View source for RT-11

===Source code===
RT-11 was written in [[assembly language]]. Heavy use of the conditional assembly and macro programming features of the [[MACRO-11]] assembler allowed a significant degree of configurability and allowed programmers to specify high-level instructions otherwise unprovided for in machine code. RT-11 distributions included the [[source code]] of the operating system and its device drivers with all the comments removed and a program named "SYSGEN" which would build the operating system and drivers according to a user-specified configuration. Developer's documentation included a [[kernel (operating system)|kernel]] listing that included comments.