How to stuff 7% more material into your sfs's.

[rufwoof]

LZ4 compresses less tightly (larger size), but decompresses much quicker than both gzip and xz.

Any chance you could suggest a good default syntax to build an sfs from a directory using LZ4? (and do you have any idea if LZ4 is understood by Slacko?)

I suspect its not in Slacko.

It has to be built into the kernel as well as having updated squashfs-tools ... in which mksquashfs will typically have just -comp lz4 (basic choice) or -comp lz4 -Xhc (higher compression choice (decompression speed isn't any slower, but in decompressing less due to higher compression will throughput quicker)). Compression ratio isn't good. Higher speed comes with less complexity (less compression).

mksquashfs --help will show if the squashfs-tools version you have supports lz4, but the kernel might not necessarily also support it.

[greengeek]

mksquashfs --help will show if the squashfs-tools version you have supports lz4, but the kernel might not necessarily also support it.

Thanks - looks like only gzip and xz available. cheers!

[OvrMaHd]

I would like to thank all of the contributors of this thread. Has helped tremendously, to creating functioning Make SfS, from a plethora of obscure options.

Ovr

[drunkjedi]

Hey people,

Anyone knows any way to know how a given sfs was made?

Any command or mksquashfs option to get details about the block size, xdict size, compression used, of a given sfs.

[musher0]

Hi drunkjedi.

Good question. Why do you want to know? As long as it does the job...

If you try to open a sfs file with the real less in binary mode, perhaps you can see a
kind of header? (Please see attached capture.) Now, to interpret it...

You are probably thinking of something like the zipinfo utility for the zip compressor.
I searched a bit on the Web and I have not found anything like it for squash files.

IHTH

[hamoudoudou]

compression tools
To open ISOs squash files i use UEextract..
Just to remember.
User can choose low, fast, that will give different size in resulting files.
My Opinion :compression is useful for very big files, compression makes processors work and slow down install.
A Puppy ISO compressed xz in not lighter than compressed gz, the weight would be the same, compared to one kg of feathers and one kg of iron. For old computers with only one processor, that is important not to give it work to do. (inflate the air mattress)

[nic007]

xz compression will ALWAYS produce a smaller compressed file size than gzip compression, if not, you haver done something seriously wrong somewhere (unless you are trying to compress something that has already been compressed, like an ISO with already compressed content).

[drunkjedi]

Why do you want to know? As long as it does the job...

Ohh it's just me being lazy.
I have too many sfs laying around. I don't know how they were compressed, or if there's any chance to further save space.

I searched a bit on the Web and I have not found anything like it for squash files.

I did search the web before posting, didn't find any way.

Only easy way would be to make a script that will unsquash and then re-squash given bunch of SFS with those options.

[nic007]

Why do you want to know? As long as it does the job...

Ohh it's just me being lazy.
I have too many sfs laying around. I don't know how they were compressed, or if there's any chance to further save space.

I searched a bit on the Web and I have not found anything like it for squash files.

I did search the web before posting, didn't find any way.

Only easy way would be to make a script that will unsquash and then re-squash given bunch of SFS with those options.

Right-clicking on the sfs and choosing properties from the menu will give you some description of the sfs. A block size of 1 byte (if possible) will generally indicate the highest compression. I've checked my sfs's which were compressed at maximum compression and they all report block sizes of either 1 or 2 bytes.

[musher0]

@drunkjedi:

Looking for something else, I chanced on these methods
to get info about a squashed or sfs file.

The easy way is to open a console in the directory where your sfs file is, and type:

Code: Select all

unsquash -s file.sfs

Another involves the use of dd, and another still uses

Code: Select all

strings file.sfs | head

to get "some" info.

None of these methods seem able to uncover the additional parameters used to
obtain greater compression when squashing.

IHTH.