gtpp2m0jProgramming Standards

Generally Reserved Names for the TPF System

The letters I, i, TPF, TPF_, tpf, and tpf_ are reserved for future use by IBM. This standard applies to the following names.

TPF File System File Names

The TPF file system file names reference links to file system objects. These objects include:

You can access any file system object other than tmpfiles by name. The file system file names have as many as 256 characters and contain a hierarchical directory structure that is largely compatible with the Portable Operating System Interface for Computer Environments (POSIX) standards, although this directory structure does not contain executable files.

Note:
The TPF system does not implement the POSIX standards, and the TPF file system application programming interface (API) functions are not POSIX compliant, although they are modeled after the POSIX standards and, for the most part, are POSIX compatible.

TPF Collection Support Data Store Names

A TPF collection support data store (DS) is a named set of collections residing in a TPF subsystem. DS names are limited to 8 characters.

Symbolic Register Names

Register naming conventions for TPF system programs now require the use of the equated values R0-R15. See the following table.

New Register Names
Old Register Names

 R0 
RAC, RG0, R00

 R1 
RG1, R01

 R2 
RGA, RG2, R02

 R3 
RGB, RG3, R03

 R4 
RGC, RG4, R04

 R5 
RGD, RG5, R05

 R6 
RGE, RG6, R06

 R7 
RGF, RG7, R07

 R8 
RAP, RG8, R08

 R9 
REB, RG9, R09

 R10 
RLA

 R11 
RLB

 R12 
RLC

 R13 
RLD

 R14 
RDA

 R15 
RDB

Coupling Facility Structure Names

There are two types of coupling facility (CF) structures:

Logical Record Cache Names

A logical record cache provides high-speed access to data, which enables you to develop data sharing programs with improved performance. You can use a logical record cache for data consistency, which ensures the validity of the data that is shared and keeps track of data that resides in permanent storage and the local cache.

Tape Names

IBM reserves all tape names that have a numeric value (0 - 9) as the second character; for example, A4X or B2B.

Recoup Descriptors

The following recoup descriptors are reserved for customer use: