walters@osubem.UUCP (walters) (07/24/87)
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Help! Does anyone know how to change the display mode from text to
graphics and back on a 256k EGA card running **Microport UNIX SV/AT
R2.2.0**. It is easily done when in real mode running DOS through int
10h but I don't think I can use the BIOS when running SV/AT. I know all
about the EGA card and routinely program it through its registers when
running DOS. I also know all about the shared memory calls in SV/AT and
can write directly to the screen in text mode. I have tried resetting
all the EGA registers to their proper values for graphics mode 10h by
using the ioctl(fd, io_op, code) call but all I get is some sort of mode
change and a green screen. Then I try to reset it back to text mode and
still a green screen. I have to reboot to get a text screen back. I
have looked through the IBM EGA BIOS listing and when they change mode
in real mode (too many modes!) interupts are disabled and all sorts of
other wierdness. What wierdness do I need? Ideas?
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Harold G. Walters Internet: walters@ce.okstate.edu
School of Civil Engineering Uucp: {cbosgd, ihnp4, rutgers, seismo,
Oklahoma State University uiucdcs}!okstate!osubem!walters
Stillwater, OK 74078