set up for 25 lines.

~~~
kens
No. The VT100 was 80×24 (or 132×14 or 132×24) and had no status line. You can
verify this on Wikipedia or in the manual. The status line was added in the
VT320.

[http://www.bitsavers.org/pdf/dec/terminal/vt100/EK-
VT100-UG-...](http://www.bitsavers.org/pdf/dec/terminal/vt100/EK-
VT100-UG-001_VT100_User_Guide_Aug78.pdf)

------
cannam
Interesting article with some nice pictures and links.

I have a very simplistic question. The article asks, "Given the historical
popularity of 80x24 terminals, why do so many modern systems use 80x25
windows?" My question is: _Do_ any modern systems use 80x25 windows, other
than the console of the IBM-compatible PC?

~~~
kens
I believe 80x25 is the default for iTerm, qemu, as well as cmd/command on
Windows, minicom, kermit, and CentOS console. Anyone know of other current
users of 80x25?

~~~
int_19h
MATE Terminal defaults to 80x25 as well.

