zip (was: Re: Disk archival techniques)

[John A. Dundas III]

Al,

At 10:27 AM -0700 5/19/05, Al Kossow wrote:
>Do you still have this (I assume it's different from the various C 
>versions of "VMSBACKUP"
>floating around)

Yes, I think I could probably find it or some generation of it with 
some work.  And yes, it was different from VMSBACKUP that made the 
rounds.  I never published that bit of work.

>That program does not do a very good job of recovering from archive errors.

Don't know how that program works.  As I remember, you need to keep 
/GROUP_SIZE buffers laying around at all times in order to perform 
the verification and error correction step.

>There appears to be very little written down about the variations in 
>the VMS Backup
>format as well.

Quite true, but...

At 6:38 PM +0100 5/19/05, Antonio Carlini wrote:
>I think the last time the format was documented was in
>an appendix to one of the VAX/VMS V3 manuals. Not much
>has (apparently) changed since then.
>
>You can get backup to spit out a fair amount of info
>by adding /ANALYZE to a BACKUP/LIST command.
>
>And the source listings are available.

Indeed that is the way I discovered things.  At the time I had a 
fiche reader on my desk at work (as well as a machine readable 
version of the V3 listings) and used /ANALYZE liberally.

I still have some of the paper documents from V3 that specified the 
format.  Would you like those scanned?

Just out of curiosity, is this program something you could use Al?

John