Time-sharing logon (TSO/E) and started task (STC) flow

Time-sharing logons and started system tasks appear to JES as two special forms of jobs that are received from designated internal readers. In JES2, these jobs are queued in special job classes (TSU and STC) and are assigned a MSGCLASS that is set during JES2 initialization (MSGCLASS parameter on the JOBCLASS(TSU) and JOBCLASS(STC) initialization statement). In JES3, the MSGCLASS for these jobs defaults to the MSGCLASS parameter specified on the CIPARM initialization statement. The two byte of PARMID= parameter on CIPARM statement is referenced by the INTPMID= parameter on the STANDARDS initialization statement.

The time-sharing message class (MSGCLASS parameter on the JOBCLASS(TSU) or CIPARM statement) becomes the output class for all dynamically allocated SYSOUT data sets for which a class is not specified, and becomes the MSGCLASS for all submitted jobs with no MSGCLASS parameter on the JOB statement. It is, therefore, not advisable to set MSGCLASS= to a SYSOUT class that specifies OUTDISP=PURGE. See the information on output disposition for SYSOUT data sets in z/OS JES2 Initialization and Tuning Guide for further information.

Time-sharing users can dynamically allocate data sets, dynamically deallocate them (spinoff), and print them at the time-sharing terminal (OUTPUT command). JES treats a file submitted by the TSO/Extensions interactive data transmission facility as an output data set.