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Back door --- Backbone site
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Back door
--- back door: n. A hole in the security of a system deliberately left
in place by designers or maintainers. The motivation for this is not always sinister; some operating systems, for
example, come out of the box with privileged accounts intended for use by field service technicians or the vendor's
maintenance programmers.
Backbone --- A
high-speed line or series of connections that forms a major pathway within a network. The term is relative as a
backbone in a small network will likely be much smaller than many non-backbone lines in a large network.
See Also: Network
Backbone cabal ---
backbone cabal: n. A group of large-site administrators who pushed through the Great Renaming and reined
in the chaos of USENET during most of the 1980s. The cabal mailing list disbanded in late 1988 after a bitter internal
catfight, but the net hardly noticed.
Backbone site ---
backbone site: n. A key USENET and email site; one that processes a large amount of third-party traffic,
especially if it is the home site of any of the regional coordinators for the USENET maps. Notable backbone sites
as of early 1991 include uunet and the mail machines at Rutgers University, UC Berkeley, DEC's Western Research
Laboratories, Ohio State University, and the University of Texas. Compare rib site, leaf site.
Historically, back doors have often lurked in systems longer than anyone expected or planned, and a few have
become widely known. The infamous RTM worm of late 1988, for example, used a back door in the BSD UNIX `sendmail(8)'
utility.
Ken Thompson's 1983 Turing Award lecture to the ACM revealed the existence of a back door in early UNIX versions
that may have qualified as the most fiendishly clever security hack of all time. The C compiler contained code
that would recognize when the `login' command was being recompiled and insert some code recognizing a password
chosen by Thompson, giving him entry to the system whether or not an account had been created for him.
Normally such a back door could be removed by removing it from the source code for the compiler and recompiling
the compiler. But to recompile the compiler, you have to *use* the compiler --- so Thompson also arranged that
the compiler would *recognize when it was compiling a version of itself*, and insert into the recompiled compiler
the code to insert into the recompiled `login' the code to allow Thompson entry --- and, of course, the code to
recognize itself and do the whole thing again the next time around! And having done this once, he was then able
to recompile the compiler from the original sources, leaving his back door in place and active but with no trace
in the sources.
The talk that revealed this truly moby hack was published as "Reflections on Trusting Trust", `Communications
of the ACM 27', 8 (August 1984), pp. 761--763.
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Backgammon --- Backplane
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Backgammon --- backgammon:
See bignum, moby, and pseudoprime.
Background ---
background: n.,adj.,vt. To do a task `in background' is to do it whenever foreground matters are not
claiming your undivided attention, and `to background' something means to relegate it to a lower priority. "For
now, we'll just print a list of nodes and links; I'm working on the graph-printing problem in background."
Note that this implies ongoing activity but at a reduced level or in spare time, in contrast to mainstream `back
burner' (which connotes benign neglect until some future resumption of activity). Some people prefer to use the
term for processing that they have queued up for their unconscious minds (a tack that one can often fruitfully
take upon encountering an obstacle in creative work). Compare amp off, slopsucker.
Technically, a task running in background is detached from the terminal where it was started (and often running
at a lower priority); oppose foreground. Nowadays this term is primarily associated with UNIX,
but it appears to have been first used in this sense on OS/360.
Background operation --- A job performed by a program when another program is in the active window. For example,
printing or creating a backup can be done by Windows 95 as a background operation.
Backplane ---
A circuit board containing sockets into which other circuit boards can be plugged in. In the context
of PCs, the term backplane refers to the large circuit board that contains sockets forexpansion cards.
Backplanes are often described as being either active or passive. Active backplanes contain, in addition to the
sockets, logical circuitry that performs computing functions. In contrast, passive backplanes contain almost no
computing circuitry.
Traditionally, most PCs have used active backplane. Indeed, the terms motherboard and backplane have been synonymous.
Recently, though, there has been a move toward passive backplanes, with the active components such as the CPU inserted
on an additional card. Passive backplanes make it easier to repair faulty components and to upgrade to new components.
