.\" SCCSID: @(#)qd.4	8.1	9/11/90.TH qd 4 VAX.SH Nameqd \- VCB02 (QDSS) video subsystem.SH Syntax.B "device qd0 at uba0 csr 0177400 flags 0x0f  vector qddint qdaint qdiint".SH Description.NXS "qd interface" "VCB03 video subsystem".NXR "VCB03 video subsystem".NXS "QDSS" "VCB02 video subsystem"A VCB02 provides a half-page or full-page user-accessible bit map display forgraphics applications.The device consists of a 256kb Q22 bus memory array,a 15-inch or 19-inch video monitor, and a VX10X-EA mouse..PPThe subsystem device driver supportsa hybrid terminal with three minor devices.The first device emulates a glass tty with ascreen that appears as a 120-columnby 80-row page that scrolls from the bottom.This device is capable of being configured as the system console..PPThe second minor device is opened in the raw mode by default.Opening the second device makes the driver function like a pseudoterminalin that the output destined for the first minor device is channeled tothe second instead.Input and output on the first two minor device numbers are processed bythe standard line disciplines..PPThe 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 axismouse 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 positionchanges 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..PPIf there is a VCB02module at the standard address, the system will use it asthe system console.All input/output destined for .PN /dev/consolewill use the VCB02 instead.  (This is done by overwriting the device switch tables.)There is a second set of device switch entriesconfigured for the consolethat can be used as an additional terminal or printer portby making a special device file using major number 38 and minor number 0and making the appropriate entry in .PN /etc/ttys ..SH Files.PN /dev/qd?.br.PN /dev/qconsole.SH See Alsotty(4), ttys(5), MAKEDEV(8)