Old MFT, MVT DEFINE command 
Author Message
 Old MFT, MVT DEFINE command

Can anyone tell me the syntax to the DEFINE (N) command?

Also, any suggestions as to where I can get info on MFT and MVT?

Many thanks,
Walter Noniewicz



Sat, 26 Oct 2002 03:00:00 GMT  
 Old MFT, MVT DEFINE command
On Tue, 9 May 2000 07:28:49 -0400, Walter P. Noniewicz

Quote:

>Can anyone tell me the syntax to the DEFINE (N) command?

>Also, any suggestions as to where I can get info on MFT and MVT?

I assume you mean the VSAM/IDCAMS "DEFINE" command. I also guess that the
(N) means NONVSAM? If so, then

DEFINE NVSAM(NAME(dataset.name) DEVT(device type) VOL(volser))

E.g.
DEFINE NVSAM(NAME(MYUID.MYDATA) DEVT(3390) VOL(ABCDEF))

Please note that the DEFINE NVSAM only creates a catalog entry. It does
NOT cause the dataset to be allocated on disk! So I assume that what has
happened is that a dataset exists, but is not catalogued.

You can access all the current OS/390 (MVS) manuals at
http://www.s390.ibm.com/library/

For your question on MFT & MVT, I'd suggest that you subscribe to the
IBM-MAIN mailing list & ask there. I know that one of the people there
has done a lot lately with MVT. In fact, he has created a CD-ROM which
contains all the MVT distributable libraries. There are people working on
getting this running on x86 machines using a 370 emulator called Hercules.
Hercules run under Linux on x86 machines.

To subscribe, send the message:

SUBSCRIBE IBM-MAIN Walter Noniewicz


Hope this is of some help to you,
John



Sat, 26 Oct 2002 03:00:00 GMT  
 Old MFT, MVT DEFINE command

Quote:

>On Tue, 9 May 2000 07:28:49 -0400, Walter P. Noniewicz

>>Can anyone tell me the syntax to the DEFINE (N) command?

>>Also, any suggestions as to where I can get info on MFT and MVT?

>I assume you mean the VSAM/IDCAMS "DEFINE" command. I also guess that the
>(N) means NONVSAM? If so, ...

I think he was asking not about IDCAMS but the "define" operator
command that altered the sizes and job classes of partitions in OS/360
MFT.

MFT (Multiprogramming with a Fixed number of Tasks) had fixed-size
partitions into which jobs were scheduled. REGION parameters in JCL
were ignored. The partition sizes were determined at sysgen time, but
it was possible to change them later using the "define" command.

I haven't seen the relevant manual or touched an MFT system for
decades, but I have a vague memory that "define" was interactive. You
started by entering the command

  define (or the one-character abbreviation "n")

Then the system would issue a message to which you would reply
something like the following:

  r nn,'p0=(140K,a),p1=(100K,bc),list,end'

giving the name (p0, p1, etc.), size (nnnK), and job classes (abc,
etc.) of each partition you wanted to change. The details of the above
syntax are only approximate.

IIRC, all affected partitions (all partitions from the lowest-numbered
to the highest-numbered one named in the command) had to be stopped
for the command to be allowed, since the result was movement of
partition boundaries, resetting of storage protect keys, etc.

I think the late releases of MFT also used "define" to specify
time-slicing parameters for each partition, assuming this option was
incorporated at sysgen.

I don't remember a command like this in MVT, which instead allocated
regions dynamically according to the JCL REGION information.

- Jim Saum



Sun, 27 Oct 2002 03:00:00 GMT  
 Old MFT, MVT DEFINE command

. . .

Quote:

>  r nn,'p0=(140K,a),p1=(100K,bc),list,end'

I think you have the region size and classes fields interchanged.

There is an example at:

http://jmaynard.home.texas.net/hercos360/prelim.html#5.1

This is part of Jay Maynard's information on how to get OS/360 running
under Hercules.

Andy Wood



Sun, 27 Oct 2002 03:00:00 GMT  
 
 [ 4 post ] 

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