System V file systems

[Henry Spencer]

In article <Oct.25.22.42.50.1988.1890 at geneva.rutgers.edu> hedrick at geneva.rutgers.edu (Charles Hedrick) writes:
>(2) System V (at least SVr2, and I think also SVr3) uses a free list,
>which it does not keep in order, so an active file system fragments
>very soon.  The BSD file system is designed to avoid fragmentation.
>Of course this problem will not show if you do your tests right after
>creating the file system.

Or if you run your tests in a time-sharing environment, where the disk
heads are always on their way to somewhere else anyway.  If you read
the fine print, all the Berkeley performance tests were run single-user!!
We conjectured a long time ago that the only feature of the 4.2 filesystem
that matters much in a timesharing environment is the big block size; I
haven't yet seen any solid results (numbers, not anecdotes) that would
contradict this.
-- 
The dream *IS* alive...         |    Henry Spencer at U of Toronto Zoology
but not at NASA.                |uunet!attcan!utzoo!henry henry at zoo.toronto.edu