Utilities to show keyboard blocking?

Question

Quoting from the Wikipedia article, Rollover (key):

Modern keyboards detect ghosting and instead of registering a fourth key will ignore the third key, which is known as blocking.

Are there utilities that run on a PC and that allow me to check if the keyboard is using blocking to prevent ghosting? (I am using a ThinkPad keyboard.)

Answer 1

Key blocking can be seen quite easily in Windows XP, and possibly even without OS. Example, using the German keyboard on a Thinkpad T41:

1. Hold E

2. Hold R

   Result: r is repeatedly printed on screen.

3. Hold T

   Result: Windows will stop repeating r; instead, it will beep. Likely explanation: Otherwise the keyboard controller can not distinguish between E and R (ghosting).

4. Release T

5. Hold W

   Result: This time, the character is displayed without problem, showing a w repeating on screen.