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Chapter 4
Software Reference
© National Instruments Corp.
4-27
GPIB-410 User Manual
Selecting one of the
ROM
BIOS
options causes all screen output to be
directed through the built-in video services of the host PC. Using ROM
BIOS calls is the most "well-behaved" manner of writing information to
the computer screen, but it is also the slowest. You should select one of
these options only if you intend to run the GPIB-410 software under one
of the windowing software packages available commercially for DOS
applications.
Note:
The GPIB-410 software has not been tested nor determined to
be fully functional under any particular windowing environment.
Selecting one of the
Direct
output options causes most screen output
to be written directly to the display memory of the host PC. Using one
of these techniques results in much faster screen updates and can also
improve overall program performance. For most display hardware in use
today, the
High-Speed
Direct
options work satisfactorily.
Some older video adapters, such as the IBM Color Graphics Adapter
(CGA) and its compatibles, produce an annoying snow-like effect on the
screen when display memory is written to directly. This problem can be
reduced or eliminated by synchronizing all screen output with the
horizontal and vertical retrace cycles of the CRT Controller hardware.
If you observe this problem when using one of the
High-Speed
Direct
options, you should select the corresponding
Synchronized
Direct
option instead. Although output using this technique is slightly
slower than that of the high-speed option, it is typically only noticeable
on slower machines.
Computer Keyboard Mode
Use this field to specify the keyboard layout of the host PC. There are
six options.
•
U.S. English
•
German
•
U.K. English
•
Italian
•
French
•
Spanish
The information in this field determines which set of keys the software
uses for all GPIB key select fields (for example, the Monitor window
toggle switches).