IT Governance, Risk, and Compliance

Oct 25 2012   3:31AM GMT

Essential Operating System Protection Mechanisms – Part V

Robert Davis Robert Davis Profile: Robert Davis

Technically, the user program subroutine integration process is known as linkage editing. Linkage editing poses two risks: the unauthorized use of subroutines and the unauthorized suppression of subroutines that should accept utilization. In the first case, an application program might utilize a job control (script) statement requesting the services of an unauthorized subroutine that performs an illegal task. In the second case, the program might use a script statement that suppresses the services of a required subroutine. Consequently, policies and procedures should be implemented to ensure:

  • error messages are displayed or other action taken when reference is made to unauthorized subroutines, or when external references are unsolved
  • the operating system maintains a log of program usage
  • the linkage editor of the operating system maintains a processing history of each program, including control statements utilized


Davis, Robert E. IT Auditing: Assuring Information Assets Protection. Mission Viejo, CA: Pleier Corporation, 2008. CD-ROM. Unabridged (v 1.1). rev. ed. New York, NY: Random House. editor (accessed: August 30, 2008).

Lyon, Lockwood and Kenniston W. Lord. CDP Review Manual: Covering the ICCP, CDP, CSP, and CCP Examinations, 5th ed. New York, NY: Van Nostrand Reinhold, 1991. 130-2

Minasi, Mark. Complete PC Upgrade and Maintenance Guide, 8th ed. San Francisco, CA: SYBEX, 1997. 263-4

Watne, Donald A. and Peter B. B. Turney. Auditing EDP Systems. Englewood Cliffs, NJ: Prentice-Hall, 1984. 239

Silbershatz, Abraham and Peter B. Galvin. Operating System Concepts, 4th ed. Gainesville, FL: Addison-Wesley, 1995. 49-50

View Part I of the Essential Operating System Protection Mechanisms series here


Post Note: “Essential Operating System Protection Mechanisms – Part V” was originally published through under the title “Essential Operating System Protection Mechanisms”

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