spl

/SPL/ [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.

