In 1979, I made a program called VisiBase in this BASIC.
It's a visual database modeled after VisiCalc.
That won me a joystick in at a competition by the local computer store. :-)
Still have the source, that works in an Apple 2 emulator. It's 13 K in ASCII (untokenized).
The Apple ][ basic interpreter placed its "get next token" routine down in the first 255 bytes of the computer's memory. Being there allowed for the machine instructions to be fetched twice as fast as "high memory". And "get next token" is definitely a good guess for hotpath.
Sadly nothing in Scott's blog post about how they obtained the source. Was it still in Microsoft's archives? Did they happen upon some tractor-feed print-outs they had to type in by hand?
It would also be interesting why it was open-sourced now. I assume if they had done the same last year, the resulting loss of revenue would not have destroyed the plucky little $3T upstart.
The source code Scott & co. released is word-for-word exactly the same as the pirated source code that's been floating around the Internet since at least 2009, and that pagetable.com wrote about in 2018:
This is what Microsoft slapped a license and an AI-slop README on. Sure, they can legally do that, they still own the copyright, but it's still pretty funny that they're essentially laundering pirated software.
The Zork I/II/III releases were even more blatant, with git commits adding license texts to existing pirate (or, if you prefer, archival) releases of the old source code:
It makes me wonder how many of Microsoft's other releases of old source code are laundered pirate releases, but I don't want to be too harsh. Microsoft's actions in these cases are considerably nicer than, say, what Warner Bros. did about pirated Mortal Kombat 2 source code (takedown), or Nintendo's continued legal hostility toward everyone everywhere. Maybe other companies could learn not to be so dog-in-the-manger about their precious Intellectual Property.
Except that wasn't possible. Languages like BASIC and Forth exist because they were the only kind of language implementable in 4K with no disk. Pascal in its smallest form (UCSD p-system) still needed disk overlays. The smallest C compilers were poly phase, needing storage for intermediate state.
I am really torn about this. Sure Microsoft is doing a lot of open source today (.NET core, VS Code and a bit of historic curiosities such as this one) but the "open letter to the hobbyists" still stands :) Release the Windows source code then we are talking.
In 1979, I made a program called VisiBase in this BASIC. It's a visual database modeled after VisiCalc. That won me a joystick in at a competition by the local computer store. :-) Still have the source, that works in an Apple 2 emulator. It's 13 K in ASCII (untokenized).
Please, put it in a public git somewhere!
Ben Eater's 6502 series [1] uses MSBASIC for programming along with WozMon as the terminal interface.
[1] https://www.youtube.com/playlist?list=PLowKtXNTBypFbtuVMUVXN...
Is that the same BASIC as this?
The Apple ][ basic interpreter placed its "get next token" routine down in the first 255 bytes of the computer's memory. Being there allowed for the machine instructions to be fetched twice as fast as "high memory". And "get next token" is definitely a good guess for hotpath.
C64 also has a token parsing routine in zeropage.
Sadly nothing in Scott's blog post about how they obtained the source. Was it still in Microsoft's archives? Did they happen upon some tractor-feed print-outs they had to type in by hand?
It would also be interesting why it was open-sourced now. I assume if they had done the same last year, the resulting loss of revenue would not have destroyed the plucky little $3T upstart.
The source code Scott & co. released is word-for-word exactly the same as the pirated source code that's been floating around the Internet since at least 2009, and that pagetable.com wrote about in 2018:
https://www.pagetable.com/?p=774
This is what Microsoft slapped a license and an AI-slop README on. Sure, they can legally do that, they still own the copyright, but it's still pretty funny that they're essentially laundering pirated software.
The Zork I/II/III releases were even more blatant, with git commits adding license texts to existing pirate (or, if you prefer, archival) releases of the old source code:
https://github.com/historicalsource/zork1
https://github.com/historicalsource/zork2
https://github.com/historicalsource/zork3
It makes me wonder how many of Microsoft's other releases of old source code are laundered pirate releases, but I don't want to be too harsh. Microsoft's actions in these cases are considerably nicer than, say, what Warner Bros. did about pirated Mortal Kombat 2 source code (takedown), or Nintendo's continued legal hostility toward everyone everywhere. Maybe other companies could learn not to be so dog-in-the-manger about their precious Intellectual Property.
I assume today typing in by hand is no longer needed, with text parsing from images being table stakes for LLMs.
Previous discussion:
Microsoft BASIC for 6502 Microprocessor – Version 1.1 - https://news.ycombinator.com/item?id=45118392 - Sept 2025 (198 comments)
Related ongoing thread:
Microsoft open-sources "the earliest DOS source code discovered to date" - https://news.ycombinator.com/item?id=48253386 - May 2026 (110 comments)
Maybe Apple can finally release MacBasic now that Microsoft can no longer stop licensing their Basic to the Apple II family.
I'll even send Bill Gates a dollar for that:
https://www.folklore.org/MacBasic.html
I doubt the .gitignore, README.md, and SECURITY.md files were created 49 years ago, as the GitHub repo indicates :D
Ahead of their time ;-D
Do you think computing history would have been much different if Microsoft made a 6502 Pascal interpreter instead?
Pascal is a lot broader language and won't fit in sub 16KB of ROM (even if you exclude monitor [call-151])
They didn't invent the language. BASIC was already a popular language for beginners on microcomputers at that time.
Except that wasn't possible. Languages like BASIC and Forth exist because they were the only kind of language implementable in 4K with no disk. Pascal in its smallest form (UCSD p-system) still needed disk overlays. The smallest C compilers were poly phase, needing storage for intermediate state.
I am really torn about this. Sure Microsoft is doing a lot of open source today (.NET core, VS Code and a bit of historic curiosities such as this one) but the "open letter to the hobbyists" still stands :) Release the Windows source code then we are talking.