PDP-10 increment instruction] vt.,obs. To increase the amount of
something. "AOS the campfire." Usage: considered silly, and now
obsolete. Now largely supplanted by bump. See SOS.
2. n. A Multics-derived OS supported at one time by Data
General. This was pronounced /A-O-S/ or /A-os/. 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. n. Algebraic Operating
System, in reference to those calculators which use infix instead
of postfix (reverse Polish) notation.
Historical note: AOS in sense 1 was the name of a PDP-10
instruction that took any memory location in the computer 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.