OT: paging MAC expert(s) --- What's a Performa?

From: Christopher Smith <csmith_at_amdocs.com>
Date: Mon Nov 19 17:00:39 2001

> -----Original Message-----
> From: Richard Erlacher [mailto:edick_at_idcomm.com]

> If your recorded "backup" is a bit-for-bit image of the disk contents,
> transferred to and from tape, there's no interpretation of
> the contents into
> files that can take place, is there?

That's an interesting way to phrase this particular question, since the
contents are already in the form of "files" -- that is, if you ask the set
of drivers that got them to the disk in the first place. :)

I believe it's possible (though it would be slow) to interpret a bit-for-bit
image directly on a tape and extract any given file, along with attributes,
etc. In fact, any operation that would be possible on a disk, in this case,
could be handled on a tape. The clincher is that it would involve a lot of
seek/rewind/seek/etc/etc..

The underlying O/S need not even know the difference between the disk and
tape, except to know that the tape is removable (...that's not absolutely
required), and perhaps that it's incredibly slow.

The worst that would be required is a device abstraction layer or the like.
You could write one yourself which would make the tape device "look" like a
disk device, for systems which don't have such a thing, and that would be
enough.

How would you like to be able to mount your backup tape, and use a
file-manager on it? ;)

> The Microsoft Backup that came with DOS, (a) never really was
> a backup, but,
> rather, was just a copy, and (b) never worked together with
> its "restore"
> function. Under DOS, copies were adequate, since the context
> didn't matter.

If you mean that it didn't store attributes, or that sort of thing, you may
be right (never paid attention.) On the other hand, you're also right to
say that it wouldn't particularly matter under MS-DOS.

Regards,

Chris


Christopher Smith, Perl Developer
Amdocs - Champaign, IL

/usr/bin/perl -e '
print((~"\x95\xc4\xe3"^"Just Another Perl Hacker.")."\x08!\n");
'
 
Received on Mon Nov 19 2001 - 17:00:39 GMT