IBM Mainframe Forum

I just want to know about IKJEFT01 utility and how it is difference from IKJEFT1A and IKJEFT1B. How these utility are related with address space .

Thanks in advance .

Regards
Gautham

In Addition to that , why we call them Terminal monitor program ?? Why we use this utility in-specific for DB2 ??Any reasons??
Please help me out .

Sorry for asking many questions .

When you interact with the mainframe via a terminal, you are generally using TSO. IKJEFT01, IKJEFT1A, IKJEFT1B are different ways to invoke TSO in batch. 1A and 1B are alternates (aliases) to 01. The basic difference is that IKJEFT01 pretty much ends with return code of 0, no matter what the commands returned. IKJEFT1A and IKJEFT1B will generally stop processing when a command gives a non-zero return code and return a non-zero return code. They are called terminal monitor programs because they are the TSO terminal interaction, moved to a batch job. You access DB2 through them because that is the way DB2 works.

Address spaces are a very different thing. An address space is created for each batch job, TSO session, or started task that is running on a z/OS system. Every program, batch or online, executes in an address space. The system keeps the separate address spaces from overlaying memory, assigns priority for processing, manages I/O, and so forth. The address space contains the application program, some operating system code, and all memory used by the program -- buffers, program memory, and so forth.

why not look at the manual Yourself
starting from here
http://publibz.boulder.ibm.com/cgi-bin/ ... s/IKJ4BK90


seaching for IKJEFT1A or IKJEFT1B ( too many hits for IKJEFT01) and landing here

http://publibz.boulder.ibm.com/cgi-bin/ ... T#FIRSTHIT

As Mr. Sample and Mr. Sorichetti very ably explained IKJEFT01 and its alternate names does essentially nothing other than establish the environment in which TSO commands and other programs run. When it is the main program for a TSO session started from a terminal it obtains commands from the terminal operator and routes output back to the terminal. When it is the main program started from batch JCL it obtains commands from the dataset specified by the SYSTSIN DD statement and writes some output to the dataset specified by the SYSTSPRT DD statement. This business of reading input and writing output is more complicated than that last two sentences imply, and this is not really an issue for this post. Much of what I know about this is more appropriately discussed in the TSO forum, not the JCL or DB2 forums.

The designers of DB2 elected to make its user interface very TSO dependent, so that even batch functions are run through IKJEFT01.