Networking, HTTP, Software Engineering, Testing, and Version Control Concepts for CS Students

Server-Client Model

Communication between client (browser) and server (web server); typically request-response loop.

IP Protocol

Responsible for addressing, routing, and delivering packets across networks.

Application Layer Protocol

Protocols used by applications, e.g., HTTP, FTP, DNS.

Top Level Domain (TLD)

The most general level of a domain name.

Second/Third Level Domain

More specific hierarchy in domain names.

Recursive DNS Server

Works like 'yellow pages' to find IP addresses from domain names.

URL Fragment

#fragment allows navigation to a specific section of a webpage.

Connectionless

Client disconnects after each request.

Stateless

Each request is independent; server does not store state between requests.

GET Request

Retrieves resource content.

HEAD Request

Retrieves headers only, without content.

Project Attributes

Temporary, requires resources, unique purpose.

Uncertainty in Projects

Highest at project start, decreases over time.

Waterfall Model

Best when technology is well-understood and project is short.

Logic Errors

Incorrect reasoning that produces wrong results; not detected by compiler.

Run-Time Errors

Can be caused by logic errors.

Unit Testing

Tests individual functions/classes/modules.

Integration Testing

Tests interactions/interfaces between modules. Incremental integration possible.

System Testing

Tests full system; includes functional and non-functional requirements (performance, reliability).

Acceptance Testing

Alpha/beta testing by users for approval.

Black-Box Testing

Tests functionality without internal code knowledge; focuses on input/output.

White-Box Testing

Tests internal logic, every line of code, structure, and paths.

Version Control

Managing multiple versions of code/documents.

Centralized Systems

CVS, Subversion; single main repository.

Distributed Systems

Git, Mercurial; every repository is full.

Git Advantages

Efficient, industry standard, supports collaboration, allows 'time machine' functionality.

Typical Git Workflow

1. git pull → update local repo from remote 2. Edit files 3. git add → stage changes 4. git commit -m 'message' → commit changes locally 5. git push → send changes to remote repository.

Requirement Analysis

Understand what users and stakeholders need.

Functional Design

Decide what functions/features the system must have.

High-Level Design

Break system into modules or components.

Detailed Design

Define code architecture, skeleton, and documentation.