Logical names provide a way to
name objects abstractly, that is, you define a logical
synonym for some object and then use the synonym when referencing
the object. One of the benefits derived from this level
of abstraction is the idea of device independence. This
means that, for instance, you can define a logical name
for a device, such as STUDENT. Your command procedures
can reference the device as STUDENT. Should the actual
physical device have to be replaced, the only change necessary
to make your references valid is for the logical name STUDENT
to be redefined to the new device (also assuming the data
was restored to that device).
The OpenVMS operating system makes extensive use of
logical names. Some of the predefined logical names can
be useful for the general user. Users can also define
their own logical names. Logical names are stored in
tables, either the specific predefined tables or user-created
tables.
This course discusses defining and using logical names.
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