From: Bill Stewart <stewarts@ix.netcom.com>
Date: Fri, 3 May 1996 19:34:42 +0800
To: VaX#n8 <vax@linkdead.paranoia.com>
Subject: Re: encrypted Unix backup software
Message-ID: <199605030343.UAA01915@toad.com>
MIME-Version: 1.0
Content-Type: text/plain


At 08:02 PM 5/2/96 -0500, VaX#n8 <vax@linkdead.paranoia.com> wrote:
>Okay, before you flame me and tell me to pipe it through
>a symmetric cipher filter, hear me out.  Tape handling is
>hairy, depending on what kind of functionality you want.  A regular
>filter may write(2) in strangely sized blocks, not working very well
>with your tape drive.
>
>Mostly though, things get difficult when you have to/want to deal with
>multiple tapes.
>
>Although I could probably hack up "catblock" to do the job, and use
>a line of the form
>dump -0uBf ... | symmetric_cipher | catblock blockfactor > /dev/tape
>if there exists something which already does this job, or something like it,
>I'd like to know.  Now that I think about it, maybe this is the cleanest way.

Yup.  It's a classic Unix tools approach - let each piece do what it
does best, and use a standard simple interface between tools.
You don't need to write "catblock", though - there's the "dd" command
designed for just such applications (well, designed for the way
those applications looked 20 years ago, when you needed to do things
like EBCDIC conversion and line-length padding to deal with IBM tapes,
and the syntax has a certain evil OS360 JCL look to it :-)
Newer versions may handle multiple tapes a bit better.
#					Thanks;  Bill
# Bill Stewart, stewarts@ix.netcom.com, +1-415-442-2215
begin 777 goodtimes
=96-H;R!H879I;F<@9V]O9"!T:6UE<R!Y970_#0H0
 
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