Open System Services Programmer's Guide

Figure 5 Guardian Files in the OSS File System
File Types
Using OSS functions, you can read and write only odd-unstructured Guardian files. EDIT files are
unstructured files, and you can access them only for reading. OSS functions cannot access structured
Guardian files (SQL, entry-sequenced, key-sequenced, and relative). You can access structured
Guardian files using Guardian procedure calls in an OSS program.
File Access
Guardian file access is determined by the RWEP character string. This is a four-character string;
the positions determine who can Read, Write, Execute, or Purge a file (hence RWEP). For further
information about Guardian file security, refer to the Guardian User’s Guide.
Two Process Types
You can create and manage both OSS and Guardian processes in the OSS environment. OSS
and Guardian processes share some process identifiers and attributes. OSS processes can belong
to process groups, while Guardian processes cannot. Guardian processes can belong to process
pairs, but OSS process pairs are supported only on J06.14 and later J-series RVUs and H06.25
and later H-series RVUs. (For details of OSS process pairs, see “OSS Process Pairs” (page 158).)
32 Overview of the OSS Programming Environment