Interesting trivia about the connection to plan9 the operating system.

>Go uses its own internal assembly language called Plan9.

Plan9 is the name of the OS. You wouldn't name a programming language "Linux", even if Linus created it and it was super related or not at all related.

It's not "plan9 assembly language" as in "the assembly language named plan9". Read it as "the otherwise unnamed custom assembly language used in the plan9 operating system".

The article simply misspoke by saying that the assembly language is "called plan9".

No way, the article consistently refers to the assembler syntax as "Plan9" throughout the text and title and they talk about "x86 Plan9" and "arm Plan9".

Considering there is no introduction at all to this beyond "I discovered it's called Plan9", I'm assuming the author really thinks this is a language widely named "Plan9".

They seem to be badly mistaken

That seems to be the case: https://news.ycombinator.com/item?id=41880346

> IIRC before Go was self compiling, it was compiled using 9c, and its architecture inherits from 9c.

Back in those days I actually found that, with a few small tweaks, I could compile the Plan 9 operating system using Go's C suite. We didn't pursue it further but this was one of the options we looked into for cross-compiling Plan 9 from other operating systems.

Since to Go C suite was ported Plan 9 compilers, I'm not sure why this would be a surprise. Since I'm obviously missing something would you share your thoughts on what challenges you expected?

It wasn't any surprise, nor did I intend to imply it was surprising, just relaying an anecdote. There were a few differences that required small tweaks to the source, but we got the Plan 9 kernel compiled with the Go C compilers in a day.