fg(4)fg(4)Namefg - VCB03 - Midrange VAX color video subsystem
device fg0 at ibus? flags 0x0f vector fgvint
The VCB03 is a high-performance, full-page, double-buffered video sub‐
system capable of Z-buffering. The device consists of a 2048 bits wide
x 2048 bits long x 8 or 24 plane frame buffer, a set of proprietary
video chips for bitmap modification and video output, onboard VAX CPU
and floating point accelerator, a 3D Transformation Engine, 1280 wide x
1024 long 19-inch color video monitor, keyboard, and a mouse or tablet.
The subsystem device driver supports a hybrid terminal with three minor
devices. The first device emulates a glass tty with a screen that
appears as a 80-column by 60-row page that scrolls from the bottom.
This device is capable of being configured as the system console.
The second minor device number is reserved for the pointer. This
device is a source of pointer state changes. (A state change is
defined as an X/Y axis pointer movement or button change.) When
opened, the driver couples movements of the pointer with the cursor.
Pointer position changes are filtered and translated into cursor posi‐
tion changes in an exponential manner. Rapid movements result in large
cursor position changes. All cursor positions are range checked to
ensure that the cursor remains on the display.
The third minor device is opened in the raw mode by default. Opening
the third device makes the driver function like a pseudo-tty in that
the output destined for the first minor device is channeled to the
The Hold Screen key is supported. The driver treats this key as if
CTRL/S or CTRL/Q is typed. Pressing the Hold Screen key suspends the
output if it is not already suspended. The output will be resumed by
pressing this key again (if the output was suspended).
See Alsofc(4), ttys(5), MAKEDEV(8)