thud n.
1. Yet another metasyntactic variable (see
foo). It is reported that at CMU from
the mid-1970s the canonical series of these was `foo', `bar',
`thud', `blat'. 2. Rare term for the hash character, `#' (ASCII
0100011). See ASCII for other
synonyms.
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thumb n.
The slider on a window-system scrollbar. So called because
moving it allows you to browse through the contents of a text
window in a way analogous to thumbing through a book.
Node:thundering herd
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thundering herd problem
Scheduler thrashing. This can happen under Unix when you have
a number of processes that are waiting on a single event. When
that event (a connection to the web server, say) happens, every
process which could possibly handle the event is awakened. In the
end, only one of those processes will actually be able to do the
work, but, in the meantime, all the others wake up and contend
for CPU time before being put back to sleep. Thus the system
thrashes briefly while a herd of processes thunders through. If
this starts to happen many times per second, the performance
impact can be significant.