4.3BSD-UWisc/man/cat8/Xqvss.8c

XQVSS(8)            UNIX Programmer's Manual             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 imple-
     ment 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 Works-
     tations 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 approx-
     imately 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.













Printed 1/10/87          3 January 1985                         1