What is Program Properties Table in z/OS?

Question

I understood that PPT have entries for accessing protected resource by applications. What kind of entries does it maintain? Is it like, which program can access and which couldn't. Also applications needs to bypass password. What does that mean by bypassing password?

Answer 1

The PPT acronym is overloaded.

True, there is a CICS structure called PPT (Processing Program Table), but I believe that Pravin was asking about the MVS Program Properties Table. This is what the z/OS documentation has to say:

[The PPT] allows the installation to specify a list of programs that require special attributes.

Sometimes, your application programs will need to possess special properties to run as efficiently and securely as possible. For example, an application that requires access to fetch-protected system data will need a system key (0-7) instead of the usual problem program key of 8. Or, for example, an application that cannot run V=R, but must not be swapped out because of real-time considerations, will need to be identified to the system as nonswappable. Entries for these programs are created in the program properties table (PPT).

One of the PPT settings (which are specified in the SCHEDxx parmlib member) allows the specified program to bypass security protection. Meaning that a program that is flagged as NOPASS can access any dataset that it wants.

You don't want to give that authority to user programs.

Answer 2

PPT's relate to CICS applications. Until you have an appreciation as to what CICS is, any explanation of what a PPT is is not going to be of much use to you. I suggest you have a look at this IBM Redbook: CICS Transaction Server to get a general CICS overview. This document does not explain much about what a PPT is but it is valuable background.

To answer your direct question, the primary function of PPT (Program Process Table) is to register all CICS application programs and BMS mapsets. The PPT keeps track of which applications are loaded in the CICS address space. CICS uses this information to determine whether new copy of the program needs to be loaded or has already been loaded from secondary storage (e.g. disk). The PPT contains information such as the current programs location in memory, its library address on disk and language being used (e.g. COBOL).

CICS maintains many resource tables, of which the PPT is only one. Other examples of CICS resource tables include:

• Program Control Table (PCT)
• File Control Table (FCT)
• Terminal Control Table (TCT)
• DB2 Resource Control Table (RCT)
• Destination Control Table (DCT)