XQVSS(8)

NAME
Xqvss - X window system QVSS implementation notes

DESCRIPTION

The QVSS hardware in the DEC VS1 and VS2 is monochrome. The usable size is 864 lines by 960 pixels/line. (Future driver mods will default to 1024 pixels/line on the VR260 monitor of the VS2, in Ultrix 1.2; for VR260 monitors under 1.1, patch the kernel variable qv_def_scrn to 2.).

Probably the most irritating problem with the QVSS hardware is the cursor support, which is limited to 16x16. As only ``and'' and ``or'' operations are available in the hardware, the driver inverts the cursor depending upon the pixels below the cursor. We will eventually get fed up and implement a software cursor.

Under Ultrix-32 release 1.1 and 4.2BSD, the window system will be slightly unreliable due to a kernel problem. Fixed in Ultrix32 release 1.2. Under Ultrix-32 1.1, your best bet is to use unix domain connections (unix:0 as host spec's) for local connections.

Thanks must go to Dave Carver (and others) in the DEC Workstations group for implementing the bit-blit library. Large area bit-blit code is compiled on the fly and runs at optimal speed.

Performance is now tolerable, between 3400 and 4200 characters/second on a VS2. Performance on a VS1 is approximately 2000 characters/second. Some further improvement can be expected.

SEE ALSO
X(8c), X(1)
`Xlib - C Language X Interface'
`ddX - Device Dependent X Interface'

AUTHOR
Copyright (c) 1984, 1985, 1986 by Massachusetts Institute of Technology.
See X(1) for a complete Copyright notice.