Posted: September 18th, 2017

IT architecture

Please answer all questions entirely, with full explanations, follow all instructions per question

Questions

1. I/O and computer peripheral (30 points)

The average latency on a disk with 2000 sectors is about 100 msec. Seek time is 1 msec.

1. What is the rotating speed of the disk?
2. What the transfer time for one sector of data?
3. What is the total time to transfer one sector of data?

2. Input and Output (20 points)

One of the methods for communication between CPU and input/output (I/O) devices is through polling. It was said that one advantage of polling is that the CPU can determine when and how often it would like to servicean I/O device. However, this can also be achieved through the use of interrupt. Can you explain how? Give an example that shows your understanding of how this works. Be verbose.

3. Operating System (20 points)

Real time operating system is important for many applications.

1. Describe the characteristics of real time operating system. What characteristics distinguish it from normal operating systems such as windows or mac os? What makes it real time? Be verbose.
2. Research a commerical real time operating system. Write a 1-2 page essay (double space) comparing that real time operating system with a normal operating system. In order to fit within 1-2 pages, pick 3 characteristics or functionalities of the operating system to compare.

4. The internal operating system (20 points)
5. In virtual memory system, the amazing thing about a memory read or write operation is that most of the time, the memory address that CPU wants is actually already available in the physical memory (RAM). Why is that? Be verbose.
6. In virtual memory system, what would happen if a computer wants to access a memory address that is not located in the physical memory? Please be verbose.

5. Input and output (10 points)

It is possible that while the CPU is servicing an interrupt from device A (can be a DMA interrupt but it can be any kind of interrupt), device B interrupts CPU. If the CPU would like to ignore device B’s interrupt because device B is deemed to have a lower priority, how would it go about it? Be verbose.