IFN503 Fundamentals of Computer Systems

Week 6

Q1. Write a Little Man program that accepts three values as input and produces the largest of the three as output.

You are required to use symbolic addressing as described in Lecture 4. Do not use any direct mailbox addressing.

Q2. Write a Little Man program that accepts an indefinite number of input values. The output value will be the largest of the input values. You should use the value 0 as a flag to indicate the end of the input.

Q3. Write a Little Man program that outputs the sum of n number of input values.

Q4. For your LMC assembly language source codes written for Q1, Q2 and Q3, write the final machine code for each of these source codes using the following steps of the LMC two pass assembler:

1. Draw the Symbol Table.
2. Write the partial LMC machine code after the first pass.
3. Write the final LMC machine code after the second pass.

Week 7

1. Suppose that the following instructions are found at the given locations in memory:

20 LDA  50

21 ADD  51.

50 DAT  724

51 DAT  006

(a) Show the contents of the IR, the PC, the MAR, the MDR and A at the conclusion of instruction at address 20.

(b) Show the contents of each register as each step of the fetch-execute cycle is performed for instruction at address 21.

Why are there two different registers (MAR and MDR) associated with memory?

Describe briefly how these two registers operate and how one is related to the other.

What are the equivalents in the Little Man Computer?

Suppose that the instruction format for a modified Little Man Computer requires two consecutive locations for each instruction. The high-order digits of the instruction are located in the first mail slot, followed by the low-order digits. The IR is large enough to hold the entire instruction and can be addressed as IR [high] and IR [low] to load it. You may assume that the op code part of the instruction uses IR [high] and that the address is found in IR [low].

Write the fetch-execute cycle for an ADD instruction on this machine.

File management

What is the difference between logical and physical view of files?

1) What are sequential files?

2) What are random access files?

3) What two powerful advantages are achieved in separating the file system functions and I/O functions into different tasks?

4) What is the disadvantage of the File Allocation Table, or FAT, disk organization?

4) Describe the Bitmap method for maintaining free space on a disk.

5) What is an acyclic-graph directory?

6) Which Internet protocol is commonly used to transfer files from one system to another?

7)Traditional network file access uses a client-server approach. What are the drawbacks to this approach in large enterprise systems?

Operating Systems

1) What is a common example of a “user” that is not a human?

2) Why is there a need to have resident and nonresident components? 

3) The file management system provides access to information about each file in the system and tools to access that information. What information about each file might this include?

4) There are two levels of scheduling. One level of scheduling determines which jobs will be admitted to the system and in what order. What does the other level of scheduling do?

39) What is the difference between preemptive and non-preemptive switching?

40) What is an embedded system?