What is the use of SYSPRINT, SYSIN, DUMMY in JCL ? 

TYPERUN=SCAN on the JOB card or use JSCAN.

TYPERUN=HOLD on the job card.

it is used for syntatical checks and direct job to spool and hold it.

An in-stream PROC is defined right in the jcl stream and doesn't reside in the proclib. This is an older technique associated with punched cards but it is still in use with setup and installation programs from vendors.

for the in-line perform instead of:

perform add-paragraph until switch = 'y'

you can code

perform until switch = 'y'

body of code

end-perform

body of code is the code from add-paragraph appearing in-line (ie right in the perform) instead of in a separate paragraph (out of line code)

Return Code in JCL can b obtained by the use of COND paramater...it is used to know the return codes of previous steps.

All indicate dataset out of space. SD37 - no secondary allocation was specified. SB37 - end of vol. and no further volumes specified. SE37 - Max. of 16 extents already allocated.

Batch DL/I

MPP Mode - (Message Processing Program)

BMP Mode - (Batch Message Processing)

Key Fields - (PROCOPT=K)

- Used to sequence the database and can't be changed

- It is the field within a segment, used to identify the occurrence of the segment

- Used to maintain the IMS segments in ascending sequence.

Search Fields - (PROCOPT=G)

- Used to search for a segment, without the segment being sequenced on that field

- A segment need not have a key or search field.

Both types of fields can be used to search the database.

A Field that DL/I uses to maintain the segments in the ascending order is called the key field

IMS (Information Management System) is IBMs hierarchical database management system. It has mainly two components: IMS DB and IMS DC (Also know as IMS TM)

IMS DB - IMS/Database Manager as the name implies manages the IMS databases. It is used for physical storage creation and management and data retrieval.

IMS DC / IMS TM - IMS/Data Communications or IMS/Transaction Manager handles online transaction processing system.