IBM 1620 Model 2 emulator brings 1960s computing to the browser
Web-based IBM 1620 emulator and IPL-V from 1963
A web-based emulator for the IBM 1620 Model 2, a 1960s decimal computer with no registers and a two-address architecture. The project also recovers software, including IPL-V from 1963. The 1620 used magnetic-core memory and digit-sequential arithmetic, and about 2,000 units were produced. The emulator aims to preserve this rare system for modern browsers.
The main goals of this project are creation of a web browser-based emulator for the Model 2 variant of the system and recovery of as much software for the system as we are able to find.
- fernly
I have heard that among older IBMers the 1620 (model 1) was known as CADET, for "Can't Add Doesn't Even Try".
- rzzzwilson
A blast from the past! An IBM 1620 was the very first computer I programmed, way back in 1969, likely a model 2. As part of a second year Applied Mathematics semester we were given a block of coding forms, a McCracken book on FORTRAN II and a list of problems to solve. There was no instruction on how to do this beyond reading the book, as far as I can remember. Someone punched cards from our coding forms and put them into the machine. We never actually got to touch the hardware, but we could look at it through glass windows.
That was a life-changing experience as it led to me dropping out of my Physics degree and eventually going into a computing career.
- kragen
Currently the title says "Web-based IBM 1620 emulator and IPL-V from 1963" until HN's title policy inevitably vandalizes it to remove the informative part. But, to give further context on IPL-V, IPL (I think actually IPL-IV) was key to some early AI research, but the main reason it's interesting in 02026 is that it's what inspired Lisp. It's a terrible programming language by today's standards, and the manual is a horrible slog, but you can see the seed of almost every programming language popular today in it.