Computer Definition, Data Processing, Data vs Information

Computer Definition and Capabilities

• A computer is a tool or machine used for data processing to produce information.
• Input: Takes data via keyboard and input units.
• Storage: Stores data on diskettes, hard disks, or other mediums.
• Processing: Processes data using the Central Processing Unit (CPU).
• Output: Displays results on the screen or Visual Display Unit (VDU).

Data vs. Information

• Data consists of raw facts about a person, object, or place (e.g., name, age, height).
• Information is processed data or a meaningful statement (e.g., net pay, exam results).

Methods of Data Processing

• Manual: Uses tools like chalk, pens, and pencils, is cumbersome, slow, and prone to errors and does not allow for processing of large volumes of data on a regular and timely basis.
• Mechanical: Uses machines like typewriters and adding machines but is routine, noisy, hazardous, and does not allow for processing of large volumes of data continuously and timely.
• Computer: Allows steady, continuous processing with error correction with neat outputs, enhanced accuracy, and reliability

Computer Characteristics

• Speed: Processes large amounts of data quickly.
• Accuracy: High accuracy, with errors mainly due to human factors, and includes error-detecting.
• Storage: Has internal and external storage, measured in Kilo (K) modules where K=1024 memory locations.
• Automatic: Runs programs automatically once in memory.
• Reliability: Consistent performance without tiredness.
• Flexibility: Performs various tasks reduced to logical steps, including online, multiprogramming, and real-time processing.

Computing System Components

• Computing system: Composed of the computer system, user, and operating environment.
• Computer system: Made up of hardware and software.
• Hardware: Includes input, processing, and output units.
• Input unit: Feeds data into the computer (e.g., keyboard, mouse, scanner).
• Processing unit: Comprises the Arithmetic and Logic Unit (ALU), control unit, and main memory.
• Main memory: The primary memory has Read Only Memory (ROM) for permanent instructions and Random Access Memory (RAM) for temporary data.
• Output unit: Displays processed data (e.g., monitor, scanners, speakers, printer).
• Software: Series of instructions for computer tasks, categorized as system, utility, and application programs.
• Computer users: Classified as expert, casual, and basic based on their level of computer skill.
• Computing environment: Encompasses the computer, users, building, furniture, and auxiliary devices like UPS and air conditioners.

History of Computer Technology

• Early computing devices involved the abacus, Jacquard loom (1805), and Babbage's "analytical engine" (1834).
• Mechanical devices persisted until the 1960s; analog vs. digital computers sparked debate.
• Analog computers were common into the 1960s for tasks like oil reservoir modeling.
• Digital computers are now dominant, with evolution split into generations based on:
  • Technology
  • Internal organization
  • Programming languages
• First Generation (1937-1953):
  • Used vacuum tubes as electronic switches.
  • Electronic switches were faster but initially less reliable.
  • J.V. Atanasoff's machine (1937) solved equations but wasn't programmable.
  • Colossus (1943), designed by Alan Turning, broke German codes during WWII.
  • ENIAC: The first general-purpose programmable electronic computer, was built in 1945 by Eckert and Mauchly.
• Second Generation (1954-1962):
  • Used discrete diodes and transistor technology.
  • Switching times were around 0.3 microseconds.
  • TRADIC (Bell Labs, 1954) and TX-0 (MIT) are examples.
  • Magnetic core memory was used for random data access.
  • High-level programming languages such as FORTRAN, ALGOL, and COBOL were introduced.
  • IBM 704 and 7094 included I/O processors for throughput.
• Third Generation (1963-1972):
  • Used integrated circuits (ICs) with multiple transistors.
  • Semiconductor memories replaced magnetic cores.
  • Microprogramming, pipelining, parallel processing, operating systems, and time-sharing were developed.
• Fourth Generation (1972-1984):
  • Utilized Large Scale Integration (LSI - 1000 devices/chip) and Very Large Scale Integration (VLSI - 100,000 devices/chip).
  • Entire processors and computers fit on single chips with gate delays around 1 nanosecond.
  • Semiconductor memory became standard.
  • High-level languages like FP and Prolog emerged.
• Fifth Generation (1984-1990):
  • Characterized by parallel processing, with machines using hundreds of processors.
  • Semiconductor integration made chips with a million components possible, and memory became standard.
  • The use of networks and single-user workstations became widespread.
• Sixth Generation (1990-Present):
  • Defined by the rapid growth of wide area networking and increased network bandwidth.

