On Thu, Mar 02, 2017 at 09:06:52PM -0500, fred roller wrote: > On Thu, Mar 2, 2017 at 8:36 PM, Robert Moskowitz <rgm at htt-consult.com> > wrote: > > > dd if=/dev/sdb of=os.img bs=1M count=3210 > > > > I would recommend bs=512 to keep the block sizes the same though not a huge > diff just seems to be happier for some reason and add status=progress if > you would like to monitor how it is doing. Seems the command you have > should work otherwise. The dd blocksize has nothing to do with the disk sector size. the disk sector size is the number of bytes in a minimal read/write operation (because the physical drive can't manipulate anything smaller). the dd blocksize is merely the number of bytes read/written in a single read/write operation. (or not bytes, but K, or Kb, or other depending on the options you use.) It makes sense for the bs option in dd to be a multiple of the actual disk block/sector size, but isn't even required. if you did dd with a block size of, e.g., 27, it would still work, it'd just be stupidly slow. Fred -- ------------------------------------------------------------------------------- Under no circumstances will I ever purchase anything offered to me as the result of an unsolicited e-mail message. Nor will I forward chain letters, petitions, mass mailings, or virus warnings to large numbers of others. This is my contribution to the survival of the online community. --Roger Ebert, December, 1996 ----------------------------- The Boulder Pledge -----------------------------