Logiacal Organization of Computer 1
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, Logiacal Organization of Computer 2
Introduction
The logical organization of a computer refers to the way its various components and subsystems are designed and
interconnected to perform computational tasks. Here are the key components and their logical organization:
1. Central Processing Unit (CPU): The CPU is the brain of the computer and performs most of the processing tasks. It
consists of the Arithmetic Logic Unit (ALU) for performing mathematical and logical operations and the Control Unit (CU)
for coordinating the execution of instructions.
2. Memory: Computers have different types of memory used for storing data and instructions. The main types are:
- Random Access Memory (RAM): It provides temporary storage for data and instructions that the CPU needs to access
quickly. RAM is volatile, meaning its contents are lost when the computer is powered off.
- Read-Only Memory (ROM): It contains firmware or permanent instructions that are typically stored by the
manufacturer. The instructions stored in ROM are non-volatile, meaning they are retained even when the power is off.
- Cache Memory: It is a small, high-speed memory that stores frequently accessed data to reduce the time it takes for
the CPU to retrieve information from main memory.
3. Input/Output (I/O) Devices: These devices allow the computer to interact with the external world. Common I/O devices
include keyboards, mice, displays, printers, scanners, and storage devices like hard drives and solid-state drives. They are
connected to the CPU and memory via buses, such as the Universal Serial Bus (USB) or SATA.
4. System Bus: The system bus is a communication pathway that allows different components of the computer to
exchange data and control signals. It consists of multiple buses, including the address bus, data bus, and control bus. The
address bus carries memory addresses, the data bus carries data between components, and the control bus carries control
signals to coordinate operations.
5. Operating System (OS): The OS is a software layer that manages and controls the computer's hardware and software
resources. It provides an interface between the user and the computer and handles tasks such as memory management,
process scheduling, file management, and device management.
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, Logiacal Organization of Computer 3
6. Instruction Set Architecture (ISA): The ISA defines the set of instructions that the CPU can execute and the memory
organization visible to the software. It serves as an interface between the hardware and software, enabling compatibility
and portability of software across different computer systems.
These components work together following a logical organization to execute instructions, store and retrieve data, and
facilitate communication between different parts of the computer system. The specific details of the logical organization
may vary depending on the computer architecture and design.
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, Logiacal Organization of Computer 4
Chapter 1: Number System
What is number system?
In computer systems, numbers are represented using different number systems or bases. A number system is a mathematical
notation that represents numbers using symbols or digits. It provides a systematic way to express and manipulate numerical
quantities. Different number systems use different sets of symbols and rules for representing numbers.
These number systems provide different representations for numbers and have specific use cases. Converting numbers between
different number systems involves applying mathematical algorithms or using built-in functions in programming languages.
Type of number system
There are two types of number systems:
(1) Positional number system
(2) Non-positional number system
Positional number system
A positional number system is a mathematical notation that represents numbers using digits or symbols, where the value of
each digit depends on its position within the number. The position of a digit determines its weight or place value, which
contributes to the overall value of the number. The most commonly used positional number system is the decimal system, also
known as the base-10 system. In the decimal system, there are ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Each digit's position
represents a power of 10. For example, in the decimal number 4567, the digit 4 represents 4 × 10^3 (4,000), the digit 5
represents 5 × 10^2 (500), the digit 6 represents 6 × 10^1 (60), and the digit 7 represents 7 × 10^0 (7). The value of the entire
number is obtained by adding these individual contributions.
Positional number systems provide a flexible and compact representation of numbers, allowing for easy arithmetic operations
and efficient storage of numerical data. They are extensively used in everyday calculations, computer programming, and digital
systems.
Non-positional number system
In addition to the positional number systems mentioned earlier (such as decimal, binary, hexadecimal, and octal), there is
another type of number system called a non-positional number system.
Non-positional number systems are based on the concept of assigning values to individual symbols without considering their
positions within the number. These systems do not rely on positional notation, where the value of a symbol depends on its
position relative to other symbols. One example of a non-positional number system is the unary number system. In the unary
system, numbers are represented using only a single symbol, typically a tally mark or a repeated symbol. Each symbol represents
a fixed value, and the number is determined by counting the total number of symbols.
For example, in the unary system, the number 4 is represented by four tally marks or four repeated symbols, such as "||||". The
number 7 would be represented by seven tally marks or seven repeated symbols, such as "|||||||".
