Re: New filesystem for Linux

[H. Peter Anvin]

Maurizio Lombardi wrote:
> On 11/4/06, Mikulas Patocka <mikulas@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> > free space is organized in lists of free runs
> > and converted to bitmap only in case of
> > extreme fragmentation.
>
> There is a performance reason to prefer lists of free blocks rather than 
> bitmap?
>
> I read from [Tanenbaum: Operating System, Design and Implementation II
> ed. ] that lists are better than bitmap only when disk is almost full.

Yes, if you have a truly random access medium.

If you have media like physical disks, where fragmentation costs you, 
the lists will kill you dead in no time at all.

	-hpa
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