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Backspace and overstrike ---
Bag on the side
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Backspace and overstrike --- backspace and overstrike: interj. Whoa! Back up. Used to suggest that someone
just said or did something wrong. Common among APL programmers.
Backup ---
A program that comes with Windows 95 and enables the user to back up the files from a hard disk to a
floppy disk, tape drive, or another computer on a network.
Backup set --- The set of duplicate files and folders created by a backup program (see "Backup").
This set is stored on tapes, diskettes, or other storage medium that can be removed and stored safely away from
your computer. See Full System Backup.
Backward
combatability --- backward combatability: /bak'w*rd k*m-bat'*-bil'*-tee/
[from `backward compatibility'] n. A property of hardware or software revisions in which previous protocols, formats,
and layouts are discarded in favor of `new and improved' protocols, formats, and layouts. Occurs usually when making
the transition between major releases. When the change is so drastic that the old formats are not retained in the
new version, it is said to be `backward combatable'. See flag day.
BAD --- BAD:
/B-A-D/ [IBM: acronym, `Broken As Designed'] adj. Said of a program that is bogus because of bad design and misfeatures
rather than because of bugginess. See working as designed.
Bad Thing ---
Bad Thing: [from the 1930 Sellar & Yeatman parody `1066 And All That'] n. Something that can't possibly
result in improvement of the subject. This term is always capitalized, as in "Replacing all of the 9600-baud
modems with bicycle couriers would be a Bad Thing". Oppose Good Thing. British correspondents confirm that
Bad Thing and Good Thing (and prob. therefore Right Thing and Wrong Thing) come from the book referenced in the
etymology, which discusses rulers who were Good Kings but Bad Things. This has apparently created a mainstream
idiom on the British side of the pond.
Bag on the side ---
bag on the side: n. An extension to an established hack that is supposed to add some functionality to
the original. Usually derogatory, implying that the original was being overextended and should have been thrown
away, and the new product is ugly, inelegant, or bloated. Also v. phrase, `to hang a bag on the side [of]'. "C++?
That's just a bag on the side of C ...." "They want me to hang a bag on the side of the accounting system."
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Bagbiter --- Bang
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Bagbiter --- bagbiter:
/bag'bi:t-*r/ n. 1. Something, such as a program or a computer, that fails to work, or works in a remarkably clumsy
manner. "This text editor won't let me make a file with a line longer than 80 characters! What a bagbiter!"
2. A person who has caused you some trouble, inadvertently or otherwise, typically by failing to program the computer
properly. Synonyms: loser, cretin, chomper. 3. adj. `bagbiting' Having the quality of a bagbiter. "This bagbiting
system won't let me compute the factorial of a negative number." Compare losing, cretinous, bletcherous, `barfucious'
(under barfulous) and `chomping' (under chomp). 4. `bite the bag' vi. To fail in some manner. "The computer
keeps crashing every 5 minutes." "Yes, the disk controller is really biting the bag." The original
loading of these terms was almost undoubtedly obscene, possibly referring to the scrotum, but in their current
usage they have become almost completely sanitized.
A program called Lexiphage on the old MIT AI PDP-10 would draw on a selected victim's bitmapped terminal the words
"THE BAG" in ornate letters, and then a pair of jaws biting pieces of it off. This is the first and to
date only known example of a program *intended* to be a bagbiter.
Bamf --- bamf:
/bamf/ 1. [from old X-Men comics] interj. Notional sound made by a person or object teleporting in or out of the
hearer's vicinity. Often used in virtual reality (esp. MUD) electronic fora when a character wishes to make a dramatic
entrance or exit. 2. The sound of magical transformation, used in virtual reality fora like sense 1. 3. [from `Don
Washington's Survival Guide'] n. Acronym for `Bad-Ass Mother Fucker', used to refer to one of the handful of nastiest
monsters on an LPMUD or other similar MUD.
