Utilities Top Ten

Utilities Top Ten

There's no specific definition of what constitutes a z/OS utility program. The UNIX community considers many standard commands (including compilers, backup programs, filters, and many others) as utilities. To the z/OS community, these are simply applications or programs. Generally speaking, z/OS utilities are batch programs, and tend to have similar requirements in JCL.

What's JCL?

Job Control Language (JCL) is used to tell the system what program to execute, followed by a description of the program's inputs and outputs. It's possible to submit JCL for batch processing or start a JCL procedure (PROC), which is considered a starter task.

Back to the Utilities...

For z/OS, there's only a small number of system-provided utilities. This has led to a proliferation of customer-written utility programs, widely shared by the user community. Third-party software vendors provide similar products, many of which have functions not included with the IBM-provided utilities.

This alphabetical listing offers a range of them, covering several operational aspects of the mainframe environment.

1. ACF/2

ACF/2 (a.k.a. CA-ACF2) is the Access Control Facility, a set of programs from Computer Associates which enable security on mainframes.

ACF/2 prevents accidental or deliberate modification, corruption, mutilation, deletion, or viral infection of files. Any authorized or unauthorized attempt to gain access to a system is logged, and system status can be monitored on a continuous basis.

A permanent usage log can be created to help identify potential intruders, and to establish and analyze changes and trends in the use of a system.


This is the primary disk dump and disk restore program provided with z/OS. It's capable of filtering and selecting which data sets to dump or restore, to provide a backup of the disk contents. A backup is usually written to tape, but can be written to a disk data set. 


The CASPLIT utility from CA Technologies reduces the time taken to FTP very large files directly from mainframe z/OS systems. Instead of sending one large file, CASPLIT first compresses the data then splits it into smaller segments and FTP multiple segments concurrently. The program's panel generates the JCL required to do the compression, splitting of the file, and FTP of the segments.

4. Data set utilities

The term ‘data set’ refers to a file containing one or more records (e.g. medical or insurance records) that are used by a program running on the system.

Data set utilities reorganize, change, or compare data at the data set or record level. The programs are widely used in batch jobs.

These utilities let you manipulate partitioned, sequential or indexed sequential data sets, or partitioned data sets extended (PDSEs), which are provided as input to the programs. Data ranging from fields within a logical record to entire data sets can be manipulated.

5. DB2 core utilities

Most of the basic utilities offered by IBM, such as LOAD and COPY, are online utilities, which require DB2 to be up and running. DB2 online utilities run as standard batch jobs or stored procedures. They don't run under control of the terminal monitor program (TMP), and have their own attachment mechanism. They invoke DB2 control facility services directly.

Core utilities are included (at no extra charge) with the current version of DB2 for z/OS:

6. DB2 Utilities Suite

All other utilities are available as a separate product called the DB2 Utilities Suite for z/OS. The suite has several components, including BACKUP SYSTEM, CHECK DATA, MODIFY RECOVERY, and RESTORE SYSTEM.

7. Endevor

CA Endevor Software Change Manager (CA Endevor SCM) can automate the software development process, and shorten the learning curve for application developers. It integrates with IBM Rational Developer for System z to accelerate time-to-delivery, and improves the auditing of programmer activities. 


The data set utilities described above can't be used with VSAM data sets.

In a Virtual Storage Access Method (VSAM) key sequenced data set (KSDS), records are data items stored with control information (keys) so the system can retrieve an item without searching all preceding items in a data set.

IDCAMS is the program name for access method services, which is used primarily to define and manage VSAM data sets and integrated catalog facility catalogs.

9. RMF

Resource Measurement Facility (RMF) is an optional IBM licensed program used to measure various aspects of system performance. Different RMF modules provide long-term statistical gathering, instantaneous data, long-term reporting, batch-type reports, TSO-oriented reports, etc.

10. Top Secret

While many organizations focus on firewalls, intrusion detection systems, virus prevention, and VPNs, they don't spend enough time and resources on the bigger risk posed by lax internal security.

Computer Associates’ Top Secret provides many functions including system entry validation, individual accountability, auditing, resource access control, and security administrator control, to protect the integrity of the mainframe as a file, web and application server.

Each Top Secret user has a unique ID called an ACID (Accessor ID). User access can be restricted to permit access only to certain facilities or resources. Each ACID is assigned access privileges, which are maintained in the user’s Security Record. In turn, all the Security Records are held in the overall Top Secret Security File. And the Security File is an encrypted database containing all user access permissions.