IBM OS/390 User Manual
Unlike VSE, the operator does not manipulate elements within a job stream, nor
is he given the opportunity to correct JCL errors. The processes are much more
automated in OS/390 under the theory that the system will be better utilized and
jobs run more efficiently without operator intervention.
is he given the opportunity to correct JCL errors. The processes are much more
automated in OS/390 under the theory that the system will be better utilized and
jobs run more efficiently without operator intervention.
4.2 High Level Similarities
A high level comparison of JCL in the VSE and OS/390 environments reveals
many similar functions and purposes. A comparison of the mechanics in both
environments reveals significant differences.
many similar functions and purposes. A comparison of the mechanics in both
environments reveals significant differences.
4.2.1 JCL Statement and Job Layout
VSE and MVS JCL are similar in the basic layout for the card images in that both
use 80 Column Card Images, and both use // in columns one and two. Both
operating systems also use the basic layout of a job with one or more steps per
job as described in the philosophical discussion above.
use 80 Column Card Images, and both use // in columns one and two. Both
operating systems also use the basic layout of a job with one or more steps per
job as described in the philosophical discussion above.
4.2.1.1 Continuation Cards
Both use ASM-type continuation, but the basic layout differs in that:
•
VSE JCL statements are continued by placing a non-blank character in
column 72, and JCL continuation cards must start in column 16 with blanks in
columns 1 - 15.
column 72, and JCL continuation cards must start in column 16 with blanks in
columns 1 - 15.
•
MVS JCL statements are continued by placing a trailing comma in the
parameter field, and JCL continuation cards may start in any column from 4
to 16, with
parameter field, and JCL continuation cards may start in any column from 4
to 16, with
″//″
in columns 1 and 2, and a blank in column 3.
4.2.1.2 JOB Statement Starts a Job
In OS/390 there is only one JOB statement as opposed to the VSE POWER and
VSE JOB statements. Much of the time the POWER job will equate to the MVS
job.
VSE JOB statements. Much of the time the POWER job will equate to the MVS
job.
4.2.1.3 EXEC Defines Job Step
The EXEC statement defines the job step in both VSE and MVS.
4.2.1.4 File Definitions
File definitions are required by both operating systems (TLBL, DLBL/EXTENT,
DD).
DD).
4.2.1.5 Imbedded JCL from Procedures and Libraries
Both operating systems support “canned JCL” and JCL procedures. In VSE, this
is done through procedures (using PROC=procname in the EXEC card) and with
the POWER * $$ SLI JECL statement (Source Library Inclusion). In OS/390, the
same thing can be done with the PROC or INCLUDE JCL statements,
respectively.
is done through procedures (using PROC=procname in the EXEC card) and with
the POWER * $$ SLI JECL statement (Source Library Inclusion). In OS/390, the
same thing can be done with the PROC or INCLUDE JCL statements,
respectively.
4.2.1.6 Nesting Procedures
Both operating systems allow for multiple levels of nested procedures. (MVS
allows up to 15 levels while VSE allows up to 16 levels.)
allows up to 15 levels while VSE allows up to 16 levels.)
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VSE to OS/390 Migration Workbook