chown (was: at files and permissions)

[Peter da Silva]

In article <34515 at bu-cs.BU.EDU>, bzs at bu-cs.BU.EDU (Barry Shein) writes:
> >And big systems need better mechanisms than quotas.

> Being as a quota system isn't a whole lot more than managing a few
> integers I'd be curious to hear what would be needed to improve the
> current system (sincerely, not a snide remark!)

Well, the basic problem with quotas is the same as with such things as hard
CPU time limits. The set of problems for which they're an adequate solution
is smaller than the set of problems they're used for.

How do you allocate quotas? sum(all quotas) == free space on disk? Then you
might as well give each user a seperate partition. sum(all quotas) < free
space? Then you can still run out of disk space. In either case someone who
needs more space temporarily is out of luck... even if there's more space on
the disk.

How do quotas mesh with multiple partitions?

When I was at Berkeley the usual way to get around quotas was to mail files
to yourself, or to create subdirectories in /tmp.

I would recommend checking quotas on logout only. That can be done in an
automatic fashion, without actually putting policy in the kernel. If the
user is over quota give them a chance to delete files (or whatever) by
starting up a new shell.

Don't try to make the quota system unbreakable. If someone wants to be a
bad boy, you'll catch them. Don't burn honest users... you're not a cop.
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Business: peter at ficc.uu.net, +1 713 274 5180. | Th-th-th-that's all folks...
Personal: peter at sugar.hackercorp.com.   `-_-' |  -- Mel Blanc
Quote: Have you hugged your wolf today?  'U`  |     May 30 1908 - Jul 10 1989