[announce] Squashfs2.0-alpha released (compressed filesystem)

[announce] Squashfs2.0-alpha released (compressed filesystem)

[Phillip Lougher]

Hi all,

I'm pleased to announce the first version of Squashfs 2.0.  A lot of
changes to the Squashfs filesystem have been made under the bonnet
(hood), to improve compression. Squashfs 2.0 has added the concept of
fragment blocks and has increased the block size to 64K. This achieves
a 5 - 20% compression saving, and allows Squashfs to achieve better
compression than Cloop while retaining the I/O efficiency of a
compressed filesystem.  In addition, the maximum number of UIDs and
GIDs has been increased to 256. This allows Squashfs to better support
live CDs.

For a description of fragment blocks and the other changes, please go
to the project page http://squashfs.sourceforge.net.

Regards

Phil Lougher

[announce] Squashfs2.0-alpha released (compressed filesystem)

[Phillip Lougher]

Hi all,

I'm pleased to announce the first version of Squashfs 2.0.  A lot of
changes to the Squashfs filesystem have been made under the bonnet
(hood), to improve compression. Squashfs 2.0 has added the concept of
fragment blocks and has increased the block size to 64K. This achieves
a 5 - 20% compression saving, and allows Squashfs to achieve better
compression than Cloop while retaining the I/O efficiency of a
compressed filesystem.  In addition, the maximum number of UIDs and
GIDs has been increased to 256. This allows Squashfs to better support
live CDs.

For a description of fragment blocks and the other changes, please go
to the project page http://squashfs.sourceforge.net.

Regards

Phil Lougher

Re: [announce] Squashfs2.0-alpha released (compressed filesystem)

[Pat LaVarre]

> http://squashfs.sourceforge.net
> increased the block size to 64K ...

An aligned 64 KiB, as DVD/ CD-RW rewards in thruput?

Pat LaVarre

Re: [announce] Squashfs2.0-alpha released (compressed filesystem)

[Phillip Lougher]

On 21 May 2004 09:37:43 -0600, Pat LaVarre <p.lavarre@ieee.org> wrote:
> 
> > http://squashfs.sourceforge.net
> > increased the block size to 64K ...
> 
> An aligned 64 KiB, as DVD/ CD-RW rewards in thruput?
> 

Alignment to 64K block boundaries would impair compression.  All
filesystem objects (data, metadata etc). are packed together on a bye
alignment to maximize compression.

The increase to 64K blocks do increase I/O throughput by the simple
fact there's more data read per seek.  For CD/DVD the fragments also
tend to help by minimizing seeking to read adjacent files.

> Pat LaVarre
> 
>