3 ms·
I think, what is often overlooked as to why the PC won the market is exactly its hi-res textmodes; 1) The BIOS was insanely slow yes. But on the other hand it
by joakleaf 5y ago
I think, what is often overlooked as to why the PC won the market is exactly its hi-res textmodes;
1) The BIOS was insanely slow yes. But on the other hand it was really fast when you wrote to the screen memory directly (address $B8000).
An entire screen in 720x400 resolution VGA, was represented by just 80x25x2=4000 bytes (2 bytes per char code + color attributes). A single plane bitmat graphics mode (just black and white) in same resolution would be 36000 bytes.
So scrolling through documents/spreadsheets was very fast compared to graphics modes, which most other platforms used. And screens used less memory.
The simple text-modes were also really easy to develop for.
2) The high-res text (720x400x16) and graphics modes (640x480x16) on VGA were non-interlaced (unlike e.g. the first Amigas), so they felt more solid and you could work with them longer before getting tired.
- rbanffy 5y agoWhile this is true - it is possible to bypass the BIOS (at the cost of "snow" on early CGA adapters), most of the competition for the IBM PC also had text modes. My Apple II+ running CP/M had a board with a 6845 CRTC, the same used in the CGA and MDA. Apple ///, //e and others had 80-column text modes pretty much built-in. While the memory layout on the Apple II was more complicated, you could call routines in ROM that were very fast. The same approach was used in later machines such as the Amiga, the Mac and the STs - using the ROM or OS routines was the standard way to do things, much like bypassing the BIOS and directly addressing the hardware was the standard way to work on the PC (remember how the "gold standard" of compatibility was being able to run Flight Simulator). With these later machines, we learned that looking to the hardware from too close was a compatibility issue.