tl;dr: A kit for targeting several old or old-ish platforms, with code in some languages popular in the 1980s: C89 (ANSI C), Pascal, Modula 2, Basic. A 'kit' here means: frontend, codegen, support libraries and some tools. This is apparently known as being the default toolchain for Minix 1 and 2.
But - the repository is not "everything you need"; it actually relies on a lot from an existing platform - GCC, Lua, Make, Python etc. So, you would typically use this to cross-compile it seems.
consp•Feb 14, 2026
> apparently known as being the default toolchain for Minix 1 and 2.
That is not very surprising since Tannenbaum is a professor there and cowrote wrote the ACK and wrote Minix.
tgv•Feb 14, 2026
It doesn't rely on gcc. Any C compiler will do. The rest is there to build it on " Linux, OSX, and Windows using MSYS2 and mingw32". Indeed for cross-compilation, as it won't run on CP/M.
phicoh•Feb 14, 2026
ACK used to be self-hosting. Of course, standard Unix utilities like sh and make are required. I still use one of those versions.
It's interesting that they have a Raspberry Pi GPU backend, but neither an ARM backend nor any modern ISA. (such as x86-64, Aarch64, etc.) Is there any example program that actually runs on the rpi gpu? I skimped the website, but it is only mentioned in the release notes.
barfiure•Feb 14, 2026
I’m still making my way through the MINIX book. Love it.
AlexeyBrin•Feb 14, 2026
Are you working through the 1st or 2nd edition of the book ? I think these are the ones that used ACK.
rwmj•Feb 14, 2026
I remember after I read the 1st edition, bought MINIX ($150 !!), and then was very annoyed to find that the compiler source was not included. Luckily it was '89 or '90 and GCC sources were available.
pjmlp•Feb 14, 2026
One of the first widely used compiler toolkits with multiple frontends, intermediate language for the phases and a common backend.
Contrary to common understanding LLVM wasn't the very first one, ACK also not, there are others predating it when diving into compiler literature.
ptx•Feb 14, 2026
Is this the same compiler that famously spurred Richard Stallman to create GCC [1] when its author "responded derisively, stating that the university was free but the compiler was not"?
It seems to be free now anyway, since 2005 according to the git history, under a 3-clause BSD license.
7 Comments
2025: https://news.ycombinator.com/item?id=42833638
2020: https://news.ycombinator.com/item?id=22310987 and https://news.ycombinator.com/item?id=22612420
But - the repository is not "everything you need"; it actually relies on a lot from an existing platform - GCC, Lua, Make, Python etc. So, you would typically use this to cross-compile it seems.
That is not very surprising since Tannenbaum is a professor there and cowrote wrote the ACK and wrote Minix.
Contrary to common understanding LLVM wasn't the very first one, ACK also not, there are others predating it when diving into compiler literature.
It seems to be free now anyway, since 2005 according to the git history, under a 3-clause BSD license.
[1] https://www.gnu.org/gnu/thegnuproject.en.html