Re: bin/41072: dd ignores bs= when if= comes from stdin

[SODA Noriyuki <soda%yuruyuru.net@localhost>]

>>>>> On Wed, 25 Mar 2009 02:50:01 +0000 (UTC), perry%piermont.com@localhost 
>>>>> said:

> try
>       something.... | dd of=/dev/somepartition bs=10m progress=1
> and note that you get way too many dots printed. 

That's not a bug, but documented behavior:

     bs=n     Set both input and output block size, superseding
              the ibs and obs operands.  If no conversion values
              other than noerror, notrunc or sync are specified,
              then each input block is copied to the output as
              a single block without any aggregation of short
              blocks.

Please note the following sentence, especially:
        If no conversion values other than noerror, notrunc or sync
        are specified, then each input block is copied to the output
        as a single block without any aggregation of short blocks.
i.e. In this case, dd preserve the return size of the read(2)
system calls at the corresponding write(2) operation.

This behavior is needed to copy a variable-blocksize tape with
preserving each size of tape blocks.
-- 
soda