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12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

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Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#11

Post by wglb »

Very nicely done article.

However, I think the 029 keypunch didn't overlap the lifetime of the 1401, but I could be wrong.

The other marvel of the day was the 1403 printer, which had a lifetime that went long beyond the 1401. It was a bit noisy, and the cover you see in the photos there did serve as a pretty good damper.

However, when I did a co-op at IBM in Portland Oregon during my engineering studies, they had a 1403 printer hooked to a 360/30 printing library catalog cards. There was a roll of card stock feed by an automatic feeder that set perhaps 5 feet from the printer. It would feed more stock from the three-foot diameter roll when the printer pulled the paper out. The length of card stock between the printer and the feeder served as a very effective sound amplifying board causing quite a racket.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#12

Post by jacquesm »

guru_meditation wrote: post #5
fractallyte wrote: post #2

Way back in 1985, a seminal 'Computer Recreations' column in Scientific American featured the Mandelbrot set: https://www.scientificamerican.com/media/inline/blog/File/De... (A K Dewdney's columns were always fantastic - a whole new world of wonder for early 'home computer' users!) After careful study, my brother coded it in assembly on a C64. We both had the idea to double the display resolution (from 320x200 to 640…

I loved AK Dewdney's columns. The Core War [1] columns influenced me profoundly. Would love to see the mandelbrot printout scans :) [1] http://www.koth.org/info/akdewdney/

If you liked his columns check out 'The Planiverse'.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#13

Post by woofyman »

GnarfGnarf wrote: post #9

I worked as a paid programmer on card systems in 1970. I'm not saying things were better then. Give me C++ and Python any day over Assembler. However, there was something magical about being able to step through your program one instruction at a time using a switch on the control panel, or being able to display and modify the memory with lights & toggle switches. It was like you were reaching right into the soul of t…

It was an awesome feeling when my card deck compiled and produced the correct output the very first time !

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#14

Post by keithpeter »

dekhn wrote: post #6
fractallyte wrote: post #2

Way back in 1985, a seminal 'Computer Recreations' column in Scientific American featured the Mandelbrot set: https://www.scientificamerican.com/media/inline/blog/File/De... (A K Dewdney's columns were always fantastic - a whole new world of wonder for early 'home computer' users!) After careful study, my brother coded it in assembly on a C64. We both had the idea to double the display resolution (from 320x200 to 640…

I learned about the set in '87 or '88 and wrote a BASIC program to calculate it on my Apple IIe using the "obvious" algorithm. I left my computer on overnight (I had no idea if it would overheat). However, even after a day, it hadn't even got to the interesting parts of the set- it was still off in the big bands of constant color around the set. When I got to college I had a PC (a 286 with no floating point hardware)…

Yup: 36 hours on a BBC B+ micro for monochrome mandelbrot. I used to leave it running over the weekend, and tried zooming into various parts of the set over some weeks. I used to photograph the monitor, and I'm now searching for the negatives...

"(Up until 1971, British currency was expressed in pounds, shillings, and pence, with 12 pence in a shilling and 20 shillings in a pound. This makes even addition complicated, as tourists often discovered.)"

Just after I had learned to add and subtract pounds shillings and pence, they went decimal! Ha!

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#15

Post by kens »

wglb wrote: post #11

Very nicely done article. However, I think the 029 keypunch didn't overlap the lifetime of the 1401, but I could be wrong. The other marvel of the day was the 1403 printer, which had a lifetime that went long beyond the 1401. It was a bit noisy, and the cover you see in the photos there did serve as a pretty good damper. However, when I did a co-op at IBM in Portland Oregon during my engineering studies, they had a 1…

Obviously the 029 keypunch overlaps the lifetime of the 1401 since they are both still working :-)

But seriously, the 029 was introduced in 1964 along with the IBM 360 mainframe, while the 1401 wasn't withdrawn until 1971, and some were used long after that, so they had plenty of overlap.

You're right that the 1403 printer is pretty cool. One interesting thing is it has a hydraulic pump running the paper feed, so it can skip lines very rapidly.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#16

Post by mikeash »

fractallyte wrote: post #2

Way back in 1985, a seminal 'Computer Recreations' column in Scientific American featured the Mandelbrot set: https://www.scientificamerican.com/media/inline/blog/File/De... (A K Dewdney's columns were always fantastic - a whole new world of wonder for early 'home computer' users!) After careful study, my brother coded it in assembly on a C64. We both had the idea to double the display resolution (from 320x200 to 640…

Pix or it didn't happen.

