= S =
[abbrev, from Set Priority Level] The way
traditional Unix kernels implement mutual exclusion by running code
at high interrupt levels. Used in jargon to describe the act of
tuning in or tuning out ordinary communication. Classically, spl
levels run from 1 to 7; "Fred's at spl 6 today" would mean that
he is very hard to interrupt. "Wait till I finish this; I'll spl
down then." See also interrupts locked out.
--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.