:AOS: 1. /aws/ (East Coast), /ay-os/ (West Coast) [based on a 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. 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. 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.