Computer Fundamentals & Networks – Quick-Review Notes

Computer Fundamentals

• Computer = electronic data processor; derives from “compute” (to calculate)
• Data processing cycle: capture → manipulate → output; $\text{Data (input)} \rightarrow \text{Information (output)}$

Key Characteristics

• Automatic, high $\text{speed (}\mu\text{s, ns, ps)}$, high accuracy (GIGO if bad input)
• Diligence, versatility, large memory, power of remembering
• Lacks $\text{I.Q.}$ and feelings

Computer Generations (H/W trend)

• 1st Vacuum tubes → 2nd Transistors → 3rd IC (SSI/MSI) → 4th VLSI / microprocessor → 5th ULSI + Internet

Basic Organization

• CPU = ALU + CU; interfaces with primary & secondary storage, input, output
• Five basic operations: input, store, process, output, control

Memory/Storage

• Primary: RAM (volatile, fast, small, $\text{SIMM}$ expand) & Cache (very fast buffer)
• ROM: non-volatile, read-only (e.g., boot code)
• Secondary: magnetic disks/tapes, optical disks, flash; non-volatile, high capacity, slow

Input / Output Devices

• Input: keyboard, mouse, scanner, mic, camera, biometric, etc.
• Output: monitor, printer, plotter, projector, speakers, headphones

Computer Types

• By data: Analog, Digital, Hybrid
• By size/power: Super > Mainframe > Mini > Micro (PC: desktop, laptop, palmtop) > Workstation

Website & Game Categories (overview)

• Websites: e-commerce, business, portfolio, event, personal, membership, blog, info, etc. (≈ $\text{25+}$ variants)
• Games: action, adventure, RPG, simulation, strategy, sports, racing, puzzle, fighting, shooter, platform, horror, idle, educational

Computer Networks

• Network = interconnection of $\ge 2$ computers via communication links (copper, radio, etc.)
• Enables client/server model, file/resource sharing, communication, flexible access

Network Sizes

• LAN: up to few km, private, $10$–$100\,\text{Mbps}$, common topologies Star/Bus/Ring; WLAN = wireless LAN
• MAN: spans a city (≈ $30$–$50\,\text{km}$); e.g., cable TV
• WAN: spans countries/world; uses public/leased links; Internet = global WAN

Topologies & Core Points

• Star: nodes ↔ hub; easy manage; hub failure critical
• Bus: single backbone; cheap; heavy traffic degrades
• Ring: loop; longer reach; single node failure affects all
• Mesh: many links; high reliability; costly
• Tree: stars linked; scalable; hub dependence

Key Protocols

• TCP: reliable, packetizes & reassembles data
• IP: addressing & routing packets
• TCP/IP = universal Internet stack
• FTP: file transfer (client/server)
• HTTP: web data exchange; HTTPS = HTTP over SSL for secure content

Networking Hardware

• Hub: multi-port signal splitter
• Repeater: amplifies signals
• Bridge: links similar LANs
• Router: connects multiple networks, routes packets
• Gateway: converts between different protocols/networks