Figure 6-5. Backreferencing a Previously Identified File

For detailed information, refer to Accessing Files Pr ogrammer's Guide (32650-90017).

File Classes

The File System recognizes t wo general classes of ￿les:

User-de￿ned ￿les, whic h users de￿ne, create, and mak e available for their o wn purposes.

System-de￿ned ￿les, whic h the File System de￿nes and mak es available to all users. For example, they are used to indicate standard input/output devices.

The ￿le classes are distinguished b y the ￿le names and other descriptors (suc h as group or account name) that refer to them. Y ou can use a ￿le name and descriptors, in com bination, as either:

A formal ￿le designator in a program or ￿le equation

An actual ￿le designator that iden ti￿es the ￿le to the File System

User-defined Files

You can reference an y user-de￿ned ￿le by writing its name and descriptors in the standard ￿le reference format, as follo ws:

filename [/lockword][.groupname][.accountname]

The maximum size of a ￿le designator written in this format is 35 c haracters, including delimiters.

When you reference a ￿le that belongs to y our logon account and group, you can use the simplest form of the standard ￿le reference format; the user or system ￿le name. Specify both the actual and formal ￿le designators in the standard ￿le reference format.

The ￿le name is from 1 to 8 alphan umeric characters, beginning with a letter (unless the ￿le has a lockword, in which case you must specify the loc kword and a delimiter). In the following examples, both formal and actual ￿le designators appear in this format:

:FILE ALPHA=BETA :FILE REPORT=OUTPUT

File System 6-11