sticky bit obsolete?

[bobm at convexs.UUCP]

Devine at vianet writes:
>   Here is a question to people porting UNIX (and derivatives) to fast
> machines:  is the sticky bit idea worthwhile?   That is, on machines
> with slow disks it was worth keeping the text in the swap area, but,
> with faster disks and more memory, has the sticky bit become obsolete?

The relevant parameter is not the speed of the disks, but the relative
speeds of swap I/O and filesystem I/O.  Sticky programs are read from
the swap volume instead of the file system.  Sticky programs on VM
systems are paged in from the swap volume.  Program segments are stored
contiguously on the swap volume.

Since Berkeley unix has the Fast File System and VM, the sticky bit is
obsolete for bsd systems.  But the sticky bit is still useful in AT&T
unix, because filesystem disk access time under AT&Tnix is dominated
by seek time.

					K<bob>

deep_thought()				Bob Miller
{					Convex Computer Corporation
    sleep(years_to_seconds(7500000));	Richardson, Texas
    return 42;
}					{ihnp4,cbosgd,allegra,sun}!convex!bobm

Disclaimer: The above is not just the opinion of the author; it is the opinion
of all sentient beings in this universe and all other known universes.  The
author's employer may, however, not be sentient.