This is a good proposition. Another attribute is underline, but that wouldn't fit in a byte, or we have to offer a bit from the colours or not flashing as this can be emulated in software if it is really needed in a program.- bit 7: 0=Text, 1=Semigraphics 6 (resolution 160x120)
- bit 6: 0=Normal, 1=Flashing
- bits 3-5: Background Colour
- bits 2-0: Foreground Colour
Scrolling takes twice as much work, but it is also possible to define two different modes in software. One monochrome mode for e.g. developing a program. In this modes there are no attributes handled by the vdu driver - or all characters have the same attribute. This gives us normal speed scrolling. In the other mode, the software updates the attributes as well, so scrolling is slower, but while in a program you can also clear the screen and start writing from the first line, so the slow scrolling isn't a problem.