sticky bit
was-John McMillan
jcm at mtunb.ATT.COM
Tue Jan 10 03:58:05 AEST 1989
In article <14750 at cisunx.UUCP> jcbst3 at unix.cis.pittsburgh.edu (James C. Benz) writes:
...
>I would like to know if :
>1) this will really help speed things up
Setting Sticky Bit [SB] ONLY locks programs' SHARED-TEXT images
on the SWAP disk.
a) It cannot hasten loading of DATA space.
b) It is UNNECESSARY for programs which typically have another
incarnation ALREADY RUNNING.
Ex: It is usually worthless for SH because the user
typically is already running that program and
its TEXT is ALREADY on the SWAP disk.
c) It is irrelevant for TINY programs whose first block and data
blocks have to be read anyway.
>2) if there are any security problems or potential problems
A SB-program consumes SWAP SPACE for its TEXT even when it it
not running. Therefore, you are that much closer to running out
of SWAP SPACE -- which is REPORTED as "ENOMEM" -- outta memory --
when it occurs.
>3) is there a limit to how much can be stored in the swap space (of course!)
> and is there a way of increasing it if necessary
Re-defining your partitions/filesystems is little fun if the
disk is large and your backup media are small :+)
>4) any other dangers like system crashes, lock up, etc you can think of
See 2). Also: each SB-program takes up a TEXT-table entry in
the kernel -- so re-tuning (NTEXT?) may be appropriate if you're
doing more than 1 or 2.
First time around, most folk seem to overdo the Sticky-Bit use.
jc mcmillan -- att!mtunb!jcm -- muttering for himzelf, only.
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