## Virtual Device Driver Reference for OS/2

[prev][next][parent][TOC]

### DOS Support

The virtual timer device driver provides the following:

Virtualization of timer ports to allow reprogramming of the interrupt rate and the speaker tone frequency
Distribution of timer ticks to DOS sessions
Maintenance of the timer tick count in the BIOS data area
Serialization of Timer 0 and Timer 2 between the virtual timer device driver and the physical timer device driver