3 ms·

Is this written in assembly? I thought Unix was written in C and you had to only write a C compiler to port it to other platforms. I remember that was the story

Is this written in assembly? I thought Unix was written in C and you had to only write a C compiler to port it to other platforms. I remember that was the story I was told.

beefhash 7y ago
UNIX was written in assembly at first. By the Fourth Edition, the kernel was rewritten to be in a version of C (that won't go through a modern C compiler anymore), both 1973. The C compiler itself was introduced in the Third Edition. Parts of userland would still be in assembly even until the 7th Edition (1979), such as roff(1) (nroff/troff were in C), parts of as(1) or chess(6).
pjmlp 7y ago
Not at all, UNIX had a couple of releases in Assembly before the C rewrite came to be. Likewise there were other high level systems programming languages being used since 1961. The lost notable one being ESPOL, replaced a couple of years later by NEWP, both Algol derivatives for systems programming. The OS was called Burroughs B5000, used compiler intrisics with zero Assembly and is still being sold nowadays by Unisys, as ClearPath MCP. There are other notable examples available to discover there was a decade old of other OSes and systems languages.