Compressing unix disks

Don Speck mangler at cit-vax.Caltech.Edu
Fri Apr 15 18:08:30 AEST 1988


In article <7582 at ncoast.UUCP>, allbery at ncoast.UUCP (Brandon Allbery) writes:
> you seem to need CPU to use the Berkeley FFS, and System V is popular on the
> little *nix boxes.

I've heard over and over that the Berkeley Fast Filesystem is considered a
CPU hog.  So I tried a trivial experiment, a program that does 512 writes
of 8K bytes each (enough to exceed the buffer cache) and the times were:

3B20S SysV.2,  1K fs blocksize	    32.6 real  0.0 user  11.4 sys
vax-750 4.3BSD 8K fs blocksize	     8.5 real  0.0 user   8.2 sys

BSD beat SysV in system time, even though SysV was running
on a CPU twice as fast and optimized for SysV!	So why does
everybody claim that the BSD filesystem is a CPU hog?

Don Speck   speck at vlsi.caltech.edu  {amdahl,ames!elroy}!cit-vax!speck



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