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Monochrome graphic cards
Posted: Fri Nov 12, 2004 4:30 am
by ManOfSteel
Hello,
I would like to know how much monochrome graphic cards are still used.
Also, do they work in the same way that color graphic cards? Will I only have to change '0xB8000' to '0xB0000' and still write the character and the attribute? What will happen if I write in the attribute byte the code for a color, will the character be printed in white or grey or it will not be printed at all?
Thank you for your help.
Re:Monochrome graphic cards
Posted: Fri Nov 12, 2004 5:21 am
by Solar
The attribute byte is interpreted differently for monochrome displays (blinking, underline, halfshade etc., don't remember the details anymore but I got it somewhere from the FAQ).
As for usage... I'd daresay none in the desktop arena, but I know several monochromes are in use in the admin arena, where minimal systems are used to hook up to and control big-iron servers.
Re:Monochrome graphic cards
Posted: Sat Nov 13, 2004 6:14 am
by Xardfir
Yes! Yes!
I have an original Hercules video card (MDA+ graphics). It is currently in my 486SX 25.
Why these cards are just sooo good, is that under Turbo Pascal, I can see the program running on my VGA and the code as it runs on the monochrome card. Pure programming heaven!
Today I am stuck on a single monitor, though a pentium II I own has two video cards (PCI and AGP).
As for programming MDA - it follows the same as CGA (attribute, text), but the attribute is setup as follows -
7 6 5 4 3 2 1 0
| | | | | | | |
| | | | | | - - - - - Character colour
| | | | | - - - - - - - Colour intensity (0 normal / 1 high)
| | |
| - - - - - - - - - - - - Background colour
- - - - - - - - - - - - - Blinking (0 off / 1 on)
So for a black on black everything is 00000000.
For white on black 00000111.
For black on white 01110000.
For white on white 01110111.
Of course, the intensity bit can be switched on for "brighter brights and whiter whites" (OMO computer corp). ;D
MDA cards are frequently looked down upon being monochrome and everything. However, they had a much higher text resolution than CGA and EGA (720x350 compared to 640x200 and 640x350). For a lot of text work (ie spending all night in front of a computer typing) MDA was very easy on the eyes. Up until recently places like hospitals kept the old 'amber' (orange and black) screens going for this reason (OS deving for Nurses?)
The Hercules card I have can also do graphics (720x348) which was a lot better than the CGA and of higher resolution than the EGA.
Keep safe.
P.S. For anyone confused - OMO is a brand of clothes washing powder.