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 |
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