Developing a Custom Device Driver
After twiddling parallel port bits using port I/O and ppdev, the Project Trailblazer engineers decided that the potential failures due to drawbacks were unacceptable. Port I/O and ppdev approaches were error prone and risky. They needed a custom device driver for their interface circuit.
Armed with their interface circuit, port I/O, and ppdev knowledge, the Project Trailblazer engineers developed a few requirements for their first device driver:
The driver should load at startup.
When loaded, the driver should enable the latch output to drive the output modules.
The driver should shield software developers from interface logic specifics.
The driver should offer control of individual pieces of snow-making equipment ...
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