Fwd: dd -bs=BYTES read and write up to BYTES at a time system -invalid number 1m #### dd if=FreeBSD-11-RELEASE-amd64-memstick.img of=/dev/sdb1 bs=1M conv=sync

Polytropon freebsd at edvax.de
Tue Dec 27 19:48:38 UTC 2016


On Tue, 27 Dec 2016 13:32:09 -0600 (CST), Valeri Galtsev wrote:
> The vital where you _should_ use "bs=2048" is when you dump a track of
> CD/DVD.

Except when you are dealing with _audio_ CDs, then you
need bs=2352 for raw data. :-)



> (especially when doing recovery of badly damaged CD, then few
> extra options are a must to make exact sector for sector copy or bit for
> bit, even though in some unreadable areas they are are filled with
> zeroes).

Tools like dd_rescue can dynamically adjust the block size
and re-read with decreasing sizes (and even repeat several
times) in case of read errors.




-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...


More information about the freebsd-questions mailing list