DOS ain't dead

Inhibition of Cap lock key and Num lock key (Developers)

posted by bretjohn  , Rio Rancho, NM, 17.03.2013, 08:47

What <Pause> does is is issue the End-of-Interrupt for IRQ 1 (INT 9) in the hardware, which lets another keystroke be issued. But, it does not actually exit the INT 9 software interrupt handler. The computer stays "stuck" in an INT 9 software loop, but hardware interrupts are reenabled. When another keystroke is entered (any keystroke other than another <Pause>), it exits the software loop and things act normally again.

The timing issues you have with the Lock keys (Caps, Num, & Scroll) are probably just related to delays with the keyboard hardware turning the LED's on and off. The software handling part of the Lock keys just sets a flag in memory, and you wouldn't even notice it from a timing perspective.

To create a program to trap these keys so they don't do anything, or do something else, you will either need to trap INT 9 or INT 15.4F.

Complete thread:

• Inhibition of Cap lock key and Num lock key - Damien, 16.03.2013, 13:55
  • Inhibition of Cap lock key and Num lock key - bretjohn, 16.03.2013, 16:41
    • Inhibition of Cap lock key and Num lock key - Damien, 16.03.2013, 21:34
      • Inhibition of Cap lock key and Num lock key - bretjohn, 17.03.2013, 08:47
        • Inhibition of Cap lock key and Num lock key - Damien, 17.03.2013, 13:42