On Thu, Jan 21, 2010 at 12:38:56AM +0100, Ragnar Sundblad wrote: > On 21 jan 2010, at 00.20, Al Hopper wrote: > > I remember for about 5 years ago (before LT0-4 days) that streaming > > tape drives would go to great lengths to ensure that the drive kept > > streaming - because it took so much time to stop, backup and stream > > again. And one way the drive firmware accomplished that was to write > > blocks of zeros when there was no data available.
> I haven't seen drives that fill out with zeros. Sounds like an ugly > solution, but maybe it could be useful in some strange case. It was closer to 15 years ago than 5, but this may be a reference to the first release of the DLT 7000. That version came out with only 4MB as a RAM buffer, which is insufficient to buffer at speed during a stop/start cycle. It didn't write zeros, but it would disable the on-drive compression to try to keep the speed of bits being written to tape up. So the effect was similar in that the capacity of the media was reduced. The later versions had 8MB buffers and that behavior was removed. -- Darren _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
