How nice is graphics programming on PC video cards ! a lot of modes, no
norm but the old VGA, and only the black and white easy to use or the VESA
with its interrupts and BIOS extensions. And if we want to do protected mode
video graphics without BIOS ?
COMPUTER SCIENTISTS LET US ASK MANUFACTURERS FOR A BASIC MODERN
VIDEO MODE !!
I propose the following very simple thing :
Card manufacturers ! give us a memory mapped 1024x768 256 colours mode
with customizable base address and full data bus width addressing.
It is very simple :
We keep the DACs registers on ports h3C6, h3C7, h3C8 and h3C9 to
manipulate the palette.
And you give us a Video RAM Base Register (VRBR) accessed through a
world wide standard byte port (the VRBR Address Port, VRBR_AP) at a standard
free port address (h3CA if it is free ? ) and whose functionning is :
* after reset the VRBR is all 0 and the card is its usual reset video
mode, the VRBR_AP byte port points to the least significant byte (LSB) of
* To program the BASIC MODE, we first write each byte of the VRAM base
address to the byte port which increments toward more significant bytes (so
that if we have 64 bits addresses someday, it will just be enough to enlarge
th VRBR, if any body needs to put the video buffer out of 4 Gb ! ).
* To activate the BASIC MODE we read the VRBR_AP, which also returns
the VRBR_AP to point on the VRBR LSB.
Return to every other mode is done by classical means for those who
That will not cost a lot, it will not compete with powerful 3D hardware
modes, but it will considerably facilitate the programming of simple video
tasks. It will be a considerable plus for the manufacturers choosing such a
basic service as it allows for quick alternate system developments making
the PC platform a real de facto computer hardware standard known of
everybody. At present the lack of standard basic video makes the PC hardware
non universal and that restrains the market.
256 colours on 16 millions is enough for simple video, and each pixel
is naturally aligned.
I propose to discuss this demand, and once a good group of people
agrees on a basic video service, we contact the manufacturers, and we make a
list of responses, lack of responses etc on the network.
Every comment is welcome.