First post, by clb
I have been wondering why CGA standard had support for two 320x200 4-color video modes, mode 04h and mode 05h, which seem to behave the same on my VGA cards.
On the Wikipedia page about CGA Adapter: https://en.wikipedia.org/wiki/Color_Graphics_ … _graphics_modes it says that Mode 05h was basically Mode 04h, but with a different color palette compared to the two color palettes available in Mode 04h.
I have a few different VGA ISA and PCI color adapters, and all of those that I tested, Mode 05h behaves identical to Mode 04h. That is, there is no LIGHT RED color displayed, but instead the third color shows as MAGENTA instead, just like in Mode 04h.
I wonder if the light red color was more like a bug/unintended artifact, that was a side result of disabling color bursting, rather than an intended effect? And that is why the newer standards did nor perpetuate that color change? Or do you think the newer VGA color adapters were just a bit sloppy in implementing support for the CGA color modes?