Computer Architecture - Short Questions and Answers

Computer Architecture - Short Questions and Answers. Find the most important and more conceptual questions with answers of Computer, ICS Part 1 Chapter No.5: Computer Architecture, for the interview and final exams and entry test for admission in universities.

Chapter No.5 
Computer Architecture

Short Questions & Answers

Q.1: What is Von Neumann architecture?

Answer:

In 1951, John Von Neumann proposed an internal design of an electronic computer. This design is called Von Neumann architecture. The computer-based on this architecture is called stored-program machine. The computer reads the instructions one by one and executes them accordingly. This was a simple design. But it proved very powerful.

 

Q.2: What are the most important components of a modern stored-program machine?

Answer:

The most important components of a stored program machine include:

• Processor (CPU)
• Main Memory
• I/O Unit
• Bus Interconnection

 

Q.3: What is the processor?

Answer:

The processor, also called the Central Processing Unit (CPU), executes instructions that operate the computer. It contains Control Unit (CU), Arithmetic Logic Unit (ALU), and registers.

 

Q.4: Differentiate between Control Unit (CU) and Arithmetic Logic Unit (ALU)?

Answer:

Control Unit (CU): CU reads instructions from the memory. It decodes each instruction and uses other components of the computer system to execute these instructions.

Arithmetic Logic Unit (ALU): ALU performs arithmetic (+, -, `\times`, `\div`) comparison (<, >, <=, >=, !=) and logic operations (AND, OR, NOT).

 

Q.5: What is the main memory?

Answer:

Main memory consists of electronic components that store instructions which are executed by the processor and the data needed by these instructions. Since computer system works with data and instructions by storing them in the main memory, it is also known as the working area of the computer.

 

Q.6: What is Bus Interconnection OR Bus?

Answer:

Bus interconnection is the communication channel that allows various components of the computer system to communicate with each other. It is used to connect the main components of a computer. General-purpose computers have a 70-100 line system bus.

 

Q.7: What is I/O Unit?

Answer:

The input/output unit handles the processor’s communication with its peripherals. It controls the flow of data to and from the processor. It also controls external devices such as disc drives, monitors, printers, etc.

 

Q.7: What is a RAM?

Answer:

RAM (Random Access Memory) is the main memory of the computer system. It is called Random Access because data can be read or written at any place in it. RAM holds programs and data that are being currently executed when the computer is turned on.

 

Q.8: Why RAM (Main Memory) is called Random Access Memory?

Answer:

CPU or any other component of the computer can access any byte from the main memory by specifying its address. Different bytes of the main memory can be accessed directly at random, the memory is built from electronic components so accessing any part of the memory takes an equal amount of time. So the main memory is Random Access Memory.

 

Q.9: Define DRAM?

Answer:

DRAM (Dynamic Random Access Memory) stores data in the form of an electric charge. In order to maintain data in the DRAM, the chip is recharged or refreshed frequently. During the refreshing process, the processor of the computer cannot access the DRAM. The refreshing process thus decreases the processing speed of the computer. This memory was used in old microcomputers and less expensive.

 

Q.10: Define SRAM?

Answer:

In SRAM (Static Random Access Memory) technology, memory cells are made from digital gates. These gates can hold data without any need for frequent refreshing. As no refreshing is required to SRAM, these chips are faster than the DRAM and more expensive. This memory is known as cache memory.

 

Q.11: What is the cache memory?

Answer:

Cache memory usually has a very small size as compared to the main memory in the computer but plays a very important role in increasing the performance of a computer system. It is used for speeding up the data transfer operations of the CPU.

 

Q.12: What is ROM?

Answer:

ROM (Read Only Memory) is a type of internal memory that normally can only be read. It is used in computer systems to hold information that is either permanent or does not change frequently. BIOS instructions are provided on a ROM chip. When power is turned on, the computer uses BIOS instructions to boot the system.

 

Q.13: What is BIOS or Firmware?

Answer:

BIOS (Basic Input-Output System) or firmware are the instructions which are stored in ROM. These are used to boot the computer system when it is turned on.

 

Q.14: What is PROM?

Answer:

PROM (Programmable Read-Only Memory) is initially blank and the user or manufacturer can write data onto it by using special devices. Once the program/data is written (burned) onto PROM, it cannot be erased or changed.

