[pmwiki-users] Re: Per-group subdirectories in wiki.d/

[Joachim Durchholz]

chr at home.se wrote:
> PS. Wasn't there an old DOS limit of like 255 files per directory?

The FAT file system is incredibly bad, but that was not one of its flaws.

It *had* a fixed upper limit of file slots in the root directory. The 
exact limit could be set arbitrarily, though most formatting programs 
just used a heuristics based on media size.

However, accessing an arbitrary file in a subdirectory that held N files 
was O(N) time. Modern file systems make that O(log N).

 > What's a typical limit today on ext3 or NTFS?

No limits here.

Things can get pretty slow though. I don't know whether NTFS is in the 
O(log N) category, but ext2 and ext3 are in the O(N) category AFAIK. 
That's the reason why installations like SourceForge have their home 
directory structure set up like
   /home/a/ant
   /home/a/atlas
   ...
   /home/b/...
(I think SF even uses several levels of single-letter directories to 
keep directories to a reasonable size).

I think reiserfs and xfs are in the logarithmic category, but I'd 
double-check that information before relying on it myself.

Regards,
Jo