pk stuff

Simple write test: dd bs=1M count=1000 if=/dev/zero of=test
Ignore first run results
Copy of 13,000+ files: cp -a /var/* …

O/S	Test	Raspberry Pi	Cubieboard
android (busybox to nvram)			4.8 M/B/s
berryboot (raspbian squashfs) 4G(c4)
	200M	16 +/- .5MB/s	7.8 +/- .1 MB/s
	1G	11 +/- .5MB/s	8.3 +/- 1 MB/s
	200M to SATA HD		63 +/- 2MB/s
	1G to SATA HDD		45 +/- 2MB/s
	13,727 files (/usr) from SD -> HDD (ext4)		9.2 sec
	13,727 files (/usr) from HDD -> SD		38 sec
debian (drazbian) 16G(c10)
	200M	22 +/- 2 MB/s
	1G	7.6 +/- .5 MB/s

Raspberry Pi (and Cubieboard) SD disk images typically have two (or three) partitions: the first is Fat32 (50-100MB) and includes the boot files, while the second (>1GB) contains the main Linux image. With compression, the combined image can be reduced from several GB (of mostly empty space) to a couple hundred MB.

With a regular Linux desktop computer that has kpartx and mksquashfs installed, you can convert the second partition to SquashFS like this:

$ sudo kpartx -av image_you_want_to_convert.img
add map loop0p1 (252:5): 0 117187 linear /dev/loop0 1
add map loop0p2 (252:6): 0 3493888 linear /dev/loop0 118784
$ sudo mount /dev/mapper/loop0p2 /mnt
$ sudo mksquashfs /mnt converted_image.img -comp lzo -e lib/modules
$ sudo umount /mnt
$ sudo kpartx -d image_you_want_to_convert.img