On 04/03/11 05:02, Станислав wrote: > [dd] bs=blocksize doesn't work as expected, for example: > tar -c /somedir | dd bs=256K of=/dev/nst0 > In this example backup record will be recorded to a tape with block size = > 10K instead of 256K because 10K is default for tar. > There is workaround: > tar -c /somedir | dd ibs=256K obs=256K of=/dev/nst0 > If we set block size for input and output separatly - it works as expected.
This operation is expected and dictated by POSIX. It is surprising though, and I tried to clarify it in the docs: http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=d5ab0599 Note also that we're currently considering warning that iflag=fullblock should be used, but only currently in the case were a count is specified, as then you get the wrong amount of data as well as the wrong sized writes. http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7362 cheers, Pádraig.
