FIXHEADER			February 1983

	VICKI W. WOOLF 
	PROGRAM OF COMPUTER GRAPHICS - CORNELL UNIVERSITY
	120 RAND HALL   ITHACA    NEW YORK   14853  (607) 257-6444

	Modified by
	LES TABATA          (415) 486-5766
	COMPUTER SCIENCE & MATHEMATICS
	BLDG 50B RM 3238
	LAWRENCE BERKELEY LABORATORY
	BERKELEY, CA 94720
	
	The FIXHEADER program can be used to display the virtual or
	logical data blocks or the file header blocks.  It can also
	be used to alter the EOF marker of a file.
	Program accepts either a filename,logical name or file id (octal)
	as input.  The following general information is displayed.
		file name
		complete file path name
		file id and sequence numbers
		number of used and allocated blocks.
		first free byte number in last block used.
		owner uic.
		virtual to logical block mapping information.
	The user has the following options:
		G - Display general information.
		? - Display list of commands.
		M - Display list of map pointers.
		V - Display data block specified by virtual block number.
		L - Display data block specified by logical block number.
		H - Display file header block specified by block number.
		I - Invert file extent pointers.
		F - Find file id by LBN.
		C - Display and change eof marker.
		W - Write changes back to disk.
		N - Enter a new file.
		E - Exit.

	The orginal purpose of the utility was to patch 0./non0. files.

	To build:
		Use FIXHEADER.COM
		      or
		$FOR FIXHEADER
		$MAC/OBJ=FIXHEADM FIXHEADER
		$LINK FIXHEADER,FIXHEADM

	The file SSDEF.FOR should be placed in the SYS$LIBRARY directory.
	It is a Fortran include file containing the system service error
	code definitions.

	This version includes the following additions
		1. The General option now displays the full file
		   path name, e.g. 
			dra0:[000000.top.sub.sub]filename.ext;1
		2. System service errors will now display the error code
		   mnemonic in addition to the hex error code, e.g.
			SS$_PARITY  =  '01F4'X
		3. The Find option works with DB and DR type disks.  For
		   other disk types, appropriate cylinder/track/sector
		   information may be entered online.