Naming Conventions for Special Symbols

When IPCS creates a symbol definition, it uses a naming convention to generate the symbol name for the control block. This naming convention calls for the concatenation of:

A prefix
One or two fixed-length numeric values

Following are three examples of symbols that IPCS considers to be special symbols.

Symbol

Associated Data and Example

ASCBnnnnn

The address space control block for address space nnnnn, STRUCTURE(ASCB). The nnnnn is decimal. (An example, ASCB1)

TCBnnnnnaaaaa

The task control block for address space nnnnn, in position aaaaa in the priority queue, STRUCTURE(TCB). The nnnnn is decimal.

The highest priority TCB in address space 1 is TCB00001AAAAA; the next TCB on the queue is TCB00001AAAAB, ....

The last two characters in this name are alphabetic and range from AAAAA through AZZZZ, BAAAA, ... BZZZZ, ....

(An example, TCB1A)

UCBddd

The unit control block for device ddd, STRUCTURE(UCB). ddd designates the device address in hexadecimal. (An example, UCB1D0)

When special symbols are entered as an argument to an IPCS subcommand, leading zero digits need not be entered. In base-26 notation, the letter “A” functions as the zero digit. IPCS recognizes the symbols without regard to whether leading zero digits are present. The symbols are converted to the standardized internal format for access to the symbol table.

Special symbols tend to be more legible to the human eye when leading zeros are removed, so IPCS strips leading zeros from the prefix prior to displaying any special symbol. When special symbols are entered containing leading “A”s, IPCS also removes them from the prefix before displaying the symbol.

Reference

See z/OS MVS IPCS Commands for a complete list of special symbols supported by IPCS.