Banana label ---
banana label: n. The labels often used on the sides of macrotape reels, so called because they are shaped
roughly like blunt-ended bananas. This term, like macrotapes themselves, is still current but visibly headed for
obsolescence.
Banana problem ---
banana problem: n. [from the story of the little girl who said "I know how to spell `banana', but
I don't know when to stop"]. Not knowing where or when to bring a production to a close (compare fencepost
error). One may say `there is a banana problem' of an algorithm with poorly defined or incorrect termination conditions,
or in discussing the evolution of a design that may be succumbing to featuritis (see also creeping elegance, creeping
featuritis). See item 176 under HAKMEM, which describes a banana problem in a Dissociated Press implementation.
Bandwidth ---
How much stuff you can send through a connection. Usually measured in bits-per-second. A full page of
English text is about 16,000 bits. A fast modem can move about 15,000 bits in one second. Full-motion full-screen
video would require roughly 10,000,000 bits-per-second, depending on compression.
See Also: 56k Line , Bps , Bit , T-1
Bang
--- ! - An exclamation point used to signify surprise in an online
foru.
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Bang on --- Bare metal
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Bang on
--- bang on: vt. To stress-test a piece of hardware or software:
"I banged on the new version of the simulator all day yesterday and it didn't crash once. I guess it is ready
to release." The term pound on is synonymous.
Bang
path --- bang path: n. An old-style UUCP electronic-mail
address specifying hops to get from some assumed-reachable location to the addressee, so called because each hop
is signified by a bang sign. Thus, for example, the path ...!bigsite!foovax!barbox!me directs people to route their
mail to machine bigsite (presumably a well-known location accessible to everybody) and from there through the machine
foovax to the account of user me on barbox.
In the bad old days of not so long ago, before autorouting mailers became commonplace, people often published compound
bang addresses using the { } convention (see glob) to give paths from *several* big machines, in the hopes that
one's correspondent might be able to get mail to one of them reliably (example: ...!{seismo, ut-sally, ihnp4}!rice!beta!gamma!me).
Bang paths of 8 to 10 hops were not uncommon in 1981. Late-night dial-up UUCP links would cause week-long transmission
times. Bang paths were often selected by both transmission time and reliability, as messages would often get lost.
See Internet address, network, the, and sitename.
Banner ---
Information given to you when you log into or otherwise access a system.
Bar --- bar:
/bar/ n. 1. The second metasyntactic variable, after foo and before baz. "Suppose we have two functions: FOO
and BAR. FOO calls BAR...." 2. Often appended to foo to produce foobar.
Bare metal --- bare
metal: n. 1. New computer hardware, unadorned with such snares and delusions as an operating system, an HLL, or
even assembler. Commonly used in the phrase `programming on the bare metal', which refers to the arduous work of
bit bashing needed to create these basic tools for a new machine. Real bare-metal programming involves things like
building boot proms and BIOS chips, implementing basic monitors used to test device drivers, and writing the assemblers
that will be used to write the compiler back ends that will give the new machine a real development environment.
2. `Programming on the bare metal' is also used to describe a style of hand-hacking that relies on bit-level peculiarities
of a particular hardware design, esp. tricks for speed and space optimization that rely on crocks such as overlapping
instructions (or, as in the famous case described in appendix A, interleaving of opcodes on a magnetic drum to
minimize fetch delays due to the device's rotational latency). This sort of thing has become less common as the
relative costs of programming time and machine resources have changed, but is still found in heavily constrained
environments such as industrial embedded systems. See real programmer.
In the world of personal computing, bare metal programming (especially in sense 1 but sometimes also in sense 2)
is often considered a Good Thing, or at least a necessary thing (because these machines have often been sufficiently
slow and poorly designed to make it necessary; see ill-behaved). There, the term usually refers to bypassing the
BIOS or OS interface and writing the application to directly access device registers and machine addresses. "To
get 19.2 kilobaud on the serial port, you need to get down to the bare metal." People who can do this sort
of thing are held in high regard.
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