qv(4)qv(4)Nameqv - VCB01 (QVSS) video subsystem
Syntax
device qv0 at uba0 csr 0177200 flags 0x0f vector qvkint qvvint
Description
A VCB01 provides a half-page or full-page, user-accessible bitmap dis‐
play for graphics applications. The device consists of a 256 kbyte Q22
bus memory array, a 15-inch or 19-inch video monitor, and a VX10X-EA
mouse.
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 120-column by 80-row page that scrolls from the bottom.
This device is capable of being configured as the system console.
The second minor device is opened in the raw mode by default. Opening
the second device makes the driver function like a pseudoterminal in
that the output destined for the first minor device is channeled to the
second instead. Input and output on the first two minor device numbers
are processed by the standard line disciplines.
The third minor device number is reserved for the mouse. This device
is a source of mouse state changes. (A state change is defined as an
X/Y axis mouse movement or button change.) When opened, the driver
couples movements of the mouse with the cursor. Mouse position changes
are filtered and translated into cursor position changes in an exponen‐
tial manner. Rapid movements result in large cursor position changes.
All cursor positions are range checked to ensure that the cursor
remains on the display.
If there is a VCB01 module at the standard address, the system will use
it as the system console. All input/output destined for will use the
VCB01 instead. This is done by overwriting the device switch tables.
There is a second set of device switch entries configured for the con‐
sole that can be used as an additional terminal or printer port by mak‐
ing a special device file using major number 38 and minor number 0 and
making the appropriate entry in
Restrictions
The use of the bitmap as source or destination of I/O operations is not
supported. Minor devices 1 and 2 are read only and are the only ones
supported by the MAKEDEV script. Shared access by multiple processes
is not constrained or supported. The system only supports one VCB01.
The mouse device buffers the last 50 events (state changes). If the
console port has been enabled as an additional terminal it must be dis‐
abled before removing the VCB01 to avoid two login processes on the
same device.
FilesSee Alsotty(4), ttys(5), MAKEDEV(8)
VAX qv(4)
