The OpenVMS User's Guide, Second Edition
A broad introductory overview of OpenVMS that focuses on command procedures, text editing and system utilities.
TABLE OF CONTENTS The OpenVMS User's Guide, Second Edition
Appendix B: File Protection
Overview
OpenVMS provides two file protection mechanisms for all system objects (files, directories, and devices): UIC (user identification code) and ACL (access control list).
B.1 UIC-Based Protection
Every OpenVMS system object has a UIC-based protection mask. You can see your own UIC by typing
$ <b class="bold">show process</b>
OpenVMS uses the UIC to identify users as well as groups of users. Table B.1 lists various forms of UICs. Every UIC has four levels of protection associated with it, as listed in Table B.2. Each protection level can be allowed or denied any of the types of access listed in Table B.3. For example, when you create a subdirectory, you can choose its protection as follows:
$ <b class="bold">create/directory/protection=(s:rwed,o:rwed,g:re,w)</b>
You can change the default UIC protection on your local system by inserting the following command line in your LOGIN.COM file:
$ <b class="bold">set protection=(s:rwed,o:rwed,g,w)/default</b>
Table B.1: Sample UICs
| UIC | Interpretation |
|---|---|
| [100,6] | Group 100, member 6 (numeric form) |
| [MUSIC, MOZART] | Group MUSIC, member MOZART (alphanumeric) |
| [MOZART] | Group MUSIC, member MOZART is understood (alphanumeric) |
| [GROUP_100, YOU] | group_100, member you (alphanumeric) |
Table B.2: UIC Levels of Protection
| Level Name | Short Form | Scope |
|---|---|---|
| System | S | All system users |
| Owner | O | User UIC |
| Group | G | All users in the same group |
| World | W | All users |
Table B.3: Types of Access for Each UIC Protection Level
| Access Name | Short Form | Scope |
|---|---|---|
| Read | R | Allocate privilege to read from a file |
| Write | W | Allocate writing privilege |
| Execute | E | Allocate privilege to execute an image |
| Delete | D | Allocate privilege... |
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