Computer Classifications by Signal Type

• Digital: Represents variables in digits, converts data to binary form, and is used in business applications.
• Analog: Represents quantities by physical analogies like voltage or pressure. It Measures, models systems via equations, and gives exact answer
• Hybrid: Combines analog and digital elements, using digitizers for conversions. It Designed as special purpose device.

Computer Classifications by Purpose

• Special-Purpose: Designed for specific tasks, with operations built into hardware. Examples: military, navigation, process control.
  • Typically efficient, less complex, and cheaper due to limited facilities.
• General-Purpose: Handles a wide range of problems through alterable instructions; limitations in memory, speed, and I/O. Examples: payroll, banking, inventory.
  • Flexible but less efficient than special-purpose computers.

Computer Classifications by Capacity

• Capacity is measured by volume of work, cost, and memory size rather than physical size.
• Microcomputers/Personal Computers: Cheapest, utilize a microprocessor chip, IBM, Apple, Dell, etc.
• Medium/Mini/Small computers
• Large computer/Mainframes.

Microcomputer Types

• Laptop Computers: Small, battery-operated.
• Notebook Computers: Smaller than laptops, but include all components.
• Palmtop Computers: Very small, fitting in the palm.

Uses of Personal Computers (Microcomputers)

• Produce documents.
• Calculate budgets.
• Analyze functions.
• Create illustrations.
• Use emails.
• Schedule projects.
• Search information.

Advantages and Disadvantages of Personal Computers

• Advantages: versatile, fast, handle multiple data, store data, reduce fatigue, and network.
• Disadvantages: costly to maintain, fragile, require skill, risk obsolescence, cause unemployment, depend on cooling.

Minicomputers

• Have a memory capacity of 128-256 KB and are reliable and smaller than mainframes.
• Introduced in 1965 by DEC.

Mainframe Computers

• Called number crunchers.
• Have a memory capacity of 4 Kbytes with a speed of 100 MIPS.
• They are large, expensive, and used by many people.

Computer Hardware Components

System Unit

• It is the main part of the computer.
• It comprises the motherboard, CPU/processor, buses, memory, and power supply unit.
  • Not the CPU alone.

Front of the System Unit

• Lights: Show power status and disk activity.
• Turbo Button: Selects computer speed.
• Reset Button: Restarts the computer after freezing.
• Power On/Off: Turns the computer on or off.
• Floppy Disk Drives: Read floppy disks; some also have CDROM or tape drives.

Back of the System Unit

• Fan Housing: Prevents overheating.
• Power Sockets: Connects power cables.
• Joystick Port: Connects a joystick.
• Serial Ports: Connects to modem or mouse using “S101” and “S102”.
• Sound Jacks: Connects speakers or microphone.
• Keyboard Port: Connects keyboard.
• Monitor Port: Connects monitor.
• Expansion Card Slots: Add expansion cards like modem or sound cards.

Inside the System Unit

• Includes electronics to run programs and instructions.
• Battery: Maintains time and installed components.
• Disk Drive Controller Card: Controls disk drives and transfers data. and links PC components with serial and parallel ports.
• Display Adapter/Video Card: links computer memory and monitor.
• Expansion Slots: Accommodates expansion cards.
• ROM Chips: Contain start-up instructions.
• RAM Chips: Hold program and data; lost when the computer turns off.
• Empty RAM Slots: Allow for memory expansion.
• CPU Support Chips: Help the CPU manage other components.
• Memory Cache: Store the data or instructions that the CPU will look at next and speed up the computer.
• Math Coprocessor: Assists CPU with calculations.
• Speaker: Emits computer sounds.
• Power Supply Unit: Converts high-voltage to low-voltage for components.
• Hard Disk Drive: The main permanent storage unit.
• Motherboard: Made of fiberglass, connects electronic components.