 

Q.15: What is EPROM?

Answer:

EPROM (Erasable Programmable Read-Only Memory) is similar to PROM but it can be erased and reprogrammed (burned) by the user or manufacturer by using special devices. Unlike PROM, the data written on it can be erased by using ultraviolet rays.

 

Q.16: What is EEPROM?

Answer:

EEPROM (Electrically Erasable Programmable Read-Only Memory) is similar to EPROM but it is much easier to erase and reprogram by using electrical devices.

 

Q.17: What is data bus?

Answer:

The lines that are used to carry data between the microprocessor and the main memory are called data buses. It consists of 8, 16, 32, or 64 lines. Data bus is a bi-directional bus. It is used to exchange data between processors and other units of computers e.g., memory, input/output unit.

 

Q.18: What is the address bus?

Answer:

When a computer component wants to communicate with another, it uses a few of the system bus lines to specify the destination component by using its address. These lines are known as the address bus. It is a unidirectional bus, i.e., it carries information only in one direction.

 

Q.19: What is control bus?

Answer:

These lines are used to transmit different commands from one component to the other. For example, if the CPU wants to read data from the main memory; it will use the control bus to send the memory read command to the main memory of the computer. This is also used to transmit other control signals lime ACKS (Acknowledgement signals).

 

Q.20: Differentiate between the system bus and expansion bus?

Answer:

The system bus connects the processor with main memory and other devices whereas expansion bus allows the processor to communicate with the peripheral devices connected to the computer.

 

Q.21: Differentiate between bus grant and bus request commands?

Answer:

Bus grant command is used by the bus controller to indicate the grant of the bus to a device whereas the bus request command is used to request for control on the bus so that the requesting device can use it to transmit data.

 

Q.22: What is interrupt?

Answer:

In this scheme, the processor issues the command to the I/O devices. When the devices get ready, they generate an interrupt signal for the processor. On sensing this signal, the processor suspends all other processing and performs the I/O operation. The disadvantage of this scheme is that it reduces the overall performance of the processor.

 

Q.23: What is DMA?

Answer:

In DMA (Direct Memory Access) scheme data transfer between I/O device and main memory takes place without the intervention of the CPU. Whenever the CPU wants to transfer data, it instructs the I/O unit of the data to be transferred. The advantage of this scheme is that it increases the overall performance of the processor.

 

Q.24: What is a CPU register?

Answer:

The CPU needs high-speed storage areas where the data can be stored temporarily. As these storage areas are used frequently, so for efficiency these special-purpose storage areas are provided within the CPU for enhancing the performance of the CPU. These special-purpose storage areas are called CPU registers.

 

Q.25: Define special purpose registers?

Answer:

These registers are usually used only by the CPU. These are normally not used by users. Special purpose registers include:

• Program Counter (PC)
• IR (Instruction Register)
• MAR (Memory Address Register)
• MBR (Memory Buffer Register)
• Stack Pointer

 

Q.26: Define general-purpose registers?

Answer:

General-purpose registers can be used for more than one purpose. General-purpose registers can be used as either a data register or an address register. These include:

• AX (Accumulator Register)
• BX (Base Register)
• CX (Counter Register)
• DX (Data Register)

 

Q.27: Define segment registers?

Answer:

These registers are used for manipulating blocks (segments) of the main memory. Segment registers include:

• CS (Code Segment)
• DS (Data Segment)
• ES (Extra Segment)
• SS (Stack Segment)

 

Q.28: What is PC register?

Answer:

PC (Program Counter) holds the address of the next instruction to be fetched for execution. As soon this instruction is fetched, its value is incremented so that it still has the address of the next instruction.

 

Q.29: What is IR register?

Answer:

IR stands for Instruction Register. Once the instruction is fetched it is stored in the IR where this instruction is decoded.

 

Q.30: What is MAR register?

Answer:

MAR stands for Memory Address Register. When the CPU wants to store some data in the memory or reads the data from the memory, it places the address of the required memory location in the MAR.

 

Q.31: What is MBR register?

Answer:

MBR stands for Memory Buffer Register. The CPU uses this register to store data coming from the memory or going to the memory.

 

Q.32: What is the stack pointer?

