Programming Windows NT device drivers to operate non-interrupting embedded devices

In lightly loaded systems or in systems with constant load that is known in advance, polling may be used to save interrupt resources or to simplify testing. To enable the use of polling in other environments, we introduce two polling methods designed to work in heavily loaded systems or in systems in which the load changes dynamically. Both methods have been implemented and tested on the Windows NT platform. The first method, Adaptive-Priority Polling, is implemented as a user-level application that adjusts the priority of the polling thread according to the CPU load. The second method, Adaptive-Rate Polling, offers higher resolution at the expense of more complex implementation that requires changes in the device driver code.