Re: ANNOUNCEMENT: Squashfs released (a highly compressed filesystem)

Phillip Lougher
2002-10-31T04:07:09Z

Ingo Oeser wrote:
> On Wed, Oct 30, 2002 at 03:51:50AM +0000, Phillip Lougher wrote:
>
>>File sizes upto 2^32 are supported.
>
> Why limiting to 2GB? AFAIR you wanted to use a cramfs-like
> filesystem for backups. Are videos and large data bases not worth
> of backing up?
>

Why are files limited to 4GB? (2^32). Simply because I never
thought anything bigger was needed :-) Initially files were limited to
2^24 (like cramfs), but because of compressed metadata I thought I could
justify an extra 8 bits in the inode, in consideration of the
extra functionality.

Going from 32 bits to 40 bits say is a bigger jump - an extra
2 bytes per file inode (1 byte for the extra file size, and 1
byte because the file start block pointer must increase
by 1 byte as well). Considering the fact I've tried to squeeze
every last byte out...

However, I could add the extra two bytes if people thought
it was worth it.

Alternatively, squashfs uses different inodes per file type. I could
add an extra "big file" type to deal with files bigger than 4GB. This
would mean > 4GB files are supported, with only one extra byte per inode
for smaller files. I'll think about it...

> It seems to be good work. So I really wait for Al Viros comments ;-)

Thanks!

Phillip

> Regards
>
> Ingo Oeser