Basic Computer Concepts and Technology Notes

Basic Computer Concepts and Technology

Content Overview

• 1.1 - Concept of Computer

• 1.2 - Hardware, Software trends and Technology

• 1.3 - Disk operating system and Windows

• 1.4 - MS Word

• 1.5 - MS Excel

• 1.6 - MS Access

• 1.7 - MS Powerpoint

1.1 - Computer System

• Computer:

  • An electronic device.

  • Distinction between Electrical and Electronic devices:

    • Electrical devices convert electrical energy into other forms of energy (heat, light, sound).

    • Electronic devices control the flow of electrons to perform tasks.

  • Smart Device:

    • An electronic gadget able to connect, share, and interact with users and other smart devices.

  • Definition:

    • A machine programmable to carry out sequences of arithmetic or logical operations (computation) automatically.

    • Modern digital electronic computers perform generic sets of operations known as programs.

    • These programs enable computers to perform a wide range of tasks.

  • Computer System:

    • A nominally complete computer including hardware, operating system (main software), and peripheral equipment needed for full operation.

    • Also refers to a group of computers linked and functioning together (computer network or cluster).

• Components:

  • Hardware: Tangible/physical parts (VDU, CPU, Peripherals, etc.).

  • Software: Set of instructions, data, or programs used to operate computers and execute specific tasks. Opposite of hardware. Generic term for applications, scripts, and programs.

  • User: Person using computers for work, entertainment, communication, or business.

History of Computer

• Evolution of Computers:

  • Abacus (3000 BC)

  • Napier Bones (1617)

  • Pascaline (1642)

  • Leibniz Wheel (1685)

  • Jacquard Loom (1804)

  • Analytical Engine (1833)

  • Census Machine (1889)

  • Mark I (1944)

• Computer Generations:

  Generation	Technology	Examples	Software Examples
  First	Vacuum tubes and relay	ENIAC	Machine language (1's and 0's)
  Second	Transistors	IBM 7090	FORTRAN
  Third	MSI (medium-scale integration)	PDP-8, IBM 370	OS; pipelining; time-sharing, parallel
  Fourth	VLSI (very large scale integration)	Sun SPARC, Cray X-MP	Compiler environments
  Fifth	ULSI (ultra-large scale integration)	Cray MPP, CM2	Massively parallel processing

Computer Hardware

• Types of Computer Hardware:

  • Internal Hardware:

    • Motherboard

    • RAM

    • Hard Disk

    • SSD

    • CPU

  • External Hardware:

    • Monitor

    • Mouse

    • Keyboard

    • Printer

    • Speaker

Basic Function of Computer

• Input

• Process

• Output

• Storage

What is Hardware?

• Physical devices (aspect) of a computer

• Classified into:

  • CPU (Central Processing Unit)

  • Peripherals

Computer Peripherals

• Input/output (I/O) devices

• Usually electromechanical devices

• Online vs offline devices

Input Devices

• Allow users to input data and instructions to the computer

Examples of Input Devices

• Keyboard:

  • Invented in 1875 by Christopher Latham Sholes (father of the typewriter).

  • QWERTY keyboard (enhanced) has 101 keys.

  • Electronic typewriter keyboard.

  • Three types of keys:

    1. Alphanumeric keys

    2. Punctuation keys

    3. Special keys (alt, arrow/navigation, backspace, caps lock, ctrl, delete, enter, esc, function, insert, prt sc, home, end, page down, page up)

• Mouse:

  • Invented in 1963 by Douglas Engelbert at Stanford Research Institute.

  • Small hand-held ‘point and click’ device.

  • Three types of mouse:

    1. Mechanical Mouse

    2. Optomechanical Mouse

    3. Optical Mouse

  • Common terms used with mouse directions/actions:

    1. Point (hover over)

    2. Click

    3. Double Click

    4. Drag

    5. Select

• Light pen:

  • Consists of stylus connected by a cable to the computer

• Trackball:

  • Originally built into keyboard

  • Use hand over the trackball to move the cursor on the screen

• Joystick:

  • Small vertical stick attached to trackball for easier mechanical movements

• Scanner:

  • Convert hardcopy to softcopy

  • Direct-entry input device

• Barcode Scanner:

  • Uses optical scanner to read barcode and converts it into electrical pulses (or simply characters)

• Voice Recognition Systems:

  • Special microphone used to capture voice as an input

  • Converts voice into electrical pulses to digital signals then transmission to a computer

  • Limited vocabulary of words (voice command)

• Digital cameras:

  • Used to capture images (digitally)

Output Devices

• Display the result of the computer.

