Mandelbrot on a vintage IBM1401

Gepostet vor 8 Monaten, 8 Tagen in Misc Tech Share: Twitter Facebook Mail

mand1

Ken Shirriff hat im Computer History Museum in San Francisco einen ollen, aber funktionierenden IBM1401-Rechner gefunden. Also hat er dafür ein Mandelbrot-Apfelmännchen in Assembler programmiert, das Programm auf ebenso olle Lochkarten gestanzt, das Teil einmal durchrattern lassen – „The cards fly through the reader at the remarkable speed of 800 cards per minute so the Mandelbrot program loads in just over a second“ – und das ganze schließlich auf ’nem Zeilendrucker ausgegeben. Nice! (via Visualizing Math)

mand2

The program fits onto just 16 cards, but the card format is a bit unusual. The machine code for the Mandelbrot program is punched into the left half of the each card, with code such as M384417A395417. An interesting thing about the 1401 is the machine code is almost human-readable. M384417 means Move field from address 384 to address 417. A395417 means Add the number at address 395 to the number at address 417. The text on these cards is the actual machine code that gets executed, not the assembly code. Since the machine is character-based, not binary, there's no difference between the characters "428" and the address 428.

If you look at the right half of the cards, there's something totally different going on, with text like L033540,515522,5259534. There's no operating system, so, incredibly, each card has code to copy its contents into the right place in memory (L instruction), add the word marks (, instruction), and load the next card. In other words, the right hand side of each card is a program that runs card-by-card to load into memory the program on the left hand side of the card deck, which is executed after the last card is loaded.

To run the program, first you hit the "Power On" button on the IBM 1401 console. Relays clunk for a moment to power up the system and then the computer is ready to go (unlike modern computers that take so long to boot). You put the cards into the card reader and hit the "Load" button. The cards fly through the reader at the remarkable speed of 800 cards per minute so the Mandelbrot program loads in just over a second. The console starts flickering as the program runs, and every few seconds the line printer hammers out another line of the fractal. After 12 minutes of execution, the fractal is done.

mand3

Tags: Coding Fractals Hardware Mathematics Retrotech

cyber0

DIY-Cyberdeck64

Ein selbstgebasteltes Cyberdeck aus WilliamGibsonLand in einem C64c-Case von Herrn D10d3. Vergangenes Jahr hatte er erst ein Ono Sendai Cyberspace…

cszrpadwiaa7rc6

Samsung Galaxys Akku-Problem eskaliert

„That escalated quickly.“ (via Martin)

Binary Bandit steals 0s and 1s

Binary Bandit steals 0s and 1s

01010100 01101000 01100101 01101110 00100000 01110100 01101000 01101001 01110011 00100000 01101000 01100001 01110000 01110000 01100101 01101110 01100101 01100100 00111010 (via…

pet

C64-ASCII-GIFs

Tolle GIFs von Richard Winters. Viel A E S T H E T I C S und so, aber noch…

type

Audio from Typo-Outlines

Gestern auf der Konferenz der Association Typographique Internationale in der Academy of Fine Arts in Warsaw: Type-Designer Just van Rossum…

Bank Datacenter downed by Noise

Bank Datacenter downed by Noise

In Rumänien sind die Festplatten im Data-Center einer Bank gecrasht, weil der Krach während einer Feuerübung, bei der sie Gas…

c641

C64 Logo-Generator

C64 Logo generator, Code auf Github. (via Boing Boing) Using fonts ripped from lots of Commodore 64 demos of old,…

cube

Re:Cube-Composer

Über David Peters Cube-Composer hatte ich schonmal vor einem Jahr gebloggt, seitdem hat er das Teil bisschen aufgehübscht, den Code…

robots

Website inside robots.txt

Netter Hack von Alec Bertram, eine Website in robots.txt: What's going on here: When parsing robots.txt files, search engines ignore…

CrcSeNWWEAEmOhs

Fibonacci Everything

Exhibit 1: Exhibit 2: „i made a golden ratio bot. because why not.“ Exhibit 3: Fibonacci Flim-Flam

CqyJexUWAAEeWNY

Excellent Dwarf Fortress-Bug

Some Bugs are better than others. Aus einem Interview mit Dwarf Fortress-Macher Tarn Adams. (via @neoascetic) It’s funny how I…