Computer Organization and Architecture Overview

Questions and Answers

What is the primary function of digital computers since their introduction in the 1940s?

Performing numerical computations (correct)

Storing large databases

Performing graphical computations

Executing complex algorithms

What does a binary digit represent in a digital computer?

Bits used in operating systems

The two digits 0 and 1 (correct)

Data stored in kilobytes

A sequence of commands

Which of the following best describes the hardware of a computer system?

Physical electronic components and devices (correct)

Networks connecting multiple machines

Programs designed for end-users

Instructions and data for processing

What is the role of system software in a computer?

To support more effective use of the computer Signup and view all the answers

Why is studying computer organization beneficial for programmers?

It provides insight into hardware management. Signup and view all the answers

What distinguishes application software from system software?

Application software performs specific tasks for end-users. Signup and view all the answers

Which of the following is NOT a characteristic of computer organization?

Focuses exclusively on software design Signup and view all the answers

What is a program defined as in the context of computer systems?

A sequence of instructions for the computer Signup and view all the answers

What is the purpose of an Immediate Operand in an instruction?

It directly specifies the operand value. Signup and view all the answers

In which mode does an instruction specify the address of the operand directly?

Direct Address Signup and view all the answers

What register typically represents the accumulator in a basic computer?

Accumulator (AC) Signup and view all the answers

What characterizes the Indirect Addressing mode?

The instruction provides an address where the actual operand address is stored. Signup and view all the answers

What does the Data Register (DR) do in the context of the Basic Computer?

It stores the operand read from memory. Signup and view all the answers

How does the format of the instruction code in a simple computer typically look?

Two parts: an opcode and an operand address. Signup and view all the answers

What bit length is the Address Register (AR) in the Basic Computer?

12 bits Signup and view all the answers

What happens in a stored program organization?

Instruction and data are stored in the same memory space. Signup and view all the answers

What is the primary focus of computer architecture?

The external structure and behavior of the computer Signup and view all the answers

What does computer organization investigate?

The internal connection and operation of hardware components Signup and view all the answers

Which unit of a computer is responsible for executing instructions?

Control unit Signup and view all the answers

Which of the following components is NOT a part of the basic operational concept in a CPU?

Input unit Signup and view all the answers

What role does the arithmetic-logic unit play in a computer system?

To execute arithmetic and logical operations Signup and view all the answers

Which of the following statements best describes the function of the memory unit?

It stores both data and instructions for processing. Signup and view all the answers

How does the program counter assist in the execution of instructions?

It keeps track of the current and next instruction. Signup and view all the answers

Which of these is a function of the output unit in a computer system?

Transmitting final results to the outside world Signup and view all the answers

What is the primary function of the instruction register (IR)?

To hold the instruction that is currently being executed Signup and view all the answers

Which parts comprise an instruction code?

Opcode and operands Signup and view all the answers

What defines the operation to be performed in an instruction code?

Operation code (Opcode) Signup and view all the answers

How many bits are required for an operation code to define $2^n$ distinct operations?

n bits Signup and view all the answers

What do operands refer to in an instruction code?

The registers or memory addresses involved Signup and view all the answers

Which of the following is NOT a function of the MAR and MDR registers?

Store the currently executing instruction Signup and view all the answers

Which of the following represents a valid operation in an instruction?

SUB AX, BX Signup and view all the answers

What must an instruction code specify in addition to the operation it performs?

The operands or memory words involved Signup and view all the answers

What is the purpose of memory-reference instructions in a computer system?

To specify the micro-operations needed for instruction execution. Signup and view all the answers

What is the main requirement for a computer to serve a useful purpose?

To communicate with the external environment. Signup and view all the answers

In Input-Output configuration, where is the serial information from the keyboard first stored?

Input register INPR Signup and view all the answers

What does the interrupt cycle primarily facilitate?

Branching and saving the return address. Signup and view all the answers

Where is the return address stored during the interrupt cycle in a computer system?

In a fixed location that can be accessed later. Signup and view all the answers

What is the primary function of the control unit in a computer?

To initiate sequences of micro-operations. Signup and view all the answers

What type of information does a terminal unit primarily handle in an input-output configuration?

Serial information Signup and view all the answers

How is the number of micro-operations in a system characterized?

Finite and definable. Signup and view all the answers

Study Notes

Introduction to Computer Organization and Architecture

Digital computers execute various computational tasks using the binary number system, represented through bits (0 & 1).
Information in computers is structured in groups of bits.

Components of a Computer System

Hardware: Physical components and devices making up the system.
Software: Instructions and data processed by the computer. Includes:
- System Software: Essential for effective computer use, including the operating system.
- Application Software: Programs serving specific user tasks.

Importance of Studying Computer Organization

Understanding how programs execute internally can help create more efficient code.
Crucial knowledge for system programmers working closely with hardware.

Computer Architecture vs. Computer Organization

Computer Architecture: External view, focused on structure and behavior, including instruction sets and registers.
Computer Organization: Internal view, concerned with hardware operation and connectivity.

Block Diagram of a Digital Computer

Key units include:
- Input Unit: Receives data and instructions.
- Memory Unit: Stores data and instructions.
- Arithmetic-Logic Unit (ALU): Performs arithmetic and logic operations.
- Control Unit: Fetches and interprets instructions.
- Output Unit: Sends results to the external environment.

Key Registers in CPU

Program Counter (PC): Tracks current and next instruction.
Instruction Register (IR): Holds the presently executing instruction.
Memory Address Register (MAR) and Memory Data Register (MDR): Manage data transfer between memory and CPU.

Instruction Codes and Execution

Instruction Codes: Set of bits directing specific operations performed by the computer.
Consists of an Opcode (operation code) defining the action, and Operands indicating where data resides.

Modes of Instruction

Immediate Mode: Operand included in instruction (e.g., ADD AX, 2387H).
Direct Address Mode: Instruction specifies the operand's address (e.g., MOV AX, [1592H]).
Indirect Address Mode: Instruction mentions an address containing the operand's address (e.g., Load R1, @500).

Stored Program Organization

Simplest computer layout uses a single processor register (Accumulator, AC) with a two-part instruction format.

Registers in Computer Organization

Address Register (AR): Holds address for operands; 12 bits in basic computers.
Data Register (DR): Stores operands fetched from memory.

Memory-Reference Instructions

Clearly defined functions needed for execution of instructions ensuring proper micro-operations.

Input-Output Communication

Essential for practical functionality; example includes terminal units with keyboards and printers.
Input Register (INPR) and Output Register (OUTR) manage serial data transfer.

Interrupt Cycle

A mechanism allowing hardware to pause the current process and resume later, storing the return address for later continuation.

Control Unit Functions

Initiates sequences of micro-operations; finite number involved in overall system operations.

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Description

This quiz covers the basics of computer organization and architecture, focusing on digital computers and their operational principles. Explore the block diagram and definitions that form the foundation of computing systems. Ideal for students looking to understand the structural design of digital computers.