Nina Pham wrote:
> The tape can hold 20 G, but tar fail when it?s been at 16 G.
Um.
Many years ago now, the first tape drives came out that could compress
backups as they were written to tape (and the compression was done by
the drive, not the host processor).
Since then, tapes and tape drives have had two figures quoted for
capacity: their "native", physical capacity, and their "compressed"
capacity, which is almost always given as twice the native capacity.
So a tape might really, physically hold 4 GB, but be sold as having a
"compressed" capacity of 8GB.
(That's if you're lucky. Salespeople will be salespeople, and will quote
the largest number they think they can.)
Now, that 50% compression is the sort of wild guess that gives wild
guesses a bad name. Many databases will compress like an empty can under
a Challenger tank, and you can easily fit 16 GB on that tape. On the
other hand, you aren't going to squeeze .ogg or .tar.bz2 files any
further, and you'll only fit 4 GB on there.
So which of those figures is that 20 GB you quoted? If it's the
compressed figure: yes, that's perfectly normal.
James.
--
E-mail address: james | "!" sez I. And "?". After a few speechless seconds
@westexe.demon.co.uk | I come out with "%^&*". Unless I come up with
| something plausible soon I'm going to run out of
| special characters. -- Ben at lspace.org
