Introduction to Computing - Unit 0 - Review Questions & Answers from 8051 Microcontrollers & Embedded Systems by Mazidi

Unit - 0:  Introduction to Computing

Section 0.1 -  NUMBERING AND CODING SYSTEMS

1. Why do computers use the binary number system instead of the decimal system? 

2. Convert 34 decimal  to binary and Hex 

3. Convert 110101 binary to Hex and decimal 

4. Perform binary addition: 101100 + 101 

5. Convert 101100 binary to its 2's complement representation 

6. Add Hexa decimal numbers:  36B and F6 

7. Subtract in Hexa decimal: 36B - F6 

8. Write "80x86 CPUs" in its ASCII code (in Hex form) 

Answers: 

1. because each bit can have one of two voltage levels: ON and OFF 

2. 34 decimal = 100010 binary = 22 Hexadecimal

3. 110101 binary = 35 hexadecimal  = 53 decimal

4. 1110001 

5. 010100 

6. 461 

7. 275 

8. 38 30 78 38 36 20 43 50 55 73 

Section 0.2 - DIGITAL PRIMER

1. The logical operation ___________ gives a 1 output when all inputs are 1. 

2. the logical operation ___________ gives a 1 output when 1 or more of its inputs is 1. 

3. the lgoical operation ___________ is oftern used to compare if the two inputs have the same value. 

4. A __________ gate does not change the logic level of the input. 

5. Name a common use for flip-flops 

6. An address ________ is used to identify a predetermined binary address. 

Answers: 

1. AND 

2. OR 

3. XOR 

4. Buffer 

5. Storing data 

6. Decoder 

Section 0.3 - INSIDE THE COMPUTER

1. How many bytes in 24 kilobytes? 

2. What does "RAM" stands for? How is it used in computer systems? 

3. What does "ROM" stands for? How is it used in computer systems? 

4. Why is RAM called "Volatile Memory"? 

5. List the three major components of a computer system 

6. What does "CPU" stand for? Explain its function in a computer. 

7. List the three types of buses found in computer systems and state briefly the purpose of each type of bus. 

8. State which of the following is Unidirectional and bi-directional. a. Data bus b. Address bus 

9. If the address bus for a given computer has 16 lines, what is the maximum amount of memory it can access? 

10. what does "ALU" stand for? what is its purpose? 

11. How are registers used in computer systems? 

12. What is the purpose of the program counter? 

13. What is the purpose of the instruction decoder? 

Answers: 

1. 24,576 

2. Random Access Memory: it is used for temporary storage of programs that the CPU is running, such as the operating system, word processing programs etc... 

3. Read Only Memory: it is used for permanent programs such as those that control the keyboard, mouse etc... 

4. The contnets are RAM are lost when the computer is powered off. 

5. The CPU, Memory and I/O devices 

6. Central Processing Unit: it can be considered as the "brain" of the computer, it executes the programs and controls all other devices in the computer. 

7. The address bus carries the location (address) needed by the CPU: The data bus carries information in and out of the CPU The control bus is used by the CPU to send signals controlling I/O devices. 

8. a. Birectional b. Unidirectional 

9. 64KB or 65,536 bytes 

10. Arithmetic Logic Unit: it performs all arithmetic and logical operations 

11. It is for temporary storage of information 

12. It holds the address of the next instruction to be executed 

13. It tells the CPU what steps to perform for each instruction