Ken Shirriff's blog

Computer history, restoring vintage computers, IC reverse engineering, and whatever

Showing posts with label ibm1401. Show all posts

Showing posts with label ibm1401. Show all posts

Repairing a 1960s-era IBM keypunch: controlled by mechanical tabs and bars

In this article I describe repairing an IBM 029 keypunch that wouldn't punch numbers. Keypunches were a vital component of punch card co...

Creating a Christmas card on a vintage IBM 1401 mainframe

I recently came across a challenge to print a holiday greeting card on a vintage computer, so I decided to make a card on a 1960s IBM 140...

Identifying the "Early IBM Computer" in a Twitter photo: a 405 Accounting Machine

The photo below of a "woman wiring an early IBM computer" has appeared on Twitter a bunch of times , and it stoked my curiosity:...

One-hour Mandelbrot: Creating a fractal on the vintage Xerox Alto

I wrote a short program to generate the Mandelbrot set on the Xerox Alto, a groundbreaking minicomputer from the 1970s. The program, in...

1950's tax preparation: plugboard programming with an IBM 403 Accounting Machine

Long before computers existed, businesses used electromechanical accounting machines for data processing. These one-ton accounting machines ...

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