High Level Assembler(HLASM) for MVS & VM & VSE


Postby dn2012 » Tue Jul 31, 2012 3:29 am


I am new to MVS Assembly.
I have been told to understand ASMA90. I need to make change on user request.
Here is our existing code:
Where should I start?

//SYSLIN   DD  UNIT=SYSDA,DISP=(,PASS),           
//             SPACE=(80,(100,100),RLSE),         
//             DCB=(BLKSIZE=80,RECFM=F,LRECL=80) 
//SYSPRINT DD  SYSOUT=&SOUT,DCB=BLKSIZE=1089,                         
//             SPACE=(121,(300,300),RLSE,,ROUND)                       
//SYSUT1   DD  UNIT=SYSDA,DISP=(,DELETE),                             
//             SPACE=(CYL,(10,5))                                     
//SYSIN    DD  DSN=&LIB(&MBR),DISP=SHR                                 
//SYSLIN   DD  DSN=*.C.SYSLIN,DISP=(OLD,DELETE)                       
//SYSPRINT DD  SYSOUT=&SOUT,DCB=BLKSIZE=1089,                         
//             SPACE=(121,(90,90),RLSE)                               
//SYSUT1   DD  UNIT=(SYSDA,SEP=(SYSLMOD,SYSLIN)),                     
//             SPACE=(1024,(100,10),RLSE),DISP=(,DELETE)               
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Re: ASMA90

Postby steve-myers » Tue Jul 31, 2012 7:20 am

The JCL you show appears to be at least part of a cataloged procedure to assemble and and link an update to something known as an IMS PCB.

The JCL EXEC and DD statements appear to be complete, though the definitions of at least 3 JCL symbolic parameters appear to be missing. As such, what we see here is a JCL question, and has nothing to do with Assembler except how to perform an Assembly and link edit.

Where should you start??

This is difficult to analyze. In your position, I would locate an existing, hopefully valid PSB definition in the library specified the the &LIB JCL symbolic parameter, arrange the JCL so the SYSLMOD DD statement in the L step does not specify IMSB.STAGE.PSBLIB since we do not want to alter a valid member in this dataset, and prepare and run a job to use this JCL. This way you can experiment without damaging anything. Once you have run this successfully you can go to your boss, show what you have accomplished, and ask, "What next, boss?"
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Re: ASMA90

Postby dick scherrer » Tue Jul 31, 2012 8:59 am


Do you have a co-worker who has successfully assembled and linked an assembler program that uses IMS? Talk with them about their process.

There should be standards that developers follow and you should follow these also.

Look for other similar modules and learn from these.

If there is an IMS dba or other support, ask them.
Hope this helps,
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