Date: Tue, 27 Dec 2016 20:48:27 +0100 From: Polytropon <freebsd@edvax.de> To: galtsev@kicp.uchicago.edu Cc: freebsd-questions@freebsd.org Subject: Re: 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 Message-ID: <20161227204827.be793f5d.freebsd@edvax.de> In-Reply-To: <25327.128.135.52.6.1482867129.squirrel@cosmo.uchicago.edu> References: <1482841113.1239624.830388025.494E966F@webmail.messagingengine.com> <20161227190844.fdc2390f.freebsd@edvax.de> <25327.128.135.52.6.1482867129.squirrel@cosmo.uchicago.edu>
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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, ...
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