OpenExtensions VM Support › Controlling Access to the Byte File System

Controlling Access to the Byte File System

The Byte File System (BFS) is a tree‑structured file system consisting of directories and files. It resembles the DOS file system, although the direction of the slashes is reversed from DOS.

Security for the file system directories and files is based on a UNIX model of security. Each file and directory is assigned an owning UID and an owning GID. This assignment is defined and saved in the file system, not in the external security product.

Three categories of users can access each directory and file in the BFS. They are:

• The file owner
• The group that owns the file
• All other users defined to OpenExtensions VM.

Different access levels can be set for any of these three categories. For example, permissions can be defined so that the file owner gets READ and WRITE access, a member of the file&rs.s group gets only READ access, and all other users can neither READ nor WRITE to the file.

Under CA ACF2 for VM, you must define a UID for each OpenExtensions VM user and a GID for every group used to access OpenExtensions VM. You must also assign a default group in all OpenExtensions VM user ids and give these users access to any supplemental groups needed.

For more information about the Byte File System and setting file permissions, see the IBM documents entitled OpenExtensions for VM User's Guide and VM CMS File Pool Planning, Administration, and Operation.