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software rot
(foldoc) | software rot
The tendency of software that has not been used
in a while to fail; such failure may be semi-humorously
ascribed to bit rot. More commonly, "software rot" strikes
when a program's assumptions become out of date. If the
design was insufficiently robust, this may cause it to fail
in mysterious ways.
For example, owing to shortsightedness in the design of some
COBOL programs, many would have succumbed to software rot when
their 2-digit year counters wrapped around at the beginning of
the year 2000. A related incident made the news in 1990, when
a gentleman born in 1889 applied for a driver's licence
renewal in Raleigh, North Carolina. The system refused to
issue the card, probably because with 2-digit years the ages
101 and 1 cannot be distinguished.
Historical note: Software rot in an even funnier sense than
the mythical one was a real problem on early research
computers (e.g. the R1; see grind crank). If a program
that depended on a peculiar instruction hadn't been run in
quite a while, the user might discover that the opcodes no
longer did the same things they once did. ("Hey, so-and-so
needs an instruction to do such-and-such. We can snarf this
opcode, right? No one uses it.")
Another classic example of this sprang from the time an MIT
hacker found a simple way to double the speed of the
unconditional jump instruction on a PDP-6, so he patched the
hardware. Unfortunately, this broke some fragile timing
software in a music-playing program, throwing its output out
of tune. This was fixed by adding a defensive initialisation
routine to compare the speed of a timing loop with the
real-time clock; in other words, it figured out how fast the
PDP-6 was that day, and corrected appropriately.
[Jargon File]
(2002-02-22)
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software rot
(jargon) | software rot
n.
Term used to describe the tendency of software that has not been used in a
while to lose; such failure may be semi-humorously ascribed to bit rot.
More commonly, software rot strikes when a program's assumptions become out
of date. If the design was insufficiently robust, this may cause it to
fail in mysterious ways. Syn. code rot. See also link rot.
For example, owing to endemic shortsightedness in the design of COBOL
programs, a good number of them succumbed to software rot when their
2-digit year counters underwent wrap around at the beginning of the year
2000. Actually, related lossages often afflict centenarians who have to
deal with computer software designed by unimaginative clods. One such
incident became the focus of a minor public flap in 1990, when a gentleman
born in 1889 applied for a driver's license renewal in Raleigh, North
Carolina. The new system refused to issue the card, probably because with
2-digit years the ages 101 and 1 cannot be distinguished.
Historical note: Software rot in an even funnier sense than the mythical
one was a real problem on early research computers (e.g., the R1; see {
grind crank}). If a program that depended on a peculiar instruction hadn't
been run in quite a while, the user might discover that the opcodes no
longer did the same things they once did. (“Hey, so-and-so needs an
instruction to do such-and-such. We can snarf this opcode, right? No one
uses it.”) Another classic example of this sprang from the time an MIT
hacker found a simple way to double the speed of the unconditional jump
instruction on a PDP-6, so he patched the hardware. Unfortunately, this
broke some fragile timing software in a music-playing program, throwing its
output out of tune. This was fixed by adding a defensive initialization
routine to compare the speed of a timing loop with the real-time clock; in
other words, it figured out how fast the PDP-6 was that day, and corrected
appropriately.
Compare bit rot.
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