Hi: Porting Cramfs on FreeBSD

Eric Anderson anderson at centtech.com
Wed Sep 27 11:51:13 PDT 2006


On 09/27/06 12:44, Oliver Fromme wrote:
> Eric Anderson wrote:
>  > I'm currently working on a tarfs, that will do something similar to 
>  > this, except it allows you to use a regular tar file as the file system 
>  > image.
> 
> That's cool.  I'm looking forward to it.
> 
>  > I don't have compression working yet, but that is on the 
>  > roadmap. [...] large file system sizes (based on available
>  > memory)
> 
> Hm.  Does that mean that the whole (uncompressed) FS image
> will have to fit into memory?  That would be a disadvantage
> compared to cramfs.  Cramfs doesn't compress the whole FS
> as one object (like .tar.gz), but it compresses it page-by-
> page, so every page can be uncompressed independently, and
> memory usage is very low, which is good for small embedded
> applications.

No, only inode+direntries need to fit into memory.  So an FS with 
1million inodes might take .5MB of memory (estimate).

Eric



-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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