1) At whast stage DB2 must be up? - Stage of what? if you are talking about the program compilation bind and all of that then DB2 should be up at the time of binding. Compiler doesn't need DB2 to be up. If you are talking about execution of a DB2 program or executing IO on DB2 tables then DB2 should be UP.
2) can you see s9(4) comp3 data?. - It is not a 'display' data type so NO. However, one can see the content by doing "Hex On".
3) what is low values and high values? - Low values is equivalent to null. I.e. hexadecimal zeroes X'0000'. High Values is hexadecimal highest i.e. X'FFFFFF'
4) In my JCL, the 1st step is Delete step. if the dataset is existing, i want to delete that one. If dataset is not existing, i don't want to abend the job. How can we code DISP? YOu can use IEFBR14 utility with DISP = (MOD,DELETE,DELETE)
5) How to see the status of the table?. -display database(DB2)
6) I have update row in table using Spufi. How to revert the update row?. That means original position? Using spufi means the change has been comitted already so rollback won't work. You can't.
7) By opening an empty VSAM file in i/p or i-o mode, you will get file status of 35. How can we overcome this?. You CAN open the empty vsam file in I-O mode if you have coded the file for random or dynamic access and the file is optional.
Optional files are files that are not necessarily present each time the program is run. You can define files opened in INPUT, I-O, or OUTPUT mode as optional by defining them with the SELECT OPTIONAL phrase in the FILE-CONTROL section of your program.
Also Sort products are capable of handling an empty VSAM file by coding the parms VSAMEMT=YES.
8) How to Input data in COBOL from JCL? - using ACCEPT and provide data in SYSIN.
9) How to copy a program in CICS? If you are talking about introducing a new CICS program you will need to define a new transaction or associate it with existing tran by updating your PPT. make an entry in PCT and TCT as required. Also if program is accessing DB2 you will need to make any entry in RCT resource Control table. If an existing program in modified and needs to reflect that change, then in CICS you can do it with CEMT S PROG(prog_name) NEWC.