Tom Stepleton on Thu, 11 Jan 2001 10:47:29 -0500

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[PLUG] Re: copying harddisks

On Wed, 10 Jan 2001, MaD dUCK wrote:
> also sprach gabriel rosenkoetter (on Wed, 10 Jan 2001 02:35:42PM -0500):
> > Should be fine, but I'm not positive dd respects partition maps (and
> > writes them back out properly), so test hdc before you do this:
> well, but wrt /dev/hdb, any partition table, mbr, whatever is just
> bytes. so it shouldn't matter. but no worries, i would have tested hdc
> before.

FWIW, my experience confirms this. I stuck a 100 MB drive from a 486 into
my linux box and dd'd it into a file. Then I put the file onto my old pmac
6100. The 486 was running minix-vmd, and the pmac had a DOS compatibility
card (= amd 486 on a board) inside. The card software read from the file
just fine. This is, as far as I know, the only way to run a non-DOS OS on
a DOS compatibility card.

one worry, however: once, when the sccs had its four old sparcstation
ELCs, I thought I'd save time by only installing linux on one and then
"ghosting" the contents of its drives onto the others with dd. Even though
one or two of the disks for the three other ELCs were identical to the
first one, subsequent attempts to mount the volumes on those drives
failed. The partition tables just weren't right, or so it seemed. Is
this something you need to worry about?

Finally, might it be worthwhile to increase dd's block size with bs= , so
that the task is done in fewer reads and writes?

> may the bluebird of happiness twiddle your bits.


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