Compression algorithm in cloop
Quoted 5 lines
Hello,
I am trying to do some experiment on compression ratios with cloop. I know that currently cloop uses zlib. How can I change it to other algorithms?
Changing the algorithm from gzip is going to be probably unpopular. Cloop uses the gzip deflate library inside the kernel shared by a large number of other programs. To change the algorithm you'll have to add more (private) decompression code to the kernel. This is a retrograde step because the shared library was only introduced in 2.4.17 to avoid lots of private copies of gzip.
Quoted 2 lines
Where should I start from? Really a newbie to this, appreciate any comments and suggestions!!
There has been discussion on this list before about adding bzip2 support to the kernel. Do a search on the list for this.
Regards
Phillip
Quoted 5 lines · Phillip Lougher
Quoted 2 lines
Where should I start from? Really a newbie to this, appreciate any comments and suggestions!!
There has been discussion on this list before about adding bzip2 support to the kernel. Do a search on the list for this.
Long, long ago there was something called e2compr. They had bzip2 in the kernel. I remember 40 seconds mc start time on disk compressed with bzip2 on i486-DX 40 MHz... :-)
Grzegorz Kulewski
On Wed, 11 Aug 2004 19:21:50 +0200 (CEST) Grzegorz Kulewski wrote:
| On Wed, 11 Aug 2004, Phillip Lougher wrote: | | >> Where should I start from? Really a newbie to this, | >> appreciate any comments and suggestions!! | > | > There has been discussion on this list before about adding | > bzip2 support to the kernel. Do a search on the list for this. | | Long, long ago there was something called e2compr. They had bzip2 in the | kernel. I remember 40 seconds mc start time on disk compressed with bzip2 | on i486-DX 40 MHz... :-)
still at
http://e2compr.sourceforge.net/
--
~Randy
If I don't want to build a new compression library and port it to kernel, all I want to do is to try out the idea -- whether it could work on cloop, whether the compression ratio is acceptable, can I just change the cloop code? In other words, I just need a loopback block device with other compression scheme.
I know that adding the new algorithm support to kernel would be standard way to do this and would be helpful to more people, it's just that I don't have that time :(
Quoted 23 lines · Phillip Lougher
Quoted 5 lines
Hello,
I am trying to do some experiment on compression ratios with cloop. I know that currently cloop uses zlib. How can I change it to other algorithms?
Changing the algorithm from gzip is going to be probably unpopular. Cloop uses the gzip deflate library inside the kernel shared by a large number of other programs. To change the algorithm you'll have to add more (private) decompression code to the kernel. This is a retrograde step because the shared library was only introduced in 2.4.17 to avoid lots of private copies of gzip.
Quoted 2 lines
Where should I start from? Really a newbie to this, appreciate any comments and suggestions!!
There has been discussion on this list before about adding bzip2 support to the kernel. Do a search on the list for this.
Regards
Phillip
Quoted 2 lines · Lei Yang
If I don't want to build a new compression library and port it to kernel, all I want to do is to try out the idea -- whether it could work on cloop, whether the compression ratio is acceptable, can I just change the cloop code? In other words, I just need a loopback block device with other compression scheme.
If you just want to try out some wacky ideas, I suggest you take a look at the network block device.
It is a block device that sends all read/write requests through a socket
so that this requests can be fulfilled by a user space deamon.
This is not very good in terms of performance, but it is much easier to develop this kind of thing in userspace, without all the stack / memory / atomicity / concurrency problems :)
Signature · 2 lines
Paulo Marques - www.grupopie.com "In a world without walls and fences who needs windows and gates?"