AOS
1. /aws/ (East Coast), /ay-os/ (West Coast) A
PDP-10 instruction that took any memory location and added 1 to
it. AOS meant "Add One and do not Skip". Why, you may ask, does
the "S" stand for "do not Skip" rather than for "Skip"? Ah, here
was a beloved piece of PDP-10 folklore. There were eight such
instructions: AOSE added 1 and then skipped the next instruction
if the result was Equal to zero; AOSG added 1 and then skipped if
the result was Greater than 0; AOSN added 1 and then skipped if
the result was Not 0; AOSA added 1 and then skipped Always; and so
on. Just plain AOS didn't say when to skip, so it never skipped.
For similar reasons, AOJ meant "Add One and do not Jump".
Even more bizarre, SKIP meant "do not SKIP"! If you wanted to
skip the next instruction, you had to say "SKIPA". Likewise,
JUMP meant "do not JUMP"; the unconditional form was JUMPA.
However, hackers never did this. By some quirk of the 10's
design, the JRST (Jump and ReSTore flag with no flag
specified) was actually faster and so was invariably used.
Such were the perverse mysteries of assembler programming.
2. /A-O-S/ or /A-os/ A Multics-derived
operating system supported at one time by Data General.
A spoof of the standard AOS system administrator's manual
("How to Load and Generate your AOS System") was created,
issued a part number, and circulated as photocopy folklore; it
was called "How to Goad and Levitate your CHAOS System".
3. Algebraic Operating System, in reference to
those calculators which use infix operators instead of
postfix notation.
[Jargon File]
(1995-11-26)
|