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posted by LaminatorX on Thursday March 26 2015, @09:14PM   Printer-friendly
from the plots-of-plots-of-plots dept.

Here is a story for the computer history buffs. El Reg is reporting that Ken Shirriff, a programmer better known for work on Arduino, got access to a 50-year-old IBM 1401 mainframe in the collection of the Computer History Museum and programmed it to produce a Mandelbrot fractal, printing it out on a line printer. Even though the computer has a Fortran compiler, he wrote the program in assembly language.

While this is not exactly an amazing feat of software engineering in anyone's book, it is an object lesson in how difficult (and how fun) it was to program the ancient mainframes of our fathers' and grandfathers' times.

Mr. Shirriff's story and lots of pictures can be found on his blog.

Related Stories

Teardown of an ATX PC Power Supply 65 comments

Ken Shirriff has carefully disassembled an ATX PC power supply and blogged about his findings.

Have you ever wondered what's inside your computer's power supply? The task of a PC power supply is to convert the power from the wall (120 or 240 volts AC) into stable power at the DC voltages that the computer requires. The power supply must be compact and low-cost while transforming the power efficiently and safely. To achieve these goals, power supplies use a variety of techniques and are more complex inside than you might expect. In this blog post, I tear down a PC power supply and explain how it works.1

The power supply I examined, like most modern power supplies uses a design known as a "switching power supply." Switching power supplies are now very cheap, but this wasn't always the case. In the 1950s, switching power supplies were complex and expensive, used in aerospace and satellite applications that needed small, lightweight power supplies. By the early 1970s, though, new high-voltage transistors and other technology improvements made switching power supplies much cheaper and they became widely used in computers. Now, you can buy a phone charger for a few dollars that contains a switching power supply.

He goes through the input filtering, rectification, isolation boundary, splitting of DC, and other aspects including the standby mode circuits. He has written before about various power supplies and chargers before, including a historical overview in IEEE Spectrum.

Previously:
Ken Shirriff Unfolds A Nuclear Missile Guidance Computer With Impressive Memory
How "Special Register Groups" Invaded Computer Dictionaries for Decades
Mature Mainframe Prints Mandlebrot Fractal in 12 Minutes.


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  • (Score: 2) by TLA on Thursday March 26 2015, @09:43PM

    by TLA (5128) on Thursday March 26 2015, @09:43PM (#162975) Journal

    I know Ken S. from his work with the Stone Soup Group.

    (I don't have any Arduino gear)

    --
    Excuse me, I think I need to reboot my horse. - NCommander
    • (Score: 2) by Jeremiah Cornelius on Thursday March 26 2015, @10:41PM

      by Jeremiah Cornelius (2785) on Thursday March 26 2015, @10:41PM (#162997) Journal

      Fractint.

      Funny. Because Benoit Mandelbrot worked for IBM in the '60's, and produced his first plots of fractal sets on similar equipment of the era. The famous eponymous Mandelbrot fractal was printed a decade later, close to 1980, on not much-advanced IBM line-printer technology.

      --
      You're betting on the pantomime horse...
      • (Score: 0) by Anonymous Coward on Friday March 27 2015, @12:50AM

        by Anonymous Coward on Friday March 27 2015, @12:50AM (#163042)

        I used to dive into those fractals while dropping out on lsd in high school. Good times... Thanks for the memories

  • (Score: 2, Insightful) by Anonymous Coward on Thursday March 26 2015, @10:03PM

    by Anonymous Coward on Thursday March 26 2015, @10:03PM (#162982)

    From all of us who have spent a lot of time back in the day doing data analysis and printing plots, histograms, stem-and-leaf plots, etc., on line printers, just like that, let me just say, "get the fuck off of my lawn!"

  • (Score: 4, Funny) by Megahard on Thursday March 26 2015, @10:04PM

    by Megahard (4782) on Thursday March 26 2015, @10:04PM (#162983)

    What the immature mainframe printed out.

