Overview#External Security Managers (ESM) is a computing term that refers to an application outside the operating system that provides a layer of security to various system artifacts.
On z/OS there are three primary External Security Managers (ESM)
- RACF - Short for Resource Access Control Facility, is an IBM software product. It is a security system that provides access control and auditing functionality for the z/OS and z/VM operating systems. RACF was introduced in 1976
- Top Secret - Computer Associates
- ACF2 (Access Control Facility)
In 1987, acquisitions made Computer Associates the largest independent vendor of mainframe infrastructure software and dominant vendor of OS/MVS security software with CA-Top Secret (#2 market share) and CA-ACF2 (#1 market share). IBM's RACF product held the #3 market share position. I really have no idea where market share of these products are today.
More Information#There might be more information for this subject on one of the following:
[#1] - http://en.wikipedia.org/wiki/External_Security_Manager retrieved 2012-10-15