Criticism of Atime
Writing to a file changes its mtime and ctime, while reading a file changes its atime. As a result, on a POSIX-compliant system, reading a file causes a write, which has been criticized. This behaviour can usually be disabled by adding a mount option in /etc/fstab.
However, turning off atime updating breaks POSIX compliance, and some applications, notably the Mutt mail reader (in some configurations), and some file usage watching utilities, notably tmpwatch.
Linux kernel developer Ingo Molnár called atime "perhaps the most stupid Unix design idea of all times," adding: "hink about this a bit: 'For every file that is read from the disk, let's do a ... write to the disk! And, for every file that is already cached and which we read from the cache ... do a write to the disk!'" He further emphasized the performance impact thus:
- atime updates are by far the biggest I/O performance deficiency that Linux has today. Getting rid of atime updates would give us more everyday Linux performance than all the pagecache speedups of the past 10 years, _combined_.
Read more about this topic: Stat (system Call)
Famous quotes containing the words criticism of and/or criticism:
“Cubism had been an analysis of the object and an attempt to put it before us in its totality; both as analysis and as synthesis, it was a criticism of appearance. Surrealism transmuted the object, and suddenly a canvas became an apparition: a new figuration, a real transfiguration.”
—Octavio Paz (b. 1914)
“People try so hard to believe in leaders now, pitifully hard. But we no sooner get a popular reformer or politician or soldier or writer or philosopher—a Roosevelt, a Tolstoy, a Wood, a Shaw, a Nietzsche, than the cross-currents of criticism wash him away. My Lord, no man can stand prominence these days. It’s the surest path to obscurity. People get sick of hearing the same name over and over.”
—F. Scott Fitzgerald (1896–1940)