Message-Id:	<s458832e.026@calderauk.com>
Date:	Thu, 30 Oct 1997 12:52:38 +0000
From:	Matthias Paul <MPaul AT calderauk DOT com>
To:	opendos AT delorie DOT com, opendos-support AT delorie DOT com,
	paul-ma AT reze-1 DOT rz DOT rwth-aachen DOT de
Subject:	Re: ?
Mime-Version:	1.0

On 97/10/30 11:43:22 someone wrote:

>I found that the xcopy.exe command in opendos 7.02
>is completely unreliable.
>I used the command:
>xcopy c:\*.* e: /s /a /e
>to copy all files in all subdirectories from the hard drive.
>xcopy failed to do this.  

Of course, actually it must fail as your harddisk does contain more
data than suitable for *one* Bernoulli cardridges... If the target medium
gets full, XCOPY will display an error message. In this situation you
*must not* exchange the medium, and press Retry, but you *have to*
press Abort. 
Otherwise some of the directory info might not have been flushed out
to the first medium, and the second medium might get mixed up by 
invalid references to it. OpenDOS tries its best to detect this situation 
(actually, it is more likely to ruin your disk with MS-DOS then with OpenDOS
in this scenario), but the actual behaviour depends on your drivers loaded, especially when using FASTOPEN or NWCACHE (though both are
very reliable when been used with care).

If you have pressed Abort, and then restart XCOPY on the new medium,
XCOPY will restart the procedure.

> However there were not enough of them to have used 12
>20 meg bernoulli cartridges from a 212 mb hard drive.
>What I found when checking cartridges was 12 exact copies of one >cartridge.
See above.

>I'm not even going to try the backup utility, I'm afraid what will happen
>if restore screws up.  
I have used BACKUP/RESTORE in ancient times, and they did work 
very reliable. Actually, BACKUP/RESTORE are exactly what you need
if you plan to backup a hugher medium on multiple smaller ones (but 
you should better switch to other backup solutions like streamers if you 
need  to backup more than 200-300 MB). For your purpose a QIC-80+
floppy port streamer might be a good solution, or maybe a ZIP-100 drive.

Also you could use PKZIP, ARJ, RAR or the like to better compress
your data when backing up. These utilities have options to create
volume files of exact the size of your cardridges, and therefore allow
for easy backups on multiple media. For your purpose, RAR might
be the best solution, since it has a build-in  solid compression mode 
for increased compression, and optionally has a quite intuitive interactive
menu mode (similar to NC design).

Hope this could help a little,

 Matthias




------------------------------------------------------------
Matthias Paul
eMail: <Matthias DOT Paul AT post DOT rwth-aachen DOT de>
Web: http://www.rhrz.uni-bonn.de/~uzs180/mpdokeng.html

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