Lockwords

Lockwords are ￿le \passw ords" which provide a primary lev el of ￿le securit y by restricting access to a ￿le to users not kno wing the ￿le's loc kword. These loc kwords may be assigned to a ￿le when the ￿le is created with the BUILD command or when the ￿le is renamed. T o delimit the lockword, enter a forward slash (/) follo wing the ￿le name:

BUILD MYFILE/KEY

RENAME MYFILE/LOCK

For additional information, refer to the MPE/iX Commands Reference Manual Volumes 1 and 2 (32650-90003 and 32650-90364).

MPE/iX File Access System

The HP 3000 system includes a set of securit y provisions with eac h account, group, and individual ￿le. This set speci￿es restrictions on access to a single disc ￿le or to all disc ￿les in a particular accoun t or group.

The restrictions are based on three factors:

Modes of access (for example, reading, writing, or sa ving).

Types of user (for example, a user with Accoun t Librarian capability , Group Librarian capability, or a user to whom the access modes speci￿ed are permitted.)

The security provisions for an y ￿le describe the permitted access modes for v arious users of the ￿le.

Specifying and Restricting File Access by Access Mode

When a program opens or creates a ￿le, it can de￿ne the w ay the ￿le can be accessed b y specifying a particular access mode for the ￿le (for example, read-only , write-only, update, and so on). These speci￿cations apply to ￿les on an y device, and only the creator of ￿le can change or override them.

When specifying the access mode for a ￿le, it is important to kno w the location of the curren t end-of-￿le before and after the ￿le is opened and the location of the logical record poin ter that indicates where the next operation will begin. F or example, the choice of the correct access mode can write a record to a ￿le and:

Append it following the last record or o verwrite an existing record.

Correct information in a ￿le rather than delete it.

Redirect output from one device to another.

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

Table 6-8 describes the ￿le access mode t ypes.

6-38 File System