After 5 days, my OS doesn't crash when I press a key
1–10 of 90 posts
Re: After 5 days, my OS doesn't crash when I press a key
#2I really like the step by step list - nothing's been removed and I can see exactly how frustrating/enlightening the process was!
Re: After 5 days, my OS doesn't crash when I press a key
#3Would echoing the chracter on screen require a seperate video driver to mark the pixels that make up the character ? Considering how hard is to make the keyboard driver, wouldn't the video driver be many folds harder?
Re: After 5 days, my OS doesn't crash when I press a key
#4Would echoing the chracter on screen require a seperate video driver to mark the pixels that make up the character ? Considering how hard is to make the keyboard driver, wouldn't the video driver be many folds harder?
Most video cards (some newer ones have stopped shipping with it) have, baked in, a text mode buffer. It's included in the Vesa Bios Extensions.
Re: After 5 days, my OS doesn't crash when I press a key
#5Would echoing the chracter on screen require a seperate video driver to mark the pixels that make up the character ? Considering how hard is to make the keyboard driver, wouldn't the video driver be many folds harder?
PC video systems support text mode, where making a character appear amounts to simply writing the correct bytes to the correct memory mapped video buffer address. Graphics mode is similar but with more bytes (say, four per pixel).
Re: After 5 days, my OS doesn't crash when I press a key
#6I really like the step by step list - nothing's been removed and I can see exactly how frustrating/enlightening the process was!
Agreed- the frustration was more than enough!
Re: After 5 days, my OS doesn't crash when I press a key
#7Would echoing the chracter on screen require a seperate video driver to mark the pixels that make up the character ? Considering how hard is to make the keyboard driver, wouldn't the video driver be many folds harder?
Text mode is super easy - you just set bytes in the correct memory location (0xb8000000 if I remember correctly).
Writing an actual graphics driver is tricky - although there are some ways to get decent frame buffer modes (like VESA Bios Extentions), to do things really well requires thousands of lines of code before you can even get a pixel on the screen, and is different for every card.
It may be a bit easier now - you could look at the kernel mode setting code in the Linux kernel that exists now for Intel, nVidia (through Norveau) and AMD cards that didn't exist a few years ago when I was dabbling around in OS dev. Still, it would be a massively difficult task. You'd probably want to use the full Mesa stack and open source drivers that use it if possible, but writing the runtime to support it would be a big task.
Re: After 5 days, my OS doesn't crash when I press a key
#8Nothing quite like trying to write a complex system from scratch to realise just how many giant shoulders you stand on every day.
Re: After 5 days, my OS doesn't crash when I press a key
#9Would echoing the chracter on screen require a seperate video driver to mark the pixels that make up the character ? Considering how hard is to make the keyboard driver, wouldn't the video driver be many folds harder?
Text mode is super easy - you just set bytes in the correct memory location (0xb8000000 if I remember correctly). Writing an actual graphics driver is tricky - although there are some ways to get decent frame buffer modes (like VESA Bios Extentions), to do things really well requires thousands of lines of code before you can even get a pixel on the screen, and is different for every card. It may be a bit easier now -…
> Writing an actual graphics driver is tricky
Does that include things that are not in text mode, if I recall the name correctly? Sometimes I just want my tiniest netbook to display the normal 80x40 resolution but it keeps putting the characters in what I think is video mode
Re: After 5 days, my OS doesn't crash when I press a key
#10Earlier quoted context omitted.
Text mode is super easy - you just set bytes in the correct memory location (0xb8000000 if I remember correctly). Writing an actual graphics driver is tricky - although there are some ways to get decent frame buffer modes (like VESA Bios Extentions), to do things really well requires thousands of lines of code before you can even get a pixel on the screen, and is different for every card. It may be a bit easier now -…
> Writing an actual graphics driver is tricky Does that include things that are not in text mode, if I recall the name correctly? Sometimes I just want my tiniest netbook to display the normal 80x40 resolution but it keeps putting the characters in what I think is video mode
I'm not sure how it is implemented at the graphics card level, but the Linux kernel virtual console can be high-resolution.
The "correct" thing to do here is set the console font to a larger one. If you are on a systemd-using distribution, see vconsole.conf(8).
Now, you could force a lower resolution, but that causes jaggy text, as pixels will be stretched unevenly by the graphics card. This can be done with KMS, or the vga= boot parameter.