Microsoft's First Product: The Altair BASIC Source Code (1975)
Altair Basic Interpreter Source Code (1975) [pdf]
This PDF contains the original source code for Altair BASIC, Microsoft's first product, written by Bill Gates, Paul Allen, and Monte Davidoff in 1975. The 157-page document offers a rare look at the programming that launched the PC software industry, including handwritten annotations and the original comments.
Altair BASIC was the first product Microsoft ever made, and it marked the beginning of a revolution in personal computing.
- petilon
Credit should be given to Digital Equipment Corporation. Back then software isn't what companies made money on, it is hardware. Source code wasn't guarded as a secret as it is today, and you could find print outs in the dumpster [1]. Bill Gates and Paul Allen found the source code of DEC Basic [2] and ported it. (Wikipedia says Microsoft Basic was "inspired by" DEC's PDP-10 BASIC-PLUS.)
[1] https://www.businessinsider.com/10-things-you-didnt-know-abo...
[2] https://www.theregister.com/software/2000/06/29/bill-gates-r...
- davidfekke
Here is the 6502 assembly source code for Microsoft Basic:
- piker
These two guys* were crazy productive in the 2 months they worked. Just the level of commenting shows how much thought they were able to give it during that span.
* plus the math package guy
- thrownawaysz
"FILE WILL BE DELETED AFTER PRINTING"
hah I've never seen that before but reminds me to roguelike games.
"permadeath coding" would be actually fun. IF compiler error THEN erase code repository or something like this
- ChrisArchitect
Associated blog post from 2025:
Celebrate 50 years of Microsoft with the company's original Source code
https://www.gatesnotes.com/microsoft-original-source-code
(Discussion: https://news.ycombinator.com/item?id=43575884)