comp229-exercises-solution-8 - System software Review...

System software Lesson 8 – Device management comp229
Department of computer science Page 1 of 4 Fall 2003
Review exercises
8.1 Define the terms (i) device (or I/O) manager, (ii) device driver, (iii) device handler,
and (iv) device controller.
(i) A device manager is the kernel component that implements the data structures and the
system calls that are required to perform I/O operations.
(ii) A device driver is a software that is used by the device manager to perform I/O
operations for the processes.
(iii) A device handler is a module of a device driver that is called by the kernel to service
an interrupt request for a specific device.
(iv) A device controller is a hardware component that is part of a device and that
connects the device to the computer through the bus. The device driver uses the device
controller to operate a specific device.
8.2 Explain how the file manager interacts with the device manager when I/O operations
are performed.
• The file manager provides the first level of abstraction to a device and exports an
interface to processes to request I/O operations. The device manager then routes the
high-level I/O requests from the processes to the appropriate devices.
8.3 Explain a situation where the process manager interacts with the device manager to
handle an I/O operation for a process.
• When a process performs a blocking I/O operation, the I/O manager calls the process
manager to schedule another process while the I/O operation is in progress.
• Once the I/O operation is completed, the I/O manager calls again the process
manager to reschedule the process that was blocked on the I/O operation.