remaster knoppix with squashfs

[kelmo]

Thanks wangji, the mods worked well. The squashfs image of the KNOPPIX filesystem is ~5% smaller than that of cloop.

Busybox was simple to compile and worked well.

Rebuilt the miniroots with symbolic links to busybox(static) instead of ash, and with the loop module.

The following changes to linuxrc did the trick for Knoppix 3.4.

$INSMOD /modules/loop.o >/dev/null 2>&1
mount -t squashfs /$1/$KNOPPIX_DIR/$KNOPPIX_NAME /KNOPPIX -o loop,ro ||

Only problem:-
The cd is not ejected before shutdown. Where do you suppose cloop is mentioned in other scripts? SysV-init scripts?

[wangji]

hi kelmo,
this cdeject at halt is handled by /etc/init.d/knoppix-halt
it has nothing to do with cloop !!!I am not 100% sure ,but I suspect rather the problem of "cd not eject" related ...with
kernel-2.6.x_cdATAPI_cd_fake_scsi.
Just to put a hint : if you allow dma at boot for cdreader,some
knoppix_like distro don't boot at all (no matter which compression used) the /dev/scdi ...not detected and you hang .
(This is not the kernel fault but rather ...poor mechanics design,
-price is so low !!-errors bursts -irq,dusts...-and perhaps too weak
Reed Solomon implementations ,-not more than 5 errors per sector_read-.).In those specific cases just type at boot:
knoppix nodma ...
and the miracle operates
But of course I do not help you solve the cd ejection !!!
Type as root : cdrecord -eject dev=x,x,x
works,even if you had boot a livecd,
that's a very poorman solution.

[kelmo]

No big problem. I really like the simplicity of remastering using squashfs.

I wish a debian packager would put the latest squashfs-tools in a .deb.

Wangji, can you give me any tips of what options can be used to 'optimize' the compressed filesystem with mksquashfs. At the moment I am using the basic command:-

mksquashfs {source} {target}

This works fine, but I'd like to experiment with sorting the filesystem to squeeze every last bit of performance out of it.

Thanks

[wangji]

I am sure I do not know the real answer !! but I try to summarises my "feelings" .In older version ,ie squashfs-1.3 the
indexing pointer scheme was clever and allow very fast stuffs ;
but if you compress the huge_knoppix_2.2Gb then you get into trouble : that's why version 2 from Philip Lougher ! but I understand then it compresses almost in blocks "exactly as cloop"
(with probably variations ,tree structure...giving this ~5% diff)
Arranging big files at the beginning may help readout response time ,but that is related to how iso files,cdreader behave(in case of cloop) I believe you gain nothing with squashfs (we have to ask Philip at his forum).The true point I like mksquashfs is that you
are not bound to put the whole stuff in a "remastering_directory" since you can put exclude_options (I am using that way a lot)If you need response time,I believe mkztree
should be faster (however poor compression ,since block size vary a lot depending on your applications !!! remember zisofs,was included long time ago into kernel -politically correct put aside !!-)