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Unit 1: Fundamentals of Computer

CAP1007 — Fundamentals Of Information Technology 5 min read

A computer is an electronic device that accepts data as input, processes it according to stored instructions, and produces meaningful information as output. This unit establishes what defines a computer, how the machine evolved, how its parts fit together, where it is applied, and how it internally represents data through number systems.

  • Data vs information: Data is raw, unprocessed facts (e.g. 85); information is processed, meaningful output (e.g. "score = 85%").
  • Stored-program concept: Both instructions and data reside in memory, the basis of every modern computer (von Neumann, 1945).
  • Digital operation: Computers work on discrete binary states, 0 and 1, corresponding to OFF and ON voltage levels.
  • Program: A finite sequence of instructions directing the hardware to perform a task.

II. Characteristics of Computers

Defining traits that make computers indispensable

A computer's usefulness rests on a fixed set of operational qualities that hold across all machines regardless of size.

  • Speed: Operations are measured in microseconds (10⁻⁶), nanoseconds (10⁻⁹), and picoseconds (10⁻¹²); a computer performs millions of instructions per second (MIPS).
  • Accuracy: Output is error-free provided input and logic are correct; mistakes arise from bad data, summarised as GIGO (Garbage In, Garbage Out).
  • Diligence: Free from fatigue or boredom, it performs the millionth calculation with the same precision as the first.
  • Versatility: The same machine can prepare a payroll, edit a video, and run a simulation by loading different programs.
  • Storage capacity: Vast volumes of data are held in secondary memory and retrieved on demand, measured in KB, MB, GB, and TB.
  • Automation: Once a program starts, the computer proceeds through the task without human intervention.
  • Limitations: No intelligence or intuition of its own (IQ = 0); it cannot decide or correct itself unless programmed to.

III. Generation of Computers

The five technological eras of computing

Each generation is defined by the primary electronic switching component it used, which determined its size, speed, and cost.

A. First Generation (1946–1959) — Vacuum Tubes

  • Technology: Vacuum tubes for circuitry, magnetic drums for memory.
  • Traits: Very large, consumed heavy power, generated great heat, unreliable.
  • Language: Machine language (binary) only.
  • Examples: ENIAC, UNIVAC, EDVAC.

B. Second Generation (1959–1965) — Transistors

  • Technology: Transistors replaced tubes; smaller, faster, more reliable.
  • Language: Assembly language and early high-level languages (FORTRAN, COBOL).
  • Examples: IBM 1401, IBM 7094.

C. Third Generation (1965–1971) — Integrated Circuits

  • Technology: ICs packing many transistors on a silicon chip; keyboards and monitors introduced.
  • Traits: Cheaper, smaller, supported multiprogramming.
  • Examples: IBM 360, PDP-8.

D. Fourth Generation (1971–1980) — Microprocessors

  • Technology: VLSI (Very Large Scale Integration) placed the entire CPU on one chip (the microprocessor).
  • Traits: Rise of the personal computer, GUIs, and networks.
  • Examples: Intel 4004, IBM PC, Apple II.

E. Fifth Generation (1980–present) — Artificial Intelligence

  • Technology: ULSI (Ultra Large Scale Integration), parallel processing, AI.
  • Traits: Natural-language processing, machine learning, voice recognition.
  • Examples: Modern laptops, supercomputers, AI systems.

IV. Block Diagram of a Computer

The functional units and their data flow

Every computer follows the same logical model: input is captured, processed by the CPU under control of instructions, and delivered as output, with memory holding both.

TEXT
   INPUT  --->  +-----------------------+  --->  OUTPUT
   UNIT         |         CPU           |        UNIT
                |  +-----+   +-------+  |
                |  | ALU |   | CU    |  |
                |  +-----+   +-------+  |
                +-----------|-----------+
                            |
                     +-------------+
                     |   MEMORY    |
                     +-------------+
   (solid path = data flow, control unit directs all units)

A. Input Unit

  • Function: Accepts data and instructions from the user and converts them to binary for the machine.
  • Devices: Keyboard, mouse, scanner, microphone.

B. Central Processing Unit (CPU)

The CPU is the "brain" that executes instructions; it has three parts.

  • Arithmetic and Logic Unit (ALU): Performs arithmetic (+, −, ×, ÷) and logical comparisons (<, >, =).
  • Control Unit (CU): Directs and coordinates all operations by issuing timing and control signals; fetches, decodes, and executes instructions.
  • Registers: Small, fast storage inside the CPU holding data currently being processed (e.g. accumulator, program counter).

C. Memory Unit

  • Primary memory: Directly accessible by the CPU; RAM (volatile, working memory) and ROM (non-volatile, holds startup firmware).
  • Secondary memory: Permanent storage for later use — hard disk, SSD, pen drive.

D. Output Unit

  • Function: Converts binary results back into human-readable form.
  • Devices: Monitor, printer, speaker.

V. Application of Computers in Various Sectors

Domains transformed by computing

Computers apply their speed and storage across nearly every field of work.

  • Education: E-learning, online exams, digital libraries, simulations for concepts hard to demonstrate physically.
  • Banking: ATMs, core banking, online transfers, fraud detection, RTGS/NEFT settlement.
  • Healthcare: Patient records (EHR), CT/MRI imaging, robotic surgery, diagnostic software.
  • Business: Inventory control, payroll, billing, data analytics, e-commerce platforms.
  • Government: e-Governance, digital identity (e.g. Aadhaar-style databases), tax filing, land records.
  • Industry: CAD/CAM design, robotic assembly lines, process control (SCADA).
  • Entertainment: Gaming, animation, video/audio editing, streaming.
  • Science and research: Weather forecasting, space simulation, molecular modelling on supercomputers.

VI. Data Representation Using Number System

How computers encode all data as numbers

Internally a computer stores everything — text, images, sound — as binary numbers, so understanding number systems explains its memory.

A. Units of Data

  • Bit: The smallest unit, a single binary digit (0 or 1).
  • Byte: 8 bits, the standard unit for one character; 1 KB = 1024 bytes, 1 MB = 1024 KB.

B. Positional Number Systems

Each system has a base (radix) = the number of distinct digits, and each digit carries a weight equal to base raised to its position.

  • Decimal (base 10): Digits 0–9; used by humans. Example: 345 = 3×10² + 4×10¹ + 5×10⁰.
  • Binary (base 2): Digits 0,1; the machine's native system.
  • Octal (base 8): Digits 0–7; a compact shorthand for binary (3 bits per digit).
  • Hexadecimal (base 16): Digits 0–9 and A–F (A=10 … F=15); 4 bits per digit, us
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