Unformatted text preview: of the I/O. 2. (2.5 pts) Draw a Fgure to describe the layers of the I/O software and explain what each layer does. Answer: ±rom bottom to up: (a) Interrupt handler: Saves the state of the current process, processes in-terrupts generated by the devices by calling the appropriate interrupt handling procedure, and calls the scheduler. (b) Device driver: Programs the device controller by writing to its control and data registers to do I/O and to conFgure the device. (c) Device independent software: Provides protection, error reporting, bu²er-ing, etc. (d) User-level I/O software: Provides spooling, formatting, etc....
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- Spring '07
- Operating Systems, Computer program, Interrupt, Interrupt handler, Programmable Interrupt Controller, Interrupt latency, Direct memory access