Many of these utilities were designed by IBM users, through the group SHARE, and then modified or extended by IBM from versions originally written by a user.
These utilities are usually invoked via Job Control Language (JCL). They tend to use common JCL DD identifiers for their data sets:
SYSIN — input file for the 'commands' for the utility. Often set to DUMMY if the default action is desired.
SYSUT1 — input file.
SYSUT2 — output file.
SYSUT3 — work (spill) file for input (SYSUT1) (often not used).
SYSUT4 — work (spill) file for output (SYSUT2) (often not used).
SYSPRINT — output file for printed output from the utility.
SYSOUT — output file for messages from the utility.
SYSUDUMP — output file for a system 'dump' if the program fails.
IDCAMS ("Access Method Services") generates and modifies VSAM and Non-VSAM datasets. The "Access Method" reference derives from the initial "VSAM replaces all other access methods" mindset of OS/VS. It probably has the most functionality of all the utility programs, performing many functions, for both VSAM and non-VSAM files. It was intended to replace most of the other dataset utility programs.Example: