windows/bios keyboard buffer question...

[Brandito]

I have a question... I started up my trusty "cmd" prompt under windows and I dumped the part of BIOS memory related to the keyboard buffer (16words). The problem is that it only contains keyboard information captured from inside the prompt. It does not capture key strokes from Internet Explorer, for example.

So my question is:
What is going on?
Does windows use different interrupts? INT9 INT16?

I guess I am lost.

Thanks,
Brandito

[penagate]

Windows doesn't use interrupts, it uses window messages. If there is a keystroke buffer it would be maintained by the keyboard driver.

[bilm_ks]

Take a look for hook functions in windows sdk also

[Javageek321]

Hiho,

sorry for bringing up this old topic but I'm somewhat confused.

"Windows doesn't use interrupts, it uses window messages. If there is a keystroke buffer it would be maintained by the keyboard driver."

I dont quite understand how this can work without an interrupt. What exactly happens when I physically press a key on my keyboard on a Windows (lets just assume WinXP although I dont know if 2k would make a difference) system and what is the difference in doing this in a Dos box ?

I hope someone can clear this up.

Greetings JG

[Al42]

The Windows kernel uses the keyboard interrupt to fill its own buffer, which is turned into Windows messages. The default low-memory keyboard buffer is program-specific - it's the buffer used by the command string interpreter, which is what's running in DOS. That buffer never gets filled when other programs are running unless they don't maintain their own buffers. (Most DOS programs used the buffer as-is, but some defined their own buffer for various reasons.)

What exactly happens when I physically press a key on my keyboard on a Windows ... system

The keyboard driver services the keyboard interrupt and loads the typed character into its (the keyboard driver's) buffer.

and what is the difference in doing this in a Dos box ?

I believe that the Windows keyboard driver still services the interrupt, but puts the character into the "DOS" keyboard buffer (sends a Windows message to the DOS box).