Please tell me the difference between:
1) SYSIN AND SYSTSIN
SYSIN is a standard input DD, usually used to supply run-time parameters to the associated program.
SYSTSIN is the standard input DD (i.e. Terminal Input) for either the TSO program (IJKEFT**) or the REXX interpreter (IRXJCL).
2) SYSPRINT AND SYSTSPRT
SYSPRINT is a standard print output DD for many programs.
SYSTSPRT is the standard ouput DD (i.e. Terminal Output) for either the TSO program (IKJEFT**) or the REXX interpreter (IRXJCL).