HP b2600 Administration Guide

In overlay mode, the X server runs only in the overlay planes. Since only 3 or 4 planes are available in
the overlay planes on VRX devices, the number of colors is very limited. To operate in overlay mode,
the overlay device file should be specified as the primary screen device. For example:
/dev/ocrt # Overlay mode using 3 overlay planes
or
/dev/o4crt # Overlay mode using 4 overlay planes
In combined mode, the X server runs in both image and overlay planes. To configure the X server to
operate in combined mode, a primary and a secondary device must be specified. The
VRXSecondaryDevice is used for this purpose. For example:
/dev/ocrt /dev/crt # default visual lives in overlay planes
or
/dev/crt /dev/ocrt # default visual lives in image planes
Graphics Administration Guide for HP-UX 10.20
Page 78

HP b2600 Specifications

General

Brand	HP
Model	b2600
Category	Desktop
Language	English