From: ichudov@Algebra.COM (Igor Chudov @ home)
Date: Wed, 11 Jun 1997 10:49:51 +0800
To: dlv@bwalk.dm.com (Dr.Dimitri Vulis KOTM)
Subject: Re: BAD ADVICE WARNING from Kent: Access to Storage and Communication
In-Reply-To: <95X48D67w165w@bwalk.dm.com>
Message-ID: <199706110235.VAA04670@manifold.algebra.com>
MIME-Version: 1.0
Content-Type: text



Dr.Dimitri Vulis KOTM wrote:
> Ray Arachelian <sunder@brainlink.com> writes:
> > Passphrases can be memorized.  4mm DAT tapes hold several gigs and are
> > tiny.  Ever see one?  Fits in your pocket.  It's smaller that an audio
> > cassette. Fairly easy to guard, but, if your data is backed up in
> > encrypted form (cyphertext), and not clear text, you don't even need to
> > bother protecting the tape. (That is unless your backup software uses a
> > weak cypher as most tend to do.)  [FYI: Your knowledge of tape
> > technologies is severly lacking. 4mm tapes hold 2-4Gb.  Exabytes 5Gb-10Gb.
> > Mamouth Exabytes (same size as 8mm camcorder video tapes, smaller than
> > audio cassettes) hold as much as 40Gb in a very small form factor.]
> 
> I'm actually thinking of getting a pair of 4mm tape drives to replace
> my existing backup system (very old drives that use DC 600As; only
> .25GB / drive, pretty slow, no NT drivers; time to upgrade)
> 
> I wonder: if the data is well-encrypted, wouldn't it make the compression
> pretty ineffective?

You can compress before the encryption (if the encryption algorithm
does not do compression).

tar cvfz - /directory | Encrypt > /dev/ftape

or something like that.

Another thing to worry about is being able to at least partially restore
data if one or several blocks get corrupted.

	- Igor.