On Oct 8, 2012, at 3:21 AM, Wojciech Puchar wrote:

>> Not necessarily.  If I understand correctly what Tim means, he's talking
>> about an in-memory compression of several blocks by several separate
>> threads, and then - after all the threads have compressed their
> 
> but gzip format is single stream. dictionary IMHO is not reset every X 
> kilobytes.
> 
> parallel gzip is possible but not with same data format.

Yes, it is.

The following creates a compressed file that
is completely compatible with the standard
gzip/gunzip tools:

   * Break file into blocks
   * Compress each block into a gzip file (with gzip header and trailer 
information)
   * Concatenate the result.

This can be correctly decoded by gunzip.

In theory, you get slightly worse compression.  In practice, if your blocks are 
reasonably large (a megabyte or so each), the difference is negligible.

Tim

_______________________________________________
freebsd-hackers@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"

Reply via email to