VAX/VMS Magnetic Tape Labels

[utzoo!decvax!ucbvax!unix-wizards]

>From menlo70!sytek!rob at Berkeley Wed Oct 28 14:36:16 1981
    Another source to consider for VAX/VMS or any other DEC  Magnetic  Tape
Label is the following:

	"DEC Magnetic Tape Labels and File Structure Standard"
	By, Lois Framptom, July, 1978, #005-003-187-11.

I am not sure of DEC  availability.  This  document  defines  4  levels  of
magnetic  tape  label  formats, record formats and tape-mark relationships.
It seems that DEC wanted to conform (or try) to ANSI  X3.27-1977,  Magnetic
Tape Labels and File Structure for Information Interchange.

    This document attempts to set the  DEC  standard  for  RSX/IAS,  RT-11,
RSTS/E,  VMS/RMS, TOPS-10 and TOPS-20 DEC systems.  I have only worked with
RSX-11/M (PIP tapes) and VMS (Ver. 1.6, 2.0  &  2.1)  RMS  tapes.  The  RSX
tapes  follow  the  standard and are not to hard to read.  VMS tapes on the
other hand are not even fully interchangeable between the  above  versions.
This  stems  from  the  their  handling  of  the HDR2 record CP16-36 System
dependent file attributes field.  They went from binary encoding  to  ASCII
one  time  and  another  they added a HDR3 record (surprise).  The nastiest
field to figure out is the number of characters in the "fixed area"  within
fixed-length  records  format.  Some files will it have and others will not
even in the same VOL1 grouping.

    Rob Cardoza (ucbvax!menlo70!sytek!rob)