Examples of Output Devices

• Visual display unit or Monitor:

  • Television-like screens that provide the user interface in the form of displaying text, numbers and images

  • Can be monochrome or colored

• Audio response system or Speaker:

  • Can produce verbal output (sound)

• Printers:

  • Produce hardcopy output.

  • Three broad groups of printers:

    • Character printer, line printers, page printers

  • Classification of printers:

    • Impact printers or non-impact printers

Character Printer

• Dot Matrix Printers (DMP):

  • Prints one character at a time

  • Produce dotted-output because of the pins on the print head

  • Speed is measured by CpS (Character per second) 50-600cps

  • Produces a lot of noise

  • Uses ribbon as an ink

• Inkjet Printer:

  • Non-impact printer

  • Quiet when working

  • Gives better quality

  • Available in black/white and in color

• Graphic Plotter:

  • Used for large format media.

  • Graphs, maps, billboards, tarpaulin

Line Printer

• Drum printer

  • Uses powder as an ink

  • Available color: Grayscale

Page Printer

• Laser printer

  • High-end printer

  • More expensive than inkjet printers

  • Available color: Grayscale

• Magnetic Printer

  • Drum coated with magnetic material that capture the image of the page to be printed

  • Use thermal papers

Computer Memory

• Memory is essential for storing data or information in a computer system.

• Units for measuring computer memory:

  • Bit - Smallest unit of computer memory

  • Byte - 8 \, \text{bits} = 1 \, \text{byte}

  • Kilobyte - 1024 \, \text{bytes} = 1 \, \text{KB}

  • Megabyte - 1024 \, \text{KB} = 1 \, \text{MB}

  • Gigabyte - 1024 \, \text{MB} = 1 \, \text{GB}

  • Terabyte - 1024 \, \text{GB} = 1 \, \text{TB}

• Types of Computer Memory:

  • Primary Memory (Internal):

    • RAM

    • ROM

    • Cache / Register

  • Secondary Memory (External / Portable):

    • SSD (Solid State Drive)

    • HDD (Hard Disk Drive)

    • Flash Drive

    • CD / DVD

    • Magnetic Tape

• Comparison: Primary Memory vs Secondary Memory

  Parameter	Primary Memory	Secondary Memory
  Storage validity	Temporary (Volatile)	Permanent (Non-Volatile)
  Access	Directly accessed by CPU	Cannot be directly accessed by CPU
  Volatility	Loses data on power outage	Data stored even during power failure
  Storage	Costly semiconductor chips	External hardware devices (hard drives, etc.)
  Division	RAM and ROM	No such classification
  Speed	Faster	Slower
  Stored data	Data computer is currently using	Various types of data in various formats & sizes

• Volatile vs. Non-Volatile Memory:

  • Volatile memory stores data when a computer is on but erases it when switched off.

  • Non-volatile memory remains in a computer even after the system shuts off.

• Sequential Access Memory (SAM):

  • Data is read in sequence, contrasting with Random Access Memory (RAM).

  • Usually magnetic or optical storage.

• Cache Memory:

  • Temporarily stores frequently used information, data, and programs for faster CPU access.

  • Cache hit: When data is found in cache memory, enabling quick retrieval.

• Memory Hierarchy:

  • Registers, Cache, Main Memory, Disk

  • Access time increases down the hierarchy.

  • Amount of storage increases down the hierarchy.

  • Cost increases up the hierarchy.

CPU

• Components

  • Registers

  • Arithmetic & Logic Unit

  • Control Unit

• Buses

  • Data Bus

  • Address Bus

  • Control Bus

• Registers

  • Program Counter

  • Instruction Register

  • Address Register

  • Accumulator Register

• CPU Registers

  • Special Purpose Registers

  • General Purpose Registers

  • The CPU Registers are High Speed memory area inside the processor chip

  • And used by the processor during the program execution.

Motherboard

• Components:

  • DRAM

  • Northbridge with heat sink

  • Memory slots

  • Hard drive slots

  • Power connector

  • CPU heat sinks and mounting points for fans

  • CPU socket

  • Southbridge

  • ROM

  • PCI slots

  • Backup battery

  • AGP slot

  • Connectors for peripherals (e.g. audio, Ethernet, serial port, USB, etc.)

