File Pools, Directories, and Files

File pools are sets of VSAM files. The first VSAM file in the pool contains information about the pool and must be formatted before data can be written to the pool. All other VSAM files in the pool are extensions of the first file and only need to be defined in the pool's list of VSAM files after they have been allocated and defined to Access Method Services and CICS®. VSAM files can be added to a file pool, at will, to provide additional storage space in that pool. However, defining and adding space to file pools is a task for REXX/CICS administrators or CICS Systems Programmers. File pools are given a unique one to seven character name.

In each file pool, there is a root directory. The root directory for a file pool is named file_pool_name:\. This directory can contain files as well as subdirectories. A subdirectory is a directory within another directory. Subdirectories can be created within any other directory. A new directory can be created with the RFS MKDIR command. All directories, except the root, are distinguished by a one to eight character directory file name joined, by a period, with an optional one to eight character directory file type. This is called the directory ID.

A file pool may be defined to be a user or non-user file pool. One directory that should exist in all user file pools is the USERS directory. This directory contains several subdirectories that correspond to the users on the system. When you save a file into the RFS for the first time, a new subdirectory is created in the USERS directory. This new directory is named with your user ID if you are signed onto CICS. Otherwise, the directory name will default to the CICS DFLTUSER value. After this directory is created, you can create any number of subdirectories within that personal directory. You can place files in any of the directories that you create.

Files are either data files or REXX execs. They use the same naming conventions as directories (a file name and an optional file type joined with a period). The default file type for REXX execs is EXEC. Files are created with the REXX/CICS editor or with the RFS DISKW command.

A fully qualified file ID consists of a file pool name followed by a :\, each directory's ID in the path followed by a \, and the file ID, that is comprised of a file name and an optional file type.

The following example shows a fully qualified file ID. POOL1 is the file pool name, USERS and USER1 are directory ID's, and TEST.EXEC is the file ID.

Example:

POOL1:\USERS\USER1\TEST.EXEC

The following example shows file pools, directories, and files.

Example:

POOL1:                                   File Pool
       \                                 Root Directory
        TEST1.EXEC                       File
        USERS\                           Subdirectory
              USER1\                     Subdirectory
                    TEST2.EXEC           File
                    DOCS\                Subdirectory
                         TEST3.DOCUMENT  File
              USER2\                     Subdirectory
                    LETTER.DOCUMENT      File
        PROJECT1\                        Subdirectory
                 PROD1.EXEC              File
                 DATA\                   Subdirectory
                      PROD1.DATA         File

WORK:\                                   File Pool and Root Directory
      TEST1.DATA                         File
      CHARTS\                            Subdirectory
             CHART1.DATA                 File
             CHART2.DATA                 File

This example shows two file pools (POOL1 and WORK). File pool POOL1 contains a file (TEST1.EXEC) and two subdirectories (USERS and PROJECT1). Inside the USERS subdirectory are two subdirectories (USER1 and USER2) that correspond to user IDs (USER1 and USER2). User USER1 has a file (TEST2.EXEC) and a subdirectory (DOCS) inside its directory. Inside the DOCS subdirectory there is another file (TEST3.DOCUMENT). User USER2 has a file (LETTER.DOCUMENT) inside its directory. File pool WORK contains a file (TEST1.DATA) and a subdirectory (CHARTS). Inside subdirectory CHARTS are two files (CHART1.DATA and CHART2.DATA).