Exercise 6.9 Communicating with I/O devices is achieved using combinations of polling, interrupt handling, memory mapping, and special I/O commands. Answer the questions about communicating with I/O subsystems for the following applications using combinations of these techniques.

a. Video Game Controller

b. Computer Monitor 6.9.1 [5] <6.6> Describe device polling. Would each application in the table be appropriate for communication using polling techniques? Explain.

6.9.2 [5] <6.6> Describe interrupt-driven communication. For each application in the table, if polling is inappropriate, explain interrupt-driven techniques that could be used.

6.9.3 [10] <6.6> For the applications listed in the table, outline a design for memory-mapped communication. Identify reserved memory locations and outline their contents.

6.9.4 [10] <6.6> For the applications listed in the table, outline a design for commands implementing command-driven communication. Identify commands and their interaction with the device.

6.9.5 [5] <6.6> Does it make sense to defi ne I/O subsystems that use a combination of memory mapping and command-driven communication? Explain your answer.