DAT2330 - Harold Smith Class - Wed Feb  3, 2000

Today: MVS JCL Example 2 (with attached homework)

IDCAMS

- what are control statements?
  - tell the IDCAMS program what to do
  - chooses among many possible options
	- similar to command line arguments and flags
	- IDCAMS could take parameters; but, there are too many
	- instead, read a dataset containing the options
	  - dataset comes on SYSIN; usually instream data
	- may have 10-15 lines of control statements

- what DDnames are used in the copy step?
  - you get to pick the names
	- DDnames given in the control statements

- what DDname for the instream COBOL source program?
  - not specified - have to guess
	- we will need to set MSGLEVEL to get max info from run
	- try COMP.SYSIN ?
	- DDname "SYSIN" chosen by the author of the COBOL compiler program
	- DDname "COMP" chosen by PROC author

- what part of the proc wants TAPEDATA?
  - not compiler (review: what does compiler do)
	- not linker (review: what does linker do)

Refer to new checklist - new parameters on JOB and DD

Coding JCL
- fixed width font, 12 point, with ruler bar (WordPad)

CLASS 
- not a print queue!
- Classes change from shop to shop
- check list of classes; choose "dog"

MSGCLASS
- specifies which spool queue to use for JES messages
- typically sends output to printer
- may need to spool to TSO queue
- choose letter closest to A

Note that you can't "watch the program run"
- batch programming only

MSGLEVEL
- level of detail coming from JES (not from any programs)
- (1,1) is maximum (positional parameters)
- (,1) means use default for 1sp parameter

One missing comma throws the job out
- remember the trailing commas

Continuation lines: start with //, indent to 16 or less.
  - don't indent past column 16
  - some posted examples violate this so that they read
    more clearly to the novice eye - don't code this way!

PRTY
- choose among various class A jobs
- not strictly FIFO
- Windows: FISH (first in still here)
- depends on MVS version, e.g. 0 to 15, eith 15 highest
- some account codes cannot use some priorities

Example #2
----------

//coboltst job  1234,'my name',class=D,
//              msgclass=D,MSGLEVEL=(1,1),
//              PRTY=15
//         exec pgm=idcams

Order of JCL statements
- professors want instream DD statements last
- put biggest instream last

DD statements
- sysout is only for print output
DCB describes the dataset
- defaults apply where program doesn't specify
- we concentrate on 4 parameters
- look up each of these new parameters in the book
- DSORG - tapes are only sequential (physical sequential)
  - IDCAMS defaults to PS
- professor requires this order to these four parameters!
  - logical order; but, MVS doesn't care
- tape gap takes sizeable space; don't want a lot of them
- want 
- instream data is always 80 characters (LRECL)
- IDCAMS has output specs equal to input specs
- why not use huge block sizes?
  - uses up too much memory
	- pick a 4k block size; but, must be multiple of 80
	  - less than or equal to 4k fits in paging buffer nicely
- don't need LABEL if using standard IBM labels
- UNIT: up to now, datasets were catalogued
  - system knew which unit they were on based on catalogue
	- 3480 is a possible tape unit; but, it's not general
	- use group names instead
	  - chosen by system programmers at sysgen time
		- consult shop for names
		- group SCRATCH is appropriate for a temp tape

//outdd    dd dsn=testdata,disp=(new,pass),
//            dcb=(dsorg=PS,lrecl=80,
//            blksize=4080,recfm=FB),unit=SCRATCH
//sysprint dd sysout=D

- rules for IDCAMS are not JES rules
- TYPERUN=SCAN will not find these errors

//sysin    dd *
  repro infile(indd) outfile(outdd)
/*
//indd     dd *
...many test records go here...
...syntax of these lines dictated by input requirements of
...cobol program that will be reading them...
/*

- must order DD statements for a PROCL in same order as PROC

//clg      exec proc=cobolclg
//comp.sysin DD *
...cobol program source goes here...
/*

- look inside cobol program to see what the author decided for
  the output data format
- cobol program specifies LRECL, no need for us
- block contains 0 records ==> let JCL set the size
  - don't want to fix it in the program
- no need for vol or ser since we use *any* tape
- passed tapes don't need DCB
  - only need DSN and DISP
- uncatalogued datasets need to be found
  - never need DCB for input dataset (it's in the label)
- ANSI - american national standards institute
  - non-IBM, used to share tapes with non-IBM
	- LABEL takes positional parameters!
	- cannot reorder them, need leading commas
	- need second parameter
- VOL takes keyword subparameters - can reorder them

//go.mstout   DD dsn=tstout,disp=(new,pass),
//               dcb=(blksize=4000,recfm=fb),
//               unit=scratch
//go.prtop    DD sysout=B
//go.tapedata DD dsn=testdata,disp=(old,delete)
//go.lstin    DD dsn=prodlist,disp=(old,keep),
//               label=(,AL),unit=syssq,vol=ser=123456

Do the homework: MVS JCL Example 2 Homework
- we will review it next class