RL

The Ever-Changing Computers

📚 Reviewer: The Everchanging Computers

1. What is a Computer?

  • A computer is a programmable machine that processes, stores, and retrieves data based on instructions from software.

  • Basically, it’s not just for “typing” or “gaming”—it transforms the modern world into a global village (kasi everything is connected).

2. History of Computers

  • “Computer” originally = a person who calculated manually. Later naging machine.

  • 1940s–1950s: First digital computers = giant machines with vacuum tubes. Imagine isang buong room, pero yung power mas mababa pa sa smartphones ngayon.

  • Two types:

    • Digital Computers → binary (0s & 1s), step-by-step data processing.

    • Analog Computers → represent data as physical values (like voltage). More “continuous” than digital.

3. Analog Computers (OG style)

  • James Thomson & Lord Kelvin → created mechanical devices to solve equations (like tide predictors).

  • Vannevar Bush → built the Differential Analyzer (1930s). Para siyang huge machine with gears and motors for solving equations.

  • Downside: noisy, less accurate, phased out after WWII.

4. Digital Computers (Generations)

🔴 First Generation (1940s–1950s)

  • Vacuum tubes = main tech.

  • Examples: ENIAC, UNIVAC I, IBM 701.

  • Problem: Sobrang laki, sobrang init, mabilis masira.

🟠 Second Generation (1950s–1960s)

  • Transistors replace vacuum tubes.

  • Smaller, faster, cheaper, mas reliable.

  • Example: Manchester University’s transistor computer.

🟡 Third Generation (1960s)

  • Integrated Circuits (ICs) invented by Jack Kilby.

  • Transistors combined on a small chip = faster & more efficient.

  • May keyboards + monitors na, plus operating system → multitasking begins!

🟢 Fourth Generation (1970s–present)

  • Microprocessors (Intel 4004, 1969).

  • One tiny chip = CPU + memory + input/output control.

  • Basis ng mga modern-day PCs, laptops, phones.

5. Key Components of Computers

  • Input Unit → Gets data from user (keyboard, mouse, scanner).

  • CPU (Brain of Computer):

    • Memory Unit → stores data & instructions.

    • Control Unit → interprets commands & directs flow.

    • ALU (Arithmetic Logic Unit) → does math & logic.

  • Output Unit → Shows results (monitor, printer, speakers).

6. Operating System (OS)

  • Software that manages hardware & makes it usable.

  • Functions: abstraction (hide hardware details), execute programs, user-friendly interface.

  • Pros: Makes computers usable, efficient, accessible.

  • Cons: Can lose data (volatile), expensive, not always secure.

Examples of OS:

  • Windows → dominates PC/laptop market (since 1985).

  • MacOS → Apple’s OS for Mac computers.

  • Android → mobile OS by Google, most used worldwide.

  • iOS → Apple’s mobile OS (since 2007), known for stability & design.

✅ Summary Tip: Computers evolved from giant noisy machines to tiny powerful chips. The big leap every generation was about making them smaller, faster, cheaper, and more reliable. OS makes everything user-friendly so we can use computers in daily life.