22 Mar
2018
22 Mar
'18
2:55 a.m.
DEC did a BASIC compiler for RSTS and RSX
BasicPlus was about the only good thing about RSTS. In fact, we were allowed to replace
the RSTS with UNIX at JHU if we could get BASIC PLUS ported over.
Fortunately, RSTS used EMT instructions for system calls (bizarre if you read the PDP-11
Processor Handbook) where as UNIX used the expected TRAP instruction. All we had to do
was add a "nostack" system call (I think we put it in, it might have already
been there) to disable UNIX's idea of how a stack should work.