Re: IDE and locking

[Paul Jackson <pj@sgi.com>]

This doesn't answer your real question, but I can't resist
noticing that the above would be more efficient as:

  find / -type f | xargs wc >/dev/null

Several times fewer system calls, with just a few exec's of 'wc',
instead of exec'ing a 'dd' per file, and with just one read per 16 Kb,
instead of both a read and write per 512 bytes.

Granted - I'm being silly to mention this - your compact flash
device is obviously the bottleneck here.  Doesn't really matter
if the cpu spends 1% or 2% of its time outside the idle loop.


> 4. Is there a max number of files that can be cached by linux?

As long as there is no memory pressure, I suspect it keeps caching
more.

> 5. Will the files be removed at any stage from the cache
>     if there is no memory pressure?

I don't think so - stuff seems to stay in cache 'forever',
if no one else wants the memory.

> 6. Can I reserve memory for the file cache?

Not that I know of.  If it were read-only data, I might try a ram disk,
but your application apparently is read-write.

It might be (long shot, here) that just caching the directories and
inodes was enough, without caching the file contents:

  find / ! -true


-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373