Notes, summaries, assignments, exams, and problems for Computers

01. Election Algorithms and Requirements

An election algorithm is a method used in distributed systems to designate a single process as the coordinator or leader. The primary requirements include ensuring that only one leader is elected at a time and that all processes agree on the outcome.

02. Two-Phase Commit Protocol

The Two-Phase Commit (2PC) protocol ensures atomicity and consistency across distributed transactions. It coordinates multiple nodes to ensure they either all commit or all abort.

Phases of 2PC

• Phase 1: The Prepare Phase (Voting): The coordinator asks participants if they can commit.
• Phase 2: The Commit Phase (Decision): The coordinator instructs participants to finalize the transaction based on the votes.

Roles and Steps

• Coordinator:

What is a Data Structure?

A data structure is a specialized format for organizing, processing, retrieving, and storing data. It enables efficient access and modification of data, making it a fundamental concept in computer science and programming. Data structures are essential for managing large amounts of data, supporting various operations such as searching, sorting, insertion, deletion, and traversal.

Classification of Data Structures

Data structures can be broadly classified into two categories: primitive and non-primitive.

1. Primitive Data Structures

These are the basic data types provided by programming languages. They serve as the building blocks for more complex data structures. Examples include:

• Integer
• Float
• Character
• Boolean

2. Non-Primitive

1. What is the Internet?

The Internet is a global communication system connecting millions of computers across the world. It uses the TCP/IP protocol to exchange data, allowing users to access information, communicate, and perform various online activities.

Definition: The Internet is a worldwide network of interconnected computer networks that enables the sharing of information and resources.
History: The Internet originated from ARPANET, developed in 1969 in the USA.

2. Internet Applications

Applications refer to the various ways we utilize the Internet in our daily lives. Key examples include:

• Communication: Facilitates easy, affordable, and fast interaction.
  • Examples: Sending emails, instant messaging (e.g., WhatsApp), and video calls (e.g., Zoom,

1. Keyword

Definition:
A keyword is a reserved word in C language that has a predefined meaning. Keywords cannot be used as names of variables, functions or identifiers.

Examples of Keywords:
int, float, if, else, while, return

Example:

int a = 10;

2. Constant

Definition:
A constant is a value that does not change during the execution of a program.

Types of Constants:

• Integer constant

• Floating constant

• Character constant

Example:

#define PI 3.14

3. Identifier

Definition:
An identifier is the name given to a variable, function or array in a program.

Rules for Identifiers:

• Must start with a letter or underscore

• Should not be a keyword

Example:

int totalMarks;

4. Variable

Definition:
A variable is a memory location used to store data whose value can change during program... Continue reading "It used to define the member functions of a class outside" »

Cache Write Policies

Write-Through

• Definition: Writes data to both the cache and main memory simultaneously.
• Synchronization: Cache and main memory are always synchronized.
• Write Speed: Slower, because every write goes to both cache and memory.
• Data Integrity: Ensures data in both cache and main memory is identical.
• CPU Performance Impact: Slower, due to the additional write to main memory.
• Use Cases: Ideal for systems where data consistency is critical (e.g., databases).
• Cache Miss Handling: Writes to both cache and memory on a miss.
• Complexity: Simple to implement; doesn't require tracking of data in the cache.

Write-Back

• Definition: Writes data to the cache first and only writes to memory when the cache line is evicted.
• Synchronization: Cache and main

What is a Computer Network?

A computer network connects two or more computing devices, such as computers, servers, routers, or switches, through wired or wireless communication channels. This enables efficient sharing of data, resources, and applications.

The primary purpose of a computer network is to facilitate communication and resource sharing among users and devices, whether within a small area like a home or office, or across large geographical regions like the internet.

Advantages of Computer Networks

1. Resource Sharing: Devices like printers, scanners, and internet connections can be shared across the network, reducing hardware costs.
2. Data Sharing: Users can easily share files and data in real-time, improving collaboration and efficiency.
3. Centralized

What Is a Computer?

A computer is an electronic device that accepts input, processes data according to instructions, stores information, and produces output. It operates through both hardware (physical components like CPU, memory, and storage) and software (programs and operating systems).

Definition

A computer is an electronic device that processes information based on a set of instructions, storing, retrieving, and manipulating data to perform a wide range of tasks efficiently.

Key Characteristics

• Speed: Computers perform millions of operations per second.
• Accuracy: High precision in calculations and data processing.
• Automation: Performs tasks automatically once programmed.
• Storage: Can store vast amounts of data and software.
• Versatility: Can execute

Waterfall Model Phases and Deliverables

The Waterfall model follows a sequential process where each phase must be completed before the next begins. Deliverables serve as proof of completion:

• Requirements: Requirements Specification document
• Design: System/architecture design document
• Implementation: Working source code
• Testing: Test report
• Deployment: Live released system
• Maintenance: Bug-fix and update log

Scrum Sprint Plan (2-Week Sprint)

Sprint Goal: Deliver a working login and registration feature.

User Stories:

1. As a user, I can register with email and password.
2. As a user, I can log in.
3. As a user, I can reset my password.

Daily Standup: Every day at 10:00 AM for 15 minutes. The sprint concludes with a review and retrospective.

Kanban Board Structure

Columns:

Parametric Representation of Cubic Curves

Curves are widely used in Computer Graphics for designing smooth shapes, objects, fonts, and animations. A curve can be represented in different ways, and one of the most important methods is the Parametric Representation. In this method, the coordinates of points on the curve are expressed as functions of a parameter t. A Cubic Curve is a curve represented by a third-degree polynomial equation. Parametric representation provides greater flexibility and control over the shape of the curve and is widely used in CAD/CAM systems, animation, and graphical modeling.

Parametric Representation Details

In parametric form, both x and y coordinates are represented as functions of a parameter t:

x = x(t)
y = y(t)

For... Continue reading "Advanced Computer Graphics Algorithms and Curve Modeling" »

🧠 Computer Memory Systems

Computer memory is essential for storing data and instructions. It is measured and organized using specific terminologies and a hierarchical structure.

1. Fundamental Memory Concepts

A. Basic Units of Data Storage

The smallest addressable units of data in a computer are based on the binary system:

B. Storage Locations and Addresses

• Storage