What is the usage of LOAD command in CICS

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Hi,

What is the usage of LOAD command in CICS? in what circumstance we need to use this. Please expalin in detail.

Garry Carroll · Posted: Wed Jul 16, 2008 1:00 pm

You can use EXEC CICS LOAD to load a program or user-table module into memory, or to find the address of a module. There is an option to make the module RESIDENT which might be of use if you don't want the PPT entry to specify residence.

Regards,
Garry.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Garry,

Could you please post a piece of code which having LOAD command, and just brief the usage of this code. Because would like to know the usage while developing the CICS application program.

Garry Carroll · Posted: Wed Jul 16, 2008 1:41 pm

Hi Rai,

This code snippet demonstrates LOAD of a program which is an application table and makes it resident. The table entries are defined in DPT_TABLE_ITEM and are not updated. The table would mtypically be static as changes would require recoding of the table module.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Thanks Garry.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Garry,

I have question for you.

Suppose the table DPT_TABLE_ITEM is loaded at task no.1 and your application program gave the control back to CICS. In task no.2 once again your program received the control back, during this can i access the table using the pointer which was loaded during the task no.1?

Basically i would like to know, using LOAD command can we access the data like DFHCOMMAREA?

Garry Carroll · Posted: Wed Jul 16, 2008 3:28 pm

Rai,

The way LOAD works is that it sets the pointer to the address of the loaded program.

If the program is not already loaded, then the program is loaded and the address is set in the PPT and returned to the task. If the program is already loaded, the address in the PPT is returned to the task. In this way, any number of tasks can access the same copy of the loaded program.

It is possible to update the in-memory table but this is not recommended as the changes are not reflected back to the original load module or its source and so are lost if/when the program is re-loaded. If the program is not loaded with HOLD, re-loading can be random, being dependent on CICS memory management.

Regards,
Garry.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Garry,

To some extend i understood the concept of the LOAD. Correct in thinking that, If I load a application program using LOAD command the advantage is reduce system overhead on load and unload.

I saw a statement in our manual "To load program/table/map from the CICS DFHRPL concatenation library into the main storage"

Here DFHRPL does represents a macro to define the program in PPT?

Garry Carroll · Posted: Wed Jul 16, 2008 4:22 pm

dbzTHEdinosauer · Posted: Wed Jul 16, 2008 4:30 pm

I acept the need to 'LOAD' tables, etc.

But I don't see any advantage to loading an executable module before xctl/link. If there was, the documentation would indicate that one should.

Garry Carroll · Posted: Wed Jul 16, 2008 4:39 pm

Dick,

What I meant to convey is that CICS itself will load the module, if needed, whenever a LINK, XCTL or LOAD is performed. Certainly having to perform a LOAD before a LOAD would be amusing! Which comes first, the LOAD or the LOAD?

Garry

dbzTHEdinosauer · Posted: Wed Jul 16, 2008 4:47 pm

Garry,

I was responding to this:

Garry Carroll · Posted: Wed Jul 16, 2008 4:50 pm

Apologies, obviously replies are overlapping.....

Cheers,
Garry.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Garry,

Yes I could see the DD name DFHRPL in my CICS job which concatenated with many load libraies.

Mean while please clarify me on NEW COPY. Whenever we do NEW COPY on CICS application program, internally the new version of load module copied to load library under DD name DFHRPL?

dbzTHEdinosauer · Posted: Wed Jul 16, 2008 5:19 pm

raghav08,

my sympathy goes out to you, having to work in a one man shop, no one to ask, no one to talk to.

you keep asking very basic questions. The new copy has been covered previously.

CICS maintains its 'LOAD Library' in core (memory). A new copy simply reloads the module from the application load library (which changed when you compiled/linked your module) into CICS core.

This is a link to IBM's document server listing about every cics doc that they have: publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/FINDBOOK?filter=CICS&SUBMIT=Find

you could also visit the redbook site: www.redbooks.ibm.com/redbooks.nsf/redbooks/
to find (and then download and READ).

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

dbzTHEdinosauer,

Till now I knew that NEWCOPY will copy the new version of link edited load module of application program to CICS load libray, question i have is To which CICS load libary?

The load library under DD name DFHRPL? this what i want to confirm. My apologies, I'm not looking for what's the functionality of NEWCOPY.

Garry Carroll · Posted: Wed Jul 16, 2008 5:44 pm

Robert Sample · Posted: Wed Jul 16, 2008 5:49 pm

Garry Carroll · Posted: Wed Jul 16, 2008 5:57 pm

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Earl Haigh · Active User Joined: 25 Jul 2006 Posts: 475

raghav08

all this is pretty basic stuff. It sounds like your experience is
very limited working with mainframe environments. Someone posted earlier, you are a 1 man shop.

If thats true, then you need to ask your management to send
you to some IBM training classes.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

Earl Haigh,

Yes My mainframe experience is limited and My question could be basic, If you know the right answer please post it else stop the nuisance

Garry Carroll · Posted: Thu Jul 17, 2008 12:32 pm

dbzTHEdinosauer · Posted: Thu Jul 17, 2008 1:08 pm

Not only that, the word nuisance is not used correctly in the sentence. either 'stop causing nuisance' or 'stop being a nuisance'. You probably meant stop being a nuisance (pest).

The linkedit job has a dd statement which will tell you which of the concatenated libraries in the DFHRPL reference your job will put your executable.

Look at the JCL for your linkedit step, look at the JCL for the cics started task (both can be viewed in SDSF - or whatever spool utility you have).

If your loadlib is first in the cics concatenation, no problems. but if there are others above in the cics concatenation, you need to BROWSE those libraries to insure that a memeber of the same name as your program does not exist.

unless you have your own bootleg jcl to compile/linkedit, your systems people should have provided you with jcl that would avoid the 'same member' problem.

I went to the effort to provide the above info, because unless you are having a problem with getting your corrected module into cics, NO ONE CARES ABOUT THIS CONCATENATION, WHERE IS WHAT CRAP unless you are a systems programmer! And someone whose fundamental knowledge of MF's is barebones at best, seems to make no effort to elevate his level of knowledge on his own and expects others to take their time to do it for him, becomes a nuisance.

raghav08 · New User Joined: 03 Jun 2008 Posts: 94 Location: Bangalore

dbzTHEdinosauer,

You provided me pretty good information. I could see the the link edit load library, the same exist in the CICS jcl as well (but it's not first one).

Thanks dude.