PAL-11R is an assembly language, and an assembler, for the PDP-11's

disk operating system A disk operating system (DOS) is a computer operating system that requires a disk or other direct-access storage device as secondary storage. A DOS provides a file system and a means for loading and running computer program, programs stored on th ...

DOS-11 BATCH-11/DOS-11, also known simply as DOS-11, is a discontinued operating system by Digital Equipment Corporation (DEC) of Maynard, Massachusetts, Maynard, Massachusetts. The first version of DOS-11 (V08-02) was released in 1970 and was the first ...

. It was the precursor to MACRO-11. The original assembler for Unix, as, was based on PAL-11R.

References

PDP-11 {{compu-prog-stub