file read dates

[Chris Torek]

In article <183 at magic.ARPA> stewart at magic.UUCP (Larry Stewart) writes:

> Who looks at file read dates?

Anyone who wants to.

> Do any more-or-less standard Unix applications look at them?

E.g., ls -l, make:  Yes.

> Are they worth the trouble of maintaining?

Yes.

> For example, a literal interpretation of the semantics of file
> read dates in Unix would require that the inode for a directory
> be re-written every time the directory was scanned for a file...

Only the in-core copy need be updated immediately.  At sync() or
in-core inode reuse, the disk copy needs to be updated.

> Since one can mount a file system read-only, I presume this is not
> always done.

True enough.  This is merely a matter of priority:  You have to
assume that being mounted read-only is more important than having
the access times updated.

`Them's the breaks.'
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1415)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at mimsy.umd.edu