Sorry, what I mean to say is: if you happen to have those printouts somewhere convenient, I would love to see what a 1980s assembly language generated, dot matrix printed Mandelbrot set looks like.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#17

Post by wglb »

kens wrote: post #15
wglb wrote: post #11

Very nicely done article. However, I think the 029 keypunch didn't overlap the lifetime of the 1401, but I could be wrong. The other marvel of the day was the 1403 printer, which had a lifetime that went long beyond the 1401. It was a bit noisy, and the cover you see in the photos there did serve as a pretty good damper. However, when I did a co-op at IBM in Portland Oregon during my engineering studies, they had a 1…

Obviously the 029 keypunch overlaps the lifetime of the 1401 since they are both still working :-) But seriously, the 029 was introduced in 1964 along with the IBM 360 mainframe, while the 1401 wasn't withdrawn until 1971, and some were used long after that, so they had plenty of overlap. You're right that the 1403 printer is pretty cool. One interesting thing is it has a hydraulic pump running the paper feed, so it…

Thanks for the clarification.

The 1403 was quite an engineering marvel. Lower case, Upper case, many odd characters.

There is in fact a book published that was masterd by 1403 by David Grau, I believe.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#18

Post by joelberman »

wglb wrote: post #11

Very nicely done article. However, I think the 029 keypunch didn't overlap the lifetime of the 1401, but I could be wrong. The other marvel of the day was the 1403 printer, which had a lifetime that went long beyond the 1401. It was a bit noisy, and the cover you see in the photos there did serve as a pretty good damper. However, when I did a co-op at IBM in Portland Oregon during my engineering studies, they had a 1…

I entered the Navy in 1967 and went to IBM 029 school in San Jose sometime in 1968. And I also took a 1401 SPS/Autocoder course at UC Davis that year. A few years later I learned BAL on a 360 and they still had 026 keypunch machines. I assume they were leased machines, so the lease price came down fast towards EOL. Then they got spray painted and leased in Africa and So. America.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#19

Post by ams6110 »

krylon wrote: post #4

This is fascinating. While I have a soft spot for old computers, I don't think I would put that much time into such a project. I do admire the author's determination, though! I imagine it must have been a lot of fun and thoroughly enjoyed reading about it. Just the other day, I was talking to one of our automation engineers on the phone, and while waiting for his computer to reboot, we talked about old hardware. He t…

Paper tape was also oily, so it lubricated the punch as it moved through it. It had a certain tendency to spontaneous combustion.

Re: 12-minute Mandelbrot: fractals on a 50 year old IBM 1401 mainframe

#20

Post by DonGateley »

kens wrote: post #15
wglb wrote: post #11

Very nicely done article. However, I think the 029 keypunch didn't overlap the lifetime of the 1401, but I could be wrong. The other marvel of the day was the 1403 printer, which had a lifetime that went long beyond the 1401. It was a bit noisy, and the cover you see in the photos there did serve as a pretty good damper. However, when I did a co-op at IBM in Portland Oregon during my engineering studies, they had a 1…

Obviously the 029 keypunch overlaps the lifetime of the 1401 since they are both still working :-) But seriously, the 029 was introduced in 1964 along with the IBM 360 mainframe, while the 1401 wasn't withdrawn until 1971, and some were used long after that, so they had plenty of overlap. You're right that the 1403 printer is pretty cool. One interesting thing is it has a hydraulic pump running the paper feed, so it…

And the disk drives on that 360 had hydraulic actuators to move the heads. Was that the 2301 or 2311 disk, or something else? Where I was in IBM Poughkeepsie we kept our programs on removable disks of somewhere around 16 in. in diameter. I don't remember the capacity but it was in MB. At the end of the line of disk drives sat our 029 card punch. I spent way too many hours at that punch because my fingers were so inept. There was no backspace 'cause you can't unpunch holes.

We used a card based program to modify the code that accumulated on our personal disk as ISAM data sets. I set that up for my department after dropping and bursting open a very long portable card carrier (of mostly unsequenced cards) that was used before my 1967 "innovation." :-)

What shocks me at the moment is the incredibly clear 50 year old mental map and images I have of that machine room and the computers in it. A 360 model 50 that I primarily used. Beside that a model 40, down the isle a model 67, behind that a 7094 and further on a big ol' model 85. Across the hall a honking model 91. No 1401's in that room, however, but lots of 1403 printers.

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