IBM System/360 20 User Manual

ment, and the last one is the EXEC state-
ment. Only LOG, NOLOG, and PAUSE state-
ments may precede a JOB statement. All
other types of job control statements must
appear between the JOB and EXEC statements
as follows:
• The CONFG statement, if required, must
precede the first TPLAB statement for a
job.
• A TPLAB control statement must directly
follow the associated VOL statement.
• If, in a set of job control statements,
a FILES statement and an ASSGN statement
~efer to the same symbolic I/O address,
the FILES statement must follow the
ASSGN statement.
• All other job control statements may
appear between the JOB and EXEC state-
ments in any order.
The JOE statement and the EXEC statement
are required in any set of job control sta-
tements. If it is intended to suspend sys-
tem operation without terminating the sys-
tem run, a PAUSE statement must be used.
When the Job Control program encounters a
PAUSE statement before it has read a JOB
statement, it causes an immediate halt. In
this case, the Job Control program expects
a set of job control statements to be read
as soon as system operation is resumed by
pressing the Start key on the CPU console.
When a PAUSE statement is encountered
between a JOB and an EXEC statement, the
Job Control program finishes reading the
set of control statements issued and causes
a system halt immediately before the load-
ing of the program is to begin. In this
case, the Basic Monitor expects to load the
program associated with the set of job con-
trol statements as soon as system operation
is resumed by pressing the Start key on the
CPU console.
At system initiation time, a DATE con-
trol statement must be submitted to the Job
Control program. If the storage capacity
of the user's Model 20 system is other than
8K and a·correct CONFG card has not been
submitted to the Load System Tape program
at the time the system tape was built, a
CONFG card is also required. The use of
any other job control statements depends on
the requirements of the first job to be
executed.
In the course of a system run, the Job
Control program is loaded and executed
whenever a program has reached the end-of-
job. It reads the next set of job control
statements from the device assigned to SYS-
RDR and sets up the system for the job to
be executed next.
I
The loading routine loads the object pro-
gram in card-image format from the device
assigned to SYSIPT and causes its immediate
I
execution. When a FETCH macro instruction
is encountered in the program, the loading
rcutine is re-entered and the next program
phase is loaded from SYSIFT. When an EOJ
macro instruction is encountered, control
is returned to the loading routine of the
Basic Monitor, which then loads the Job
Centrol program, so that the system can be
prepared for the next job.
liQ1~: The operand LOADER in an EXEC state-
ment is ignored if the preceding JOB state-
ment contained the operands
RPG,program-name.
The programmed-halt codes that may be
displayed during the execution of the Job
Control program as well as the appropriate
restart procedures are described in the
section g~Qgra~ID~d-H~l! Di§£~§_~nd
Re§tar1 PrQ£~g~~~§~
TAPE ERROR STATISTICS
Subject to the restrictions listed below,
it is possible to determine the number of
tape errors that occurred while the protlem
program was being executed.
Tape error statistics may be re~uested
during Job Control time by means of the 1/
OPTN control statement. If they are
requested, the following information is
collected for each physical unit used:
1. Successful requests - total number of
successfully completed tape cperations
reguested by the problem program.
2. Read errors - total number of read
requests not successfully completed on
the first attempt.
3. Unrecoverable read errors - total numb-
er of read requests not successfully
completed after 100 attempts.
4. Noise records - records of less than 12
bytes in length.
5. write errors - total number of write
requests not successfully completed on
the first attempt.
6. Erase gaps - repositioning and cleaning
of the tape reel by the Basic Monitor
program to correct write errors. An
erase gap is initiated and counted
every time a write error occurs.
To display tape and/or ESCA error stati-
stics, the Job Control program must be
reloaded after execution of the problem
program.
• 1he upper 280 bytes of main storage must
be free. When submitting programs for
16 System/360 Model 20 TPS Operating Procedures

IBM System/360 20 Specifications

General

Brand	IBM
Model	System/360 20
Category	Storage
Language	English