Writing Device Drivers

Asynchronous Communication Drivers

Asynchronous drivers can be tested at the basic level by setting up a login line to the serial ports. A good start is if a user can log in on this line. To sufficiently test an asynchronous driver, however, all the I/O control functions must be tested, and many interrupts at high speed must occur. A test involving a loopback serial cable and high data transfer rates will help determine the reliability of the driver. Running uucp(1C) over the line also provides some exercise; however, since uucp(1C) performs its own error handling, it is important to verify that the driver is not reporting excessive numbers of errors to the uucp(1C) process.

These types of devices are usually STREAMS based.