Disks

Floppy Disks

• Used for storing and moving data, and is available in 5¼ and 3½ inches.
• Smaller disks store more data and resist damage with either high (DS/HD) or low (DS/DD) capacity.
• Care:
  • Handle carefully, avoid heat, and store vertically away from magnetic fields.
• Write Protection:
  • Prevents data erasure or overwriting.

Auxiliary Equipment

• Ensures smooth computer operation.

Air Conditioner

• Cools the computer and prevents damage from dust.

Voltage Stabilizer

• Prevents damage from power surges and cuts.

Line Voltage Transformer

• Adjusts voltages.

Uninterruptible Power Supply (UPS)

• Converts power and stores energy to release during outages.

Computer Software

• All non-hardware resources of computer. Is the programs that make the computer active.

Program

• Series of coded instructions to solve a problem

Computer Software Classification

• Systems Software: programs to use hardware (OS, translators).
  • Closer to the system.
  • Written in low-level languages.
  • Difficult to design.
  • Less interactive, smaller, harder to manipulate
• Application Software: for user requests (word processors).
• Utility Software: Keeps the computers running (antivirus).
  • File conversion, housekeeping

Operating Systems

• An interface between users and hardware.
• Serve to control system resource allocation.
• It Provide Interface between Hardware and programmer. Facilitation of Program and Data File Creation/Modification.
• Routine Management of Low-Level I/0 Details. Fair Access to CPU for Multiple Processes. Storage allocation and device storage. Resource sharing.

Language Translators

• Translate programming language instructions.
• Source program converted to object program.
• Three Classes:
  • Assemblers translate assembly to machine code.
  • Interpreters translate and execute line by line.
  • Compilers translate high-level to machine code and look for syntax errors

Application Software

• Designed for specific tasks like word processing or spreadsheets.
• Runs as per user request.
• Mediators between system software and end-user.

Word Processors

• Creates, edits, and prints documents.

Spreadsheets

• Used for numerical reports and figures.

Graphics Packages

• Used to create images and diagrams.

Database Packages

• Software to design/manage a database.

Statistical Packages

• Solve statistical problems, (SPSS)

Desktop Publishers

• Packages used to produce documents in standard form.

Game Packages

• Packages filled with games of all kinds

Humanware

• Refers to those who design, program, and operate computers.
• Positions are system analysts, programmers, and operators. System Analysis Programming Staff Computer Operator

System Analysts

• study and design the information processing requirements

Programmers

• Prepare a Program based on Systems Analysts design

Computer Operators

• Keep the computer operating efficiently

Key Differences Between System And Application Softwares

• System software manages system resources; application fulfils user task demands.
• System is general; application is special.
• System is low-level language; application is high-level language.
• System runs independently, while application doesn't.
• System runs until powered off, application runs from the use of the application to when the user stops it
  • System - Hardware independent of Application, while application needs system to run

Overview of Programming Languages

• Computer programming languages act like an intermediate for Computer and human communication and create computer codes for the users

  • An operations code
  • The operands.
  • There are four basic types of instructions, namely:

• (a) input-output instructions;

• (b) Arithmetic instructions;
  

• (c) Branching instructions; and

• (d) Logic instructions.

Branch Instruction types

• Namely unconditional branch instruction and conditional branch instruction.

Programming Language Types

• Machine Language is the first generation and uses binary.
• Assembly Language is Low Level language and uses mnemonics. Assembly requires a language translator called an assembler to be read.
• High Level Language a third generation one and uses familiar statements

Machine Language Programming

• Hard, tedious, and error-prone
• Computer Specific

High Level Language

• Computer independent using understandable programming
• Need strict and complex structures