File Recovery.doc						7 May 1991

	Program Recovery.c is a quick attempt to recover files from
Novell NetWare NBACKUP archive files. Recovery does this by scanning
the files looking for signatures to open and close specific files, and
it tries valiantly to ignore any errors in the archive files.
	The actual file size from NBACKUP is used to truncate file length,
but corrupted archives may result in shorter files. So far I have not
found the file time and date stamp. Bindery information is discarded.
	Recovery asks for the name of the first archive file to process
and the extension (three hexadecimal characters but you state them as
just three characters) of the last archive file to consider. Recovery
will process archive files sequentially, even if archive files are missing
in the middle. The BACK$LOG and BACK$ERR files are not used. The output
directory may be specified and it becomes the "root" as seen by the Novell
directory structure in the archive files.

	A running description is presented on the screen. It may be
redirected to a file or printer via standard DOS syntax.

	The reason for this program's existance is simple: NBACKUP would
not restore two backup sessions holding an entire server's disk during
NW upgrading. The reason seems to be NBACKUP overwrote and corrupted it's
own archives. Next time I'll use my own rule of backing up using two
completely different methods.

	Here are three simple goals for any serious archiving program:
	1. The program will do a round trip, end to end, validity check
using the archiver in one direction and the restore program in the other,
all without writing to the original sources. This costs time, but look
what one stands to lose otherwise. Single ended checks are insufficient.
	2. The restore program will extract all available information
regardless of corrupted and/or missing archive files. It will never give
up because of such factors.
	3. The data structures of archive files will be published so that
hand tooled recovery may be attempted in vital cases.

	I know of no PC related archiving program meeting these goals today.

	If you find this program useful then send me your thanks and keep
the money. Recovery is copyrighted but may be distributed only at no
profit. Corrections and enhancements are more than welcomed.

	Joe R. Doupnik
	EE Dept and CASS
	Utah State University
	Logan, Utah 84322
	jrd@cc.usu.edu, jrd@usu.Bitnet
	(801) 750-2982 voice
	(801) 750-2992 fax