About Ken Shirriff

I'm interested in computer history and reverse engineering old chips. I am currently restoring a Xerox Alto.

Some projects:
Wrote the Arduino IRremote library for infrared remotes.
Attempted Bitcoin mining on a 55 year old IBM 1401 punch card mainframe.
Got six symbols added to Unicode including the Bitcoin symbol (₿).
Wrote an article on the first microprocessors for IEEE Spectrum.
Gave a talk on reverse-engineering old integrated circuits at the Hackaday Superconference (YouTube).


Email me at firstname.lastname@gmail.com. You can follow me on Twitter at kenshirriff to get blog updates. The RSS feed is here.


Richard said...

Great job you do.
It is of immeasurable value.
Very important his articles because it shows the evolution of electronics step by step, what ideas were formulated to overcome the obstacles encountered at the time.
This work will have more value in the future.

Maj Brazilian Army Richard Miranda
Brasilia - DF - Brazil

Excelente trabalho que você faz.
É de um valor imensurável.
Muito importante os seus artigos pois mostra a evolução da eletrônica passo a passo, quais idéias foram formuladas para contornar os obstáculos encontrados na época.
Este trabalho terá mais valor no futuro.

Maj Exército Brasileiro Richard Miranda
Brasília - DF - Brasil

Rubén Iglesias said...

For people who like me feel a great passion for those we like, electronics, touring your site is a pleasure. Thank you very much for sharing your knowledge and experience. From Argentina, Rubén Oscar Iglesias.

dave said...

Great read ! Enjoyed reading your steps and though process very much.

I once reverse engineered an HF Transmitter Control System made with a dual chip 4040? and core store and replaced it with a BBC microcomputer using a 6502 ! Great fun ! .. your working at a much lower level .. which I had always wondered about .. again .. great read .. Thank you !
Dave Parsons
Prior life BBC Engineer

Anonymous said...

Just wanted to say thank you for your awesome blog! I’ve recently rekindled my interest in electronics after about 20 years of focusing on other things and already having a lot of the basics down I really wanted to learn and explore things at a deeper level. I stumbled across your 7805 article first and it was exactly at the level I was challenged by and engaged with. Thanks for taking the time to share with the world! Can’t wait to read the rest of your entries!

Anonymous said...

hey, i learn a lot with you work.
thanks so much for share your knowing with all of us.
still working and i love you blog.

Anonymous said...

This is fantastic work. Truly inspirational. Thank you for sharing

Anonymous said...

This is fantastic work. Truly inspirational. Thank you for sharing

Anonymous said...

I like the cut of your jib Ken.

Ray said...

Ken, I am sure I have written you on this before.
"The D200 was followed shortly by another avionics computer that contained three CPUs and used in total 28 chips: the Central Air Data Computer, built by Garrett AiResearch (now part of Honeywell). The computer, a flight-control system designed for the F-14 fighter, used the MP944 MOS-LSI chipset, which Garrett AiResearch developed between 1968 and 1970. The 20-bit computer processed information from sensors and generated outputs for instrumentation and aircraft control"

For the F14 microprocessor you include the ROMs containing the programs but for the 4004 you don't. Don't you think the 4004 needs programmed. Both computer contain six chip types but you emphasize 26 chips for the F14 microprocessor and feature the 4004 as a single chip something. The uninformed is forced to believe you but I think you know better. Building a "mil-spec" 20-bit computer two years before the "commercial-spec" 4004 is a feat many have had a hard time to grasp. BOTH were made from the exact technology.

Around 1974 I programmed the first microprocessor pin ball game, Lucky Dice for Ramtek. I used a 4004 and the final design used way over 20 program ROMS.

I like your style and research details but PLEASE present accurate details so the uninformed are not fooled. I know you know the difference.

Ray Holt
F14 Microprocessor designer