Search Results for: shirriff

recursive alto

Comments Off on recursive alto

shirriff_recursive_alto2_450w

Ken Shirriff has been restoring a vintage Xerox Alto computer (the PC Steve Jobs "borrowed" his ideas from). Using the BCPL programming language, a precursor to C, he made this image of an Alto on an Alto on an Alto [etc]

Before Wikipedia such an image would have been called infinitely recursive and everyone would have known what you meant ("infinite" within the limits of screen resolution, of course). Now the Wikipedians are encouraging us to use the term Droste Effect, after an obscure cocoa package design. Thanks, I'll pass, but Redditnerds are all over it with an online festival of recursive computer screen images they're calling Droste Week. Here's a typical example (most of these aren't very infinite):

recursive_atari600w

Earlier posts on Shirriff and the Alto restoration.

Draw 4.5 (1979)

Comments Off on Draw 4.5 (1979)

Ken Shirriff has been restoring a vintage Xerox Alto computer (the PC Steve Jobs "borrowed" his ideas from). On Day 10 Shirriff got the Draw 4.5 program up and running. He can't draw with it yet because the mouse that came with the Alto isn't compatible (the donor bought a substitute off eBay, it turns out). But here's what the interface looks like (jpeg cropped into two parts to fit here):

draw4-5_1979_gui_shirriff_top_crop

Some of these functions are familiar and some are obscure but it's intriguing to see a 37 year old toolbar. Eventually, maybe, we'll have our Roland Barthes who can explain how present-day visual language was warped, I mean, shaped, by this configuration.

draw4-5_1979_gui_shirriff_bottom_crop

ibm mainframe computing bitcoin hash function (slowly)

Comments Off on ibm mainframe computing bitcoin hash function (slowly)

ibm_mainframe

This animated GIF comes from Ken Shirriff's blog. Shirriff used a vintage IBM mainframe computer to compute the cryptographic "hash" functions that are the basis of bitcoin mining:

The IBM 1401 can compute a double SHA-256 hash in 80 seconds. It requires about 3000 Watts of power, roughly the same as an oven or clothes dryer. A basic IBM 1401 system sold for $125,600, which is about a million dollars in 2015 dollars. On the other hand, today you can spend $50 and get a USB stick miner with a custom ASIC integrated circuit. This USB miner performs 3.6 billion hashes per second and uses about 4 watts.

Shirriff's also produced a Mandelbrot image on the mainframe. His photos of the hand-wired guts of the IBM 1401 are fascinating.