XCoode
XCoode
, Logiacal Organization of Computer 2
Introduction
The logical organization of a computer refers to the way its various components and subsystems are designed and
interconnected to perform computational tasks. Here are the key components and their logical organization:
1. Central Processing Unit (CPU): The CPU is the brain of the computer and performs most of the processing tasks. It
consists of the Arithmetic Logic Unit (ALU) for performing mathematical and logical operations and the Control Unit (CU)
for coordinating the execution of instructions.
2. Memory: Computers have different types of memory used for storing data and instructions. The main types are:
- Random Access Memory (RAM): It provides temporary storage for data and instructions that the CPU needs to access
quickly. RAM is volatile, meaning its contents are lost when the computer is powered off.
- Read-Only Memory (ROM): It contains firmware or permanent instructions that are typically stored by the
manufacturer. The instructions stored in ROM are non-volatile, meaning they are retained even when the power is off.
- Cache Memory: It is a small, high-speed memory that stores frequently accessed data to reduce the time it takes for
the CPU to retrieve information from main memory.
3. Input/Output (I/O) Devices: These devices allow the computer to interact with the external world. Common I/O devices
include keyboards, mice, displays, printers, scanners, and storage devices like hard drives and solid-state drives. They are
connected to the CPU and memory via buses, such as the Universal Serial Bus (USB) or SATA.
4. System Bus: The system bus is a communication pathway that allows different components of the computer to
exchange data and control signals. It consists of multiple buses, including the address bus, data bus, and control bus. The
address bus carries memory addresses, the data bus carries data between components, and the control bus carries control
signals to coordinate operations.
5. Operating System (OS): The OS is a software layer that manages and controls the computer's hardware and software
resources. It provides an interface between the user and the computer and handles tasks such as memory management,
process scheduling, file management, and device management.
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, Logiacal Organization of Computer 3
6. Instruction Set Architecture (ISA): The ISA defines the set of instructions that the CPU can execute and the memory
organization visible to the software. It serves as an interface between the hardware and software, enabling compatibility
and portability of software across different computer systems.
These components work together following a logical organization to execute instructions, store and retrieve data, and
facilitate communication between different parts of the computer system. The specific details of the logical organization
may vary depending on the computer architecture and design.
XCoode
, Logiacal Organization of Computer 4
Chapter 1: Number System
What is number system?
In computer systems, numbers are represented using different number systems or bases. A number system is a mathematical
notation that represents numbers using symbols or digits. It provides a systematic way to express and manipulate numerical
quantities. Different number systems use different sets of symbols and rules for representing numbers.
These number systems provide different representations for numbers and have specific use cases. Converting numbers between
different number systems involves applying mathematical algorithms or using built-in functions in programming languages.
Type of number system
There are two types of number systems:
(1) Positional number system
(2) Non-positional number system
Positional number system
A positional number system is a mathematical notation that represents numbers using digits or symbols, where the value of
each digit depends on its position within the number. The position of a digit determines its weight or place value, which
contributes to the overall value of the number. The most commonly used positional number system is the decimal system, also
known as the base-10 system. In the decimal system, there are ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Each digit's position
represents a power of 10. For example, in the decimal number 4567, the digit 4 represents 4 × 10^3 (4,000), the digit 5
represents 5 × 10^2 (500), the digit 6 represents 6 × 10^1 (60), and the digit 7 represents 7 × 10^0 (7). The value of the entire
number is obtained by adding these individual contributions.
Positional number systems provide a flexible and compact representation of numbers, allowing for easy arithmetic operations
and efficient storage of numerical data. They are extensively used in everyday calculations, computer programming, and digital
systems.
Non-positional number system
In addition to the positional number systems mentioned earlier (such as decimal, binary, hexadecimal, and octal), there is
another type of number system called a non-positional number system.
Non-positional number systems are based on the concept of assigning values to individual symbols without considering their
positions within the number. These systems do not rely on positional notation, where the value of a symbol depends on its
position relative to other symbols. One example of a non-positional number system is the unary number system. In the unary
system, numbers are represented using only a single symbol, typically a tally mark or a repeated symbol. Each symbol represents
a fixed value, and the number is determined by counting the total number of symbols.
For example, in the unary system, the number 4 is represented by four tally marks or four repeated symbols, such as "||||". The
number 7 would be represented by seven tally marks or seven repeated symbols, such as "|||||||".
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