On 28 Mar 2013, at 5:24 AM, <[email protected]
<mailto:[email protected]>>
<[email protected]
<mailto:[email protected]>> wrote:
Google 'AA-JS16A-TC' for some Files-11 format information; I'd
have to think a bit on the DOS-11 format.
RSX/VMS Files-11 tapes are ANSI labeled tapes. I know OpenVMS also
used HDR3/4 labels for RMS information. There was a MOUNT option to
suppress writing those labels.
I wrote an RSX/VMS program that will scan an unknown tape and decode
it for you. (If anyone wants it, let me know where I should upload
it.) The DOS format decoder looks for a 14 byte (physical) record at
the start of the file. It is decoded by the following code:
C
C... DEC DOS labels
C
Call R50ASC ( 6, buffer( 1), ascbuf( 1) )
Call R50ASC ( 3, buffer(13), ascbuf( 7) )
ascbuf(10) = '.'
Call R50ASC ( 3, buffer( 5), ascbuf(11) )
ltemp(1) = buffer(7)
ltemp(2) = 0
mem = itemp
ltemp(1) = buffer(8)
grp = itemp
ltemp(1) = buffer(11)
ltemp(2) = buffer(12)
jday = MOD(itemp,1000)
year = itemp/1000 + 70
Call JDCONV ( jday, mon, day, year )
ltemp(1) = buffer( 9)
ltemp(2) = buffer(10)
Write (STDOUT,619) ifile, grp, mem, ascbuf, day, month(mon),
1 year, itemp
619 Format (//' File ', I4, ':', T34, '"', '[', O3.3, ',', O3.3, ']',
1 13A1, 2X, I2, '-', A, '-', I2.2, ' <', O3.3, '>', '"')
The DOS label contents are:
Words 1-2 RAD50 characters 1-6 of the file name part (before the
implied period)
Word 3 RAD50 characters 1-3 of the file type (after the implied period)
Word 4 Octal File owner's User Identification Code (group code in
high-order byte, member code in low-order byte)
Word 5 Binary File creation date ( 1000 * ( year - 1970 ) + Julian day )
Word 6 Octal File protection (low-order to high-order RWED bits: read,
write, extend, delete; grouped low-order to high-order for system,
owner, group, world)
Word 7 RAD50 characters 7-9 of the file name part (before the implied
period)
The references I used to write the program (back in the 1980's) are
below. Which reference had the DOS label format I don't remember (if
any of them did).
6 References
[1] American National Standards Institute, 1978, Magnetic Tape Labels
and File Structure for Information Interchange (ANSI X3.27-1978).
[2] Digital Equipment Corp., 1985, RSX-11M/M-Plus MCR Operations
Manual (Order no. AA-FD10A-TC).
[3] Digital Equipment Corp., 1985, RSX-11M-Plus Command Language
Manual (Order no. AA-FD04A-TC).
[4] Digital Equipment Corp., 1985, RSX-11M/M-Plus and Micro/RSX I/O
Operations Reference Manual (Order no. AA-FD14A-TC).
[5] Digital Equipment Corp., 1985, RSX-11M/M-Plus I/O Drivers
Reference Manual (Order no. AA-FD09A-TC).
[6] Digital Equipment Corp., 1984, VAX/VMS Command Definition Utility
Reference Manual (Order no. AA-Z408A-TE).
[7] Digital Equipment Corp., 1986, VAX/VMS DCL Dictionary (Order no.
AA-Z200C-TE).
[8] Digital Equipment Corp., 1984, VAX/VMS Mount Utility Reference
Manual (Order no. AA-Z424C-TE).
[9] Digital Equipment Corp., 1986, Guide to VAX/VMS Disk and Magnetic
Tape Operations (Order no. AI-Y506B-TE).
[10] Digital Equipment Corp., 1986, VAX/VMS I/O User's Reference
Manual: Part I (Order no. AA-Z600C-TE).
[11] International Business Machines Corp., 1978, OS/VS Tape Labels
(Order No. GC26-3795-1).
Larry Baker
US Geological Survey
650-329-5608
[email protected] <mailto:[email protected]>
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