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Conference turris::languages

Title:	Languages
Notice:	Speaking In Tongues
Moderator:	TLE::TOKLAS::FELDMAN

Created:	Sat Jan 25 1986
Last Modified:	Wed May 21 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	394
Total number of notes:	2683

181.0. "Fortran & Magtape Blocking" by MAVSN1::PIERSON (Don P. DTN 337-4003) Tue Apr 26 1988 21:41

    
    I've got a question about the interplay of Fortran and VMS in the
    handling of magtapes. Assuming latest versions of all..
    (I hope that this is in the right place).
    
    What I'm describing here is witnessed behavior, and am interested
    in knowing into which category it falls (a - BUG; b- Feature; or
    c- Undocumented behavior).
    
    Without further ado...
    
    In cases where the record length and block size of the fortran
    OPEN and the DCL Mount command exactly match, there is no problem
    and all works as expected. Naturally..
    
    However, let the Fortran OPEN parameters be smaller than (either
    record length or blocksize or both) those in the mount command,
    what u get is an unblocked tape (ie. 1 record/block).
    
    The reason for wanting this to work is based on a need to place
    multiple files of different record/block size on a tape without
    having to do DISMOUNT/Nounloads; re-MOUNT and skip passed the
    number of file marks for each file from the 2nd on...
    
    
    Any insight (even what manual I missed the reference in) would be
    greatly appreciated.
    
    Thanks.
    /Don

T.R	Title	User	Personal Name	Date	Lines
181.1	Try TLE::FORTRAN	MOIRA::FAIMAN	Ontology Recapitulates Philology	`Wed Apr 27 1988 09:12`	4
	You are likely to get a quicker answer in TLE::FORTRAN (press SELECT or KP7 to add it to your notebook). -Neil
181.2		CHESS::KAIKOW		`Sat Apr 30 1988 16:22`	15
	re: 181.0 I will assume that we are talking ONLY about the input case. 1. It does not matter, at least to RMS, what you put in the FORTRAN OPEN. The HDR2 label for each file has the relevant information. 2. If HDR2 labels are present, you need not specify any record or block size in MOUNT, unless the blocksize is greater than 8192. 3. If a file does not have a HDR2 label then you will have to use dismount and mount system services to read each such file by specifying the record length appropriate to each file in each mount. This ONLY applies if the file has fixed length records, otherwise a HDR2 label MUST be present.
181.3	Tape generation is the name of THIS game...	MAVSN1::PIERSON	Don P. DTN 337-4003	`Sun May 01 1988 02:15`	12
	Well, Unfortunately I'm concerned about the OUTPUT case. As it stands right now, the only solution I see to the 'problem' is a dismount/remount and skip-to-file whenever the characteristics change. Any other ideas?? Thanks for the help so far! /don
181.4		CHESS::KAIKOW		`Sun May 08 1988 09:12`	32
	re: 181.3 From: CHESS::KAIKOW "Howard Kaikow ZKO3-4/Z09 381-1122" 6-MAY-1988 00:45 To: MAVSN1::PIERSON,KAIKOW Subj: RE: Notefile LANGUAGES Note 181.2 As you may note the time of this message, I will be brief as I have been travewlling all day and night. If you are generating the tapes on a VAX/VMS system, then you should not specify anything in MOUNT for /RECORDSIZE and need specify /BLOCKSIZE ONLY if you need a BLOCK LENGTH greater than 8192. There is NO reason to MOUNT/DISMOUNT the tapes for different record lengths in the FORTRAN program, if you are WRITing the files with RMS. If the above doesn't solve your problem, then either I'm missing something or the description of your problem is incomplete. ***************************************************** From: MAVSN1::PIERSON 1-MAY-1988 01:37 To: 19700::KAIKOW Subj: RE: Notefile LANGUAGES Note 181.2 I appreciate your mailing the response to me. Unfortunately, what I'm dealing with here is the GENERATION of the tapes. I sincerely hope that there is a way around dismount/re-mount scenarios (w/ file skips) in order to put multiple record/blocksizes on the same physical tape. Any ideas??