STREAM

Operation Notes

The STREAM command allows you to initiate jobs while in an interactive session by constructing your job from your terminal or by reading records from a disk or tape file. When the job is read, MPE/iX spools it onto a disk file, assigns it a job number, and processes it independently as an entity completely separate from your session. In the meantime, MPE/iX allows you to continue with your session. You can specify the queue name into which a particular job should go. The name specified overrides the queue name specified in the JOB command.

You can initiate jobs in this way only if the system operator, or a user who has been given operator capabilities, has enabled the MPE/iX STREAM facility by entering the STREAMS console command. The STREAMS console command also specifies a streaming device, which to MPE/iX appears to be the source of your job input, regardless of the device you actually use for this input. As a result, the listing device that corresponds to the streaming device (not necessarily your terminal) displays the job number assigned by MPE/iX and the listing generated by the job.

When you enter STREAM without an input file (that is, with the terminal as the default input device) during a session or a job, MPE/iX prompts you for input by displaying a greater than (>) character. When you enter STREAM for a device other than your terminal, MPE/iX does not print the prompt character.

How to Stream Jobs

Begin each job in the input file with the !JOB command and terminate it with the !EOJ command. Begin all commands with an appropriate substitute (other than colon) character, as in !JOB. When the input file is spooled to a disk, MPE/iX replaces the substitute command identifier with a colon, so that the data files are properly interpreted when executed.

After reading the !EOJ command that terminates the job, MPE/iX assigns each job a unique job number (JobID). MPE/iX also assigns each job a preset priority, unless you specify otherwise in the JOB command, and processes the job independently of the initiating job or session. Regardless of which device you use to submit the input file, all jobs in that file are treated as though they originated on the unique streaming device designated by the system operator (with the STREAMS command). The listing for each spooled job and the job number are written to the standard list device that corresponds to the streaming device. You may, however, use the OUTCLASS= parameter of the JOB command to direct the listing to another device.

How To Time Schedule Jobs

You may specify the time a job is to enter the WAIT state in absolute or relative time.

If the time specified is the same as the current time, the specified job logs on immediately. If the time specified is earlier than the current time, and DAY and DATE are not specified, a warning message is generated, and the job is scheduled for the specified time tomorrow. Otherwise, any time in the current century can be specified.

If no errors are detected, a JobID is displayed on the user's screen. If more than one job is included in the inputfile, each job is assigned a unique JobID, and all of the jobs are scheduled at the same time.

When a job is scheduled for a future time, it enters the SCHED state. When the specified time is reached, the job enters the WAIT state and is executed when system variables allow.

Terminating Streamed Jobs

To terminate interactive job input, enter a colon (:). In response, MPE XL ceases prompting for batch job input and instead prompts you for another MPE/iX command:

>:  ** Denotes end of batch job input **
 
:  ** MPE XL prompts for next command **

Pressing Break aborts the execution of this command and any job currently being entered through the command. Incompletely spooled disk space is returned to the system.

If you make an error while entering the MPE/iX JOB command, you receive an error message on your job listing device. The system operator, however, receives no indication of the job or the error.

Terminating Time Scheduled Job

Jobs that have been scheduled for STREAM execution can be terminated with the ABORTJOB command. Refer to the Introduction to MPE XL for MPE V System Administrators (30367-90003) for information on using the ABORTJOB command to terminate time-scheduled jobs.

In order to STREAM a file, you must have READ and LOCK access or EXECUTE access to that file. However, READ and LOCK access would allow general users to obtain security information within the file, such as passwords and lockwords. To allow general users to STREAM the file without giving them access to secure information, you may allow EXECUTE access only.

	NOTE: Scheduled jobs survive a START RECOVERY. Any other type of system startup causes scheduled jobs to be deleted. If a job is scheduled for introduction earlier than the system startup, the job enters the WAIT state and executes when the system parameters allow it to execute. If the system is brought down for any reason, first execute a SHOWJOB command to show the scheduled jobs. Then reschedule the jobs when the system is brought back up on anything other than a START RECOVERY. A scheduled job uses an entry in the JMAT table. Because of the limited recoverability of scheduled jobs, it is recommended that jobs be scheduled no more than a few days in advance. If a user specifies a day or date for a job, but does not specify a time, the job does not enter the WAIT state at midnight on the specified day. Instead, it uses the time that the STREAM is executed, and enters the WAIT state at that time on the specified day.

Use

This command may be issued from a session, job, program, or in BREAK. Pressing Break aborts the execution of this command and any partially streamed job.

Examples

To stream a job from a disk file, you must name the input file in the STREAM command:

 STREAM ABC

If you use a character other than an exclamation point (!) as the substitute command identifier in your job input, you must identify that character in the STREAM command. Because you enter this character as the second positional parameter in this command, you must always precede it with a delimiting comma, even when you omit the input file name (the first parameter). In the following example, an asterisk (*) is used as a substitute command identifier:

 STREAM ,*
>*JOB USER.TECHPUBS
 
>*FORTGO MYPROG
*EOJ
*#J74
*>:
 
:

If your job input file contains subsystem commands, such as commands directed to the editor, do not enter any command identifier character at the beginning of these commands. For instance, when using the editor, enter the subsystem commands as follows:

 STREAM EXAMPLE
!JOB WXYZ,WRITER.TEC 
!EDITOR   
TEXT ABC   
n
EXIT
!EOJ    
#J87    
 
:

In the preceding example, the job input file is EXAMPLE which initiates the job WXYZ. WXYZ invokes the editor subsystem where the file ABC is referenced. The EOJ command terminates the job and #J87 is the job number assigned by MPE/iX.

If you want the job listing to appear on a device other than the standard listing device associated with the streaming device, you can specify this other device in the MPE/iX JOB command. Enter:

 STREAM
>!JOB USER.TECHPUBS;OUTCLASS=12

The following section contains additional examples of using the STREAM command. For these examples, assume that the current date and time are Monday, June 8, 1987, 12:00 p.m. Also assume the job file contains a valid STREAM job.