I won't say N book... but some of the questions have already been answered... so you should look for some info on this site...
(I'm thinkin of 7 5 and 2
I'll answer 4:
JES stands for job entry subsystem. its role is to monitor manage everything pertaining to job and spool.
the two flavors (JES2 and JES3) arose from a difference in design basically JES2 is for mono and multi image (MVS copy) sites running on one box (hardware) and JES3 is for several MVS copies running on several boxes
It's a set of standards which defines the procedence over the characters.
2) What is low-values and high-values in Figurative constants?
Low-values refers the lowest value in the collating sequence. In ASCII low-values referes B'0000000'and in EBCDIC it refers B'00000000'.
3) What is variable length and Fixed length records?
If you know the size of the table at the time of creation, it's fixed length. If you have the facility to change the size of the table depending some element, you can say it as variable length table.
4) What is JES2 & JES3?
Refer blue bird's answer
5) What is SMS?
Storage Management System
6) Why Picture clause should not specify in comp1 and comp2?
The purpose of specifying PIC clause is to specify the Data type, size & format. if you know this things already, there is no need to specify PICTURE Clause. (I beleive, I have already answered for this question)
I CAN ANSWER FEW OF THE QUESTIONS.
3. FIXED LENGTH RECORDS ARE ONE IN WHICH ALL RECORDS ARE OF SAME LENGTH. HERE, RECORDS ARE NOT CONTINUOUS IN NATURE, THAT IS EVEN IF THERE IS A SPACE IN FIRST RECORD, THE NEXT RECORD HAS TO BE INSERTED INTO THE NEXT LINE. BUT IN VARIABLE LENGTH RECORD, RECORDS ARE OF DIFFERENT SIZE AND ARE CONTINUOUSLY ARRANGED, THIS WILL REDUCE THE SPACE REQUIRED.
4. JES2 & JES3 ARE JOB PROCESSOR OF MVS.
JES2 PERFORMS SIMPLE JOB SCHEDULING FOR THE JOBS HAVING SAME JOB CLASS AND JES2 IS A DECENTRALIZED ENVIRONMENT THAT IS EACH PROCESSOR WILL TAKE UP ONE JOB. BUT JES3 PERFORMS DEADLINE SCHEDULING AND IT IS CENTRALIZED ENVIRONMENT, THAT IS THERE IS ONE GLOBAL PROCESSOR WHICH ASSIGNS JOBS TO OTHER PROCESSORS.
5. SMS IS A SUBSYSTEM OF MVS, THE MAINFRAME SYSTEMS AFTER ES9000 ARE SMS MANAGED SYSTEMS. THAT MEANS WHENEVER WE CREATE A DATASET, AUTOMATICALLY, THE DATASET WILL BE ALLOCATED TO SOME VOLUME , DCB PARAMETERS WILL BE SET AND IT WILL ALSO DECIDES WHEN THE DATASET HAS TO BE BACKED UP AND WHEH IT HAS TO BE DELETED, THAT IS IF THE DATASET IS NOT USED FROM THE LAST 6 MONTHS, THEN THAT DATASET WILL BE DELETED.THESE THREE THINGS WILL BE DONE BY STORAGE CLASS, DATA CLASS, MANAGEMENT CLASS RESPECTIVELY.
6. THERE IS A DEFAULT PICTURE CLASS DECLARATION FOR COMP-1 AND COMP-2. IT HAS BEEN DONE INTERNALLY.
7. RBA MEANS RELATIVE BYTE ADDRESS. IN CASE OF ESDS, RECORDS ARE IDENTIFIED BY RBA.