Hi Terry, > So (at long last) here is the question. Why does PartImage need a > bigger partition to store its image into than the one it came from, > even though I am using compression?
Compression, as I'm sure you know, can make things larger sometimes. Otherwise I'd just compress the compressed output. And then compress that some more. And... Profit! I'd expect a recovery partition would already have compressed contents with high entropy so your compression is probably just burning CPU time and coming up with a slightly larger result; "Here's a large number of bytes that aren't compressed" followed by the original data. The exception to that may be the filesystem's data, but it's probably a small amount of the partition. Also, it sounds like you've made a filesystem in the destination partition and want the copy to appear there as a file or two. That filesystem will use up some of the partition's space for its own data, e.g. what you see with `ls -l', so to image a 1GiB partition to a file in a filesystem needs at least 1GiB of free space in that filesystem, as reported by `df'. > Secondary question; is it creating temporary files in the target > directory? If so, how much bigger does the target partition need to > be? You'd hope not, wouldn't you, but it may be. Let me get this right, you want to an image of a partition split across two files so each can be burned to a DVD? Ensure the source partition is unmounted, we don't want it changing during the copy, then src=/dev/sda1 n=7000 cd /destination/partition/with/space/for/images sudo dd if=$src of=win7.1_of_2.img bs=1M count=$n sudo dd if=$src of=win7.2_of_2.img bs=1M skip=$n The block size, `bs', is 1MiB, i.e. 2^20 not 10^6; that's how much dd will read(2) and write(2) at a time. `count' is how many of those blocks to copy; you may want to change n from 7000 so you're happy both parts will fit on a DVD each. Once you've got the two image files on disk you can see if they match the source. Either sudo sha1sum $src cat win7.?_of_2.img | sha1sum to see both give the same digest or sudo cmp $src <(cat win7.?_of_2.img) The former will allow the hard disk to read all the data sequentially, the latter will have it keep seeking between the two partitions, and seeks and settle time are slow. You can do similar checks once the files are on DVDs. dd can be used to copy back the image files into a partition. One word of caution, is everything need for recovery definitely in the one partition? No hidden bits around the disk anywhere? That would catch out PartedMagic as well, of course. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday 2012-03-06 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue