questions on squid cache

[Melanie Pfefer <melanie_pfefer@xxxxxxxxxxx>]

hi

I have in squid.conf

cache_dir ufs /var/squid/var/cache 100 16 256


I would like to know:
1. if the squid cache is stored on disk or RAM
2. if I can reach a point where "cache is full"
3. How can I "remove cache" older than 1 week (same logic as log rotation)

thanks in advance