Computer Speed

Ports

• Examples:

  • VGA

  • Mini DVI

  • HDMI

  • Audio

  • Optical audio

  • DVI-I

  • DVI-D

  • Thunderbolt

  • DisplayPort

  • Mini DisplayPort

  • PS/2

  • SATA

  • eSATA

  • Ethernet

  • Modem

  • USB type A

  • USB type B

  • USB type C

  • USB micro

  • USB mini

Cloud Computing

• On-demand delivery of computing services (servers, storage, databases, networking, software, and analytics).

• Allows saving files remotely instead of on a proprietary hard drive or local storage device.

• Offers cost savings, increased productivity, speed, efficiency, performance, and security.

• Types:

  • Software-as-a-Service (SaaS):

    • Licensing software applications to customers, typically via pay-as-you-go or on-demand models (e.g., Microsoft Office 365).

  • Infrastructure-as-a-Service (IaaS):

    • Delivers everything from operating systems to servers and storage through IP-based connectivity as an on-demand service (e.g., IBM Cloud, Microsoft Azure).

  • Platform-as-a-Service (PaaS):

    • A platform for creating software delivered via the Internet (e.g., Salesforce.com, Heroku).

DOS (Disk Operating System)

• A string of characters that tells the computer what to do.

• Typing commands involves conversing with the operating system's command interpreter.

• Example: C:\> copy a:\file.txt c:\ (copies file.txt from floppy drive to hard drive).

Entering the DOS Environment

• If the OS is DOS, the system will directly show prompt (C:>).

• If the OS is Windows, either terminate the Windows environment or open a DOS shell.

  • Method 1: Terminating Windows

    • Select “Restart in MS-DOS Mode” from Shut Down in Start Menu.

  • Method 2: Opening DOS Shell in Windows

    • Select Start>Programs>Accessories>Command Prompt (XP)

    • Start>Programs>Accessories>MS-DOS Prompt (98)

Files and Directory

• Files:

  • A collection of Records.

  • Smallest unit of File System (Storage) in a computer.

  • Any document created using computer (letter, excel sheet, image, database).

• Directory:

  • A collection of files (in DOS) or folder (in Windows).

  • Analogous to the Office Folder which contains various documents.

  • Eases management of related files (e.g., personnel circulars in a “personnel” directory).

File Names in DOS

• Format: <name>.<ext>

• Two parts: name and extension.

• Name: up to 8 characters.

• Extension: up to 3 characters.

• Can contain alphabets and numbers.

• Cannot contain special characters other than underscore (_) and no spaces.

Organization of Files in DOS

• Hierarchical file system.

• Files collected into directories, which may contain files and other directories.

• Root directory: represented by the backslash '\' character.

• Path: Specifies a file by enumerating all directories between the root and the file, separated by backslashes '\'.

• Drive: Specified at the head of the path, separated from the root by a colon ':'.

• Hard drive: C: drive.

• Floppy drives: A: (3-1/2 inch) and B: (5-1/4 inch).

Some DOS Commands

• dir: Listing of all the directories.

  • C:\> dir

• cls: Clears the screen.

  • C:\> cls

• copy con: Creates a file.

  • C:\> copy con <filename>

  • < Write your Contents Here>

  • Press Ctrl-Z (^Z) to finish writing.

  • Example:

    • C:\> copy con test.dat

    • Lets Make UCO a top class Bank.

    • Ctrl-Z (^Z)

    • 1 file(s) copied (message shown on system).

• edit: Edits a file.

  • C:\> edit <filename>

  • Opens an editor window to view and edit file contents; saving changes the file.

• type: Displays the content of a file.

  • C:\> type <filename>

  • Displays file contents, but cannot be changed.

• md: Make Directory.

  • C:\> md <directory name>

  • Creates a directory with the specified name.

• cd: Change Directory.

  • C:\> cd <directory name>

  • Changes the directory from the current directory to the specified directory.

• rd: Remove Directory.

  • C:\> rd <directory name>

  • Removes the directory permanently from the computer; the directory should be empty and user should be on a directory above it.

• copy: Copies a file.

  • C:\> copy <source> <destination>

  • Copies the file from the source location to the specified destination; the file would be found on both locations.

• move: Moves a file.

  • C:\> move <source> <destination>

  • Moves the file from the source location to the specified destination; the file from the source location would be removed.

• ren: Renames a file.

  • C:