[WEB4LIB] Browser cache size and maintenance

[James Klock]

>Do you go around at regular intervals and clear your browser cache files so
>your disk doesn't become clogged?  How do you handle it when it means undoing
>and redoing the security?

We're fortunate enough to have started with a policy limiting patrons to a
single, timed, half-hour session each day.  We were then able to dictate
that each session will begin (and end) on the half hour.  I set up our
Internet workstations to run a script which clears out all user-modifiable
files.
Our security system (FoolProof) allows for the designation of a single
user-modifiable directory (everywhere else on the disk is locked).  So we
don't need to disable the security program in order to remove
patron-modifiable files.

>Second, is there a recommended cache limit?  

We don't cache anything to disk on our general-use Internet workstations.
In a half-hour session, most users will either hit such a wide variety of
sites that the cache wouldn't be useful (because they won't go back to a
site) or they'll stay put on one site, and the banner and border graphics
will stay in the 4MB memory cache.  Once that patron is done with her
session, we don't want her cache around anyway (since it is a potential
privacy breach).
I've actually benchmarked this-- even when I tried to browse in such a way
that the disk cache would make a difference, I was able to generate not
more than a 12% performance increase.

One of the disadvantages of setting a relatively small disk cache is that,
once the cache is full, the files have to be deleted.  This takes time.  I
haven't used IE enough to know when it goes about deleting the cache, but
Navigator 4.x does it in the middle of browsing-- when the cache is full,
it starts looking at what documents are past their expiration date, and
starts wiping them, all while you're waiting for your browsing session to
continue...  It's a bit of a pain, but at least it tells you "Cleaning disk
cache: xxxx files" on the status bar...

That might explain some of your freezing?

James