OS tests: Linux proves to be one of the most stable
I enclose the abstract from a talk that Bart Miller will be giving
today in our Computer Sciences Department. It is interesting to note
that in this series of tests Linux proved to be one of the most stable
versions of Unix, more stable than commercial versions. He lists the
GNU utilities as a separate entry. I think that means that he is
testing the GNU utilities compiled on systems other than GNU/Linux.
His web page
may contain more information on the study.
Douglas Bates firstname.lastname@example.org
Statistics Department 608/262-2598
University of Wisconsin - Madison http://www.stat.wisc.edu/~bates/
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Date: Mon, 13 Oct 1997 06:00:09 -0500 (CDT)
From: "CS Dept. Talks" <email@example.com>
Subject: Today's Events
2:30 pm, 2310 CS
Operating Systems and Networking Seminar: Barton P. Miller, University of
Wisconsin, Madison, "Making Programs Explode: Using Simple Random Testing on
In 1990, we published the results of a study of the reliability of
standard UNIX utility programs. This study showed that by using simple
(almost simplistic) random testing techniques, we could crash or hang 25-33%
of the these utility programs. Recently, we repeated and significantly
extended this study using the same basic techniques: subjecting programs to
random input streams. A distressingly large number of UNIX utilities still
crash with our tests.
We tested a wide variety of utility programs on nine UNIX platforms.
The programs were sent random input streams. We used a conservative and
crude measure of reliability: a program is considered unreliable if it
crashes with a core dump or hangs (infinite loop). We used the random test-
ing to also test X-Window applications and servers, network servers, and
system library interfaces.
The major results of this study are: (1) In the last five years, all
previously-tested versions of UNIX made noticeable improvements in the reli-
ability of their utilities. But ... the failure rate of these systems is
still distressingly high (from 18-23% in the recent study). (3) Even worse
is that many of the same bugs that we reported in 1990 are still present in
the recent code releases. (4) The failure rate of utilities on the commer-
cial versions of UNIX that we tested (from Sun, IBM, SGI, DEC, and NEXT)
ranged from 15 to 43%. (5) The failure rate of the utilities on the freely-
distributed Linux version of UNIX was second-lowest, at 9%. (6) The failure
rate of the public GNU utilities was the lowest in our study, at only 7%.
(7) We could not crash network services on any of the versions of UNIX that
we tested. (8) Almost 60% of the X-Window applications that we tested crash
or hang on purely random input data streams (random binary data). More sig-
nificant is that more than 25% of the applications crash or hang given ran-
dom, but legal X-event streams. (9) We could not crash X server on the ver-
sions of UNIX that we tested (i.e., sending random data streams to the
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