sticky bit
Peter Baer Galvin
galvin-peter at yale-bulldog.arpa
Tue Feb 28 21:46:54 AEST 1989
Under Berkeley Unix an executable program is copied into system swap space
before execution is started. Paging of the program is done from swap
space rather than from the executable in the file system because
(according to Karels I think) going through the file system would take 3
times longer. When the last processes using the image exits, the image is
removed from swap. The sticky bit tells the OS not to delete the image in
swap space, even if no processes are using that image. This saves the
overhead of the copy from file system to swap space. The down side is
that the swap space is then not usable by other programs until the system
in question reboots. If you always have an emacs running (as I do) then
setting it sticky doesn't do much, one way or the other.
--Peter
Peter Baer Galvin (203)432-1254
Senior Systems Programmer, Yale Univ. C.S. galvin-peter at cs.yale.edu
51 Prospect St, P.O.Box 2158, Yale Station ucbvax!decvax!yale!galvin-peter
New Haven, Ct 06457 galvin-peter at yalecs.bitnet
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