Answer:

Stack pointer register points to the program stack. A stack is a set of memory locations in the main memory in which data is stored and retrieved in order. The data is stored and retrieved in Last In First Out (LIFO) order.

 

Q.33: Define the following:

Accumulator Register (AX)

Base Register (BX)

Counter Register (CX)

Data Register (DX)

 Answer:

Accumulator Register (AX) is used for arithmetic and data operations.

Base Register (BX) is used for arithmetic and data movement and special addressing abilities.

Counter Register (CX) is used for counting purpose. This acts as a counter for repeating or looping.

Data Register (DX) has a special role in division and multiplication.

 

Q.34: Define the following terms:

Code Segment (CS)

Data Segment (DS)

Extra Segment (ES)

Stack Segment (SS)

Answer:

Code Segment (CS): The CS register holds the base location of all executable instructions (code) in the program. It is a 16-bit register containing the address of the segment with processor instructions.

Data Segment (DS): The DS register is the default base location for memory variables. The CPU calculates the offsets of variables using the current value of DS. It is a 16-bit register containing the address of the segment with program data.

Extra Segment (ES): The ES register is an additional base location for the memory variables. It is a 16-bit register containing the address of the segment, usually with program data.

Stack Segment (SS): The SS register contains the base location of the current program stack. It is a 16-bit register containing the address of the segment with the program stack.

 

Q.35: What is instruction set of CPU?

Answer:

A processor can execute only a small number of basic instructions. These instructions are called the instruction set of the CPU. CPU performs all operations by combining these basic instructions. Different CPUs have different instruction sets. Usually a modern CPU’s instruction set consists of 80 to 120 instructions.

 

Q.36: What are the three address instruction formats?

Answer:

Computer with three-address instruction formats can use each address field to specify either a processor register or memory operand.

The advantage of this format is that it results in short. The disadvantage is that the binary-coded instructions require too many bits to specify three addresses.

 

Q.37: What is meant by decodes?

Answer:

Control Unit (CU) figures out what the instruction is and what signals should be generated and what circuits should be activated to carry out the instruction.

 

Q.38: What is operating system?

Answer:

An operating system is a set of programs that run in the background on the computer and provide an environment in which other programs can be executed and the computer system can be used efficiently.

 

Q.39: What is memory management?

Answer:

The OS manages the main memory. When several programs execute simultaneously, the OS manages and allocates memory to these programs.

 

Q.40: What is scheduling?

Answer:

A computer can run several programs simultaneously. The OS schedules these programs in various areas of the computer so that different parts of different programs can be worked on at the same time.

 

Q.41: What is the user interface?

Answer:

Computer users interact with software through its user interface. It controls how data and instructions are entered and information is presented on the screen. It is through the user interface of an OS that the user communicates with the computer.

 

Q.42: Differentiate between GUI and command prompt (CLI)?

Answer:

Command Prompt – CLI (Command Line Interface): With a CLI, the instructions are given to the computer by typing keywords such as COPY or DELETE or by pressing special keys on the keyboard. A set of commands are used to interact with the computer. An example of a CLI operating system is DOS.

 

Graphical User Interface (GUI): GUI operating system uses menus and visual images such as icons, buttons, and other graphical objects to give commands. GUI is the easiest to lean and work. Example of GUI operating system is MS Windows and Linux.

 

Q.43: Differentiate between compiler and interpreter?

Answer:

Both are high-level language translators. The compiler scans the entire program and translates the whole program into machine code at once. The interpreter translates just one statement of the program at a time into machine code. Clearly, if an instruction has some error an interpreter can easily identify it.

 

Q.44: Differentiate between source code and object code?

Answer:

The high-level language version of the program is usually called the source code and the resulting machine code program is called the object code.

 

Q.45: What is an assembler?

Answer:

An assembler is a language translator of assembly language that produces the binary instruction for a given assembly language program.

➤ Security Copyright and the Law - MCQs
➤ Computer Architecture - MCQs
➤ Applications and Uses of Computer - Short Questions
➤ Applications and Uses of Computer - MCQs Set-1
➤ Applications and Uses of Computer - MCQs Set-2
➤ Data Communication - MCQs 
➤ Data Communication - Short Questions
➤ Information Networks - Short Questions
➤ Information Networks - MCQs