## MMPM/2 Device Driver Reference

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

### Caveats

The following should be considered when using the high-resolution timer:

Only the first parameter to PTMRFN is checked; no other parameters are checked.

It is possible to write to the timer count variable from another PDD and disrupt the high-resolution timer.

While TIMER0 is active (i.e., while it is taking interrupts), DOS sessions do not have access to timer 0.

Performance tools such as C Set's DDE4XTRA.SYS and Visual Age's CPPOPA3. SYS are incompatible with this driver.

Device drivers should not depend on having the first tick occur at any particular time.

If a driver registers for 1 millisecond, for example, the first tick might occur less than 1 millisecond after the registration.