cm@jet.uucp (colin manning) (05/29/91)
I have noted that when you run a DOS program under Windows that uses a graphics mode, then: 1. The program must run full screen - i.e Windows wont let it run in a window, like it will a text mode DOS prog. 2. The application runs noticeably slower than it does when not run under Windows. My questions are: 1. Is it possible to have a graphics mode DOS app run anything other than full screen ? Is there a way to configure an application (by PIF?) to get Windows to support it within a window ? 2. Performance. I guess the reason for the slowdown with a graphics intensive program is that Windows is trapping (in 386 enh mode) all the writes to the VGA registers, perhaps in addition to writes to video memory. This means that Windows can save and restore the application's idea of what state the VGA is in. Is there any way to eliminate this slowdown ? E.g if an application is prepared to shoulder the responsibility of always being able to redraw (+reinitialise) the VGA graphics screen, can you get Windows to allow it to write directly to the VGA hardware without the performance loss caused by trapping by Windows ? 3. When you run in standard mode, do the same restrictions apply ? -- - Colin Manning, cm%jet.uucp@ukc.ac.uk (world) OR cm@jet.uucp (UK only) - Disclaimer: Please note that the above is a personal view and should not be construed as an official comment from the JET project.