    • (Score: 1, Redundant) by LoRdTAW on Thursday March 26 2015, @10:11PM

      by LoRdTAW (3755) on Thursday March 26 2015, @10:11PM (#162987) Journal

      What the immature mainframe printed out.

      Penises of course.

      • (Score: 2, Funny) by hemocyanin on Thursday March 26 2015, @10:28PM

        by hemocyanin (186) on Thursday March 26 2015, @10:28PM (#162992) Journal

        Don't be coarse.

        It was boobies.

      • (Score: 5, Informative) by kaszz on Friday March 27 2015, @12:16AM

        by kaszz (4211) on Friday March 27 2015, @12:16AM (#163030) Journal

        ASCII Pr0n .. ;)

        http://www.asciipr0n.com/pr0n/pinups/pinup36.txt [asciipr0n.com]

        • (Score: 3, Informative) by TGV on Friday March 27 2015, @06:41AM

          by TGV (2838) on Friday March 27 2015, @06:41AM (#163118)

          In case all ya kids think that is a joke: it isn't. When I was small, I visited the computer center of the bank where my father worked. They had a brand new IBM 370 and for a few kids, they printed out Snoopy pictures like these: http://www.asciiworld.com/-Snoopy,512-.html. [asciiworld.com] I put one on the wall of my bedroom. Later, I discovered there were all kinds of EBCDIC art files. So the above link is indeed what the immature mainframe would print.

          • (Score: 2) by mendax on Friday March 27 2015, @06:44AM

            by mendax (2840) on Friday March 27 2015, @06:44AM (#163120)

            I've seen similar things. As a kid, it was quite a badge of honor to have one of those. They used to print those things out at the university I eventually ended up going to during their open house when I was a kid. However, they sold them and my dad was too cheap to buy one for me. Just another resentment against my parents to overcome.

            --
            It's really quite a simple choice: Life, Death, or Los Angeles.
          • (Score: 2) by hemocyanin on Saturday March 28 2015, @12:54AM

            by hemocyanin (186) on Saturday March 28 2015, @12:54AM (#163373) Journal

            fyi - link is broken

          • (Score: 2) by TGV on Saturday March 28 2015, @07:34AM

            by TGV (2838) on Saturday March 28 2015, @07:34AM (#163469)

            That's because the period at the end of the phrase is being added to the URL. That hasn't happened to me on a forum since 1999, I think. Well, here it is again: http://www.asciiworld.com/-Snoopy,512-.html [asciiworld.com]

  • (Score: 0) by Anonymous Coward on Friday March 27 2015, @07:34AM

    by Anonymous Coward on Friday March 27 2015, @07:34AM (#163126)

    I bet it will calculate the pi in 2 minutes...

    • (Score: 1, Insightful) by Anonymous Coward on Friday March 27 2015, @06:08PM

      by Anonymous Coward on Friday March 27 2015, @06:08PM (#163260)

      To how many significant figures?

      • (Score: 0) by Anonymous Coward on Friday March 27 2015, @09:47PM

        by Anonymous Coward on Friday March 27 2015, @09:47PM (#163342)

        I concur, infinite digits per second is a pretty impressive output rate for an old mainframe.

    • (Score: 2) by maxwell demon on Saturday March 28 2015, @08:36AM

      by maxwell demon (1608) on Saturday March 28 2015, @08:36AM (#163478) Journal

      The Raspberry Pi, or the Banana Pi?

      --
      The Tao of math: The numbers you can count are not the real numbers.
  • (Score: 2) by bradley13 on Friday March 27 2015, @09:02AM

    by bradley13 (3053) on Friday March 27 2015, @09:02AM (#163134) Homepage Journal

    Been there, done that and lots of similar projects, when the mainframes (an IBM 360 in high school, a CDC Cyber 72 in college) were current technology.

    Sometimes it really strikes you just how fast technology has progressed...

    --
    Everyone is somebody else's weirdo.