CSC 453 - Operating Systems

Dr. R. M. Siegfried

Assignment #1 - p. 53-4/1.3, 1.6, 1.10

Due Friday, February 2, 2024

1.3

What is the main difficulty that a programmer must overcome in writing anr operating system for a real-time environment?

1.6

Which of the following instructions should be privileged?

1. Set value of timer.
2. Read the clock.
3. Clear memory.
4. Issue a trap instruction.
5. Turn off interrupts.
6. Modify entries in device-status table.
7. Switch from user to kernel mode.
8. Access I/O device.

1.10

Give two reasons why caches are useful. What problems do they solve? What problems do they cause? If a cache can be made as large as the device for which it is caching (for instance, a cache as large as a disk), why not make it that large and eliminate the device?

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