From: Jeff Garzik <jgarzik@pobox.com>
To: Phillip Lougher <phillip@lougher.demon.co.uk>
Cc: Samuel Flory <sflory@rackable.com>, linux-kernel@vger.kernel.org
Subject: Re: ANNOUNCEMENT: Squashfs released (a highly compressed filesystem)
Date: Tue, 29 Oct 2002 23:03:20 -0500 [thread overview]
Message-ID: <3DBF5A08.9090407@pobox.com> (raw)
In-Reply-To: 3DBF5756.2010702@lougher.demon.co.uk
Phillip Lougher wrote:
> Samuel Flory wrote:
>
>> Phillip Lougher wrote:
>>
>>> Hi,
>>>
>>> First release of squashfs. Squashfs is a highly compressed
>>> read-only filesystem for Linux (kernel 2.4.x). It uses zlib
>>> compression to compress both files, inodes and directories. Inodes
>>> in the system are very small and all blocks are packed to minimise
>>> data overhead. Block sizes greater than 4K are supported up to a
>>> maximum of 32K.
>>>
>>> Squashfs is intended for general read-only filesystem use, for
>>> archival use, and in embedded systems where low overhead is needed.
>>>
>>> Squashfs is available from http://squashfs.sourceforge.net.
>>>
>>> The patch file is currently against 2.4.19. There is further info
>>> on the filesystem design etc. in the README.
>>>
>>> I'l be interested in getting any feedback, advice etc. on it.
>>>
>>
>> What are the advantages of squashfs vs cramfs?
>>
>>
>>
>
> Cramfs was the inspiration for squashfs. Squashfs basically gives
> better compression, bigger files/filesystem support, and more inode
> information.
>
> 1. Blocks upto 32K are supported - data is compressed in units of 32K
> which achieves better compression ratios than compressing in 4K
> blocks. Generally using bigger than 4K blocks are a bad idea, because
> the VFS calls the filesystem in 4K pages. Squashfs explictly pushes
> the extra block data into the page cache.
I'm curious if you looked at ntfs-tng's code before implementing this.
It's pretty darned optimal...
> 2. Squashfs compresses inode and directory information in addition to
> file data. Inodes/directories generally compress down to 50%, or say
> on average 8 bytes or less per inode.
squashfs or mksquashfs?
A r/w compressed filesystem would be darned useful too :)
Jeff
next prev parent reply other threads:[~2002-10-30 3:57 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-30 2:29 ANNOUNCEMENT: Squashfs released (a highly compressed filesystem) Phillip Lougher
2002-10-30 3:10 ` Samuel Flory
2002-10-30 3:51 ` Phillip Lougher
2002-10-30 4:03 ` Jeff Garzik [this message]
2002-10-30 4:11 ` Larry McVoy
2002-10-30 4:15 ` Jeff Garzik
2002-10-30 14:53 ` Jesse Pollard
2002-10-30 15:10 ` Padraig Brady
2002-10-30 15:42 ` Denis RICHARD
2002-10-31 16:18 ` Nicholas Wourms
2002-10-30 23:56 ` Phillip Lougher
2002-11-01 15:57 ` Rob Landley
2002-11-02 8:57 ` Phillip Lougher
2002-10-30 6:28 ` Ingo Oeser
2002-10-31 4:08 ` Phillip Lougher
-- strict thread matches above, loose matches on Subject: below --
2002-10-30 14:17 Matthew Wilcox
2002-10-31 5:12 Phillip Lougher
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