security (By analogy with biological viruses, via SF) A
program or piece of code written by a cracker that "infects"
one or more other programs by embedding a copy of itself in
them, so that they become Trojan horses. When these
programs are executed, the embedded virus is executed too,
thus propagating the "infection". This normally happens
invisibly to the user.

A virus has an "engine" - code that enables it to propagate
and optionally a "payload" - what it does apart from
propagating. It needs a "host" - the particular hardware and
software environment on which it can run and a "trigger" - the
event that starts it running.

Unlike a worm, a virus cannot infect other computers without
assistance. It is propagated by vectors such as humans
trading programs with their friends (see SEX). The virus
may do nothing but propagate itself and then allow the program
to run normally. Usually, however, after propagating silently
for a while, it starts doing things like writing "cute"
messages on the terminal or playing strange tricks with the
display (some viruses include display hacks). Viruses
written by particularly antisocial crackers may do
irreversible damage, like deleting files.

By the 1990s, viruses had become a serious problem, especially
among IBM PC and Macintosh users (the lack of security on
these machines enables viruses to spread easily, even
infecting the operating system). The production of special
antivirus software has become an industry, and a number of
exaggerated media reports have caused outbreaks of near
hysteria among users. Many lusers tend to blame
*everything* that doesn't work as they had expected on virus
attacks. Accordingly, this sense of "virus" has passed into
popular usage where it is often incorrectly used for a worm
or Trojan horse.


sex

/seks/ [Sun Users' Group & elsewhere] 1. Software EXchange. A
technique invented by the blue-green algae hundreds of
millions of years ago to speed up their evolution, which had
been terribly slow up until then. Today, SEX parties are
popular among hackers and others (of course, these are no
longer limited to exchanges of genetic software). In general,
SEX parties are a Good Thing, but unprotected SEX can
propagate a virus. See also pubic directory.

2. The mnemonic often used for Sign EXtend, a machine
instruction found in the PDP-11 and many other
architectures. The RCA 1802 chip used in the early Elf
and SuperElf personal computers had a "SEt X register" SEX
instruction, but this seems to have had little folkloric
impact.

DEC's engineers nearly got a PDP-11 assembler that used
the "SEX" mnemonic out the door at one time, but (for once)
marketing wasn't asleep and forced a change. That wasn't the
last time this happened, either. The author of "The Intel
8086 Primer", who was one of the original designers of the
Intel 8086, noted that there was originally a "SEX"
instruction on that processor, too. He says that Intel
management got cold feet and decreed that it be changed, and
thus the instruction was renamed "CBW" and "CWD" (depending on
what was being extended). The Intel 8048 (the
microcontroller used in IBM PC keyboards) is also missing
straight "SEX" but has logical-or and logical-and instructions
"ORL" and "ANL".

The Motorola 6809, used in the UK's "Dragon 32" personal
computer, actually had an official "SEX" instruction; the
6502 in the Apple II with which it competed did not.
British hackers thought this made perfect mythic sense; after
all, it was commonly observed, you could (on some theoretical
level) have sex with a dragon, but you can't have sex with an
apple.


Other definitions can be found in the Jargon File