Pathway/XM System Management Manual

Configuring Clients and Requesters
Compaq NonStop™ Pathway/XM System Management Manual—426761-001
5-21
Setting the DISPLAY-PAGES Parameter for Terminal
Devices
terminal maintains to record field characteristics (for example, brightness or blinking
versus non-blinking).
The DISPLAY-PAGES parameter determines how much terminal memory is used for
the screen-image area compared to how much is used for the field-attribute entries area.
The more memory assigned to one, the less available to the other.
Figure 5-3
illustrates a terminal’s RAM organization with a DISPLAY-PAGES setting
of 3. The RAM space reserved in the screen-image area stores the image of Screen A,
Screen B, and Screen C. The remainder of the RAM is used to store the field-attribute
entries for each screen field.
Determining the DISPLAY-PAGES Value
The correct value of the DISPLAY-PAGES parameter depends on the application being
run. An inappropriate value for DISPLAY-PAGES can result in the following
consequences:
•
If the value of DISPLAY-PAGES is too large, there will not be enough room in the
terminal’s field-attribute area for all the field-attribute entries. This causes the
terminal to abort with the terminal error ALL FIELDS USED.
•
If the value of DISPLAY-PAGES is too small, the terminal’s RAM will not be used
to its full capacity. Consequently, performance is not as good as it could be because
the number of screens that could be recalled is not at its maximum.
The factors that determine the correct value for the DISPLAY-PAGES parameter are the
number of field-attribute entries per screen definition, and terminal capacity. The
Figure 5-3. RAM Organization Within a Terminal
024CDT .CDD
Screen A
Field-Attribute Entries Area: Screen A
Field-Attribute Entries Area: Screen B
Terminal Random Access Memory (RAM)
Screen-Image Area
Field-Attribute Entries Area
Screen B
Screen C
Field-Attribute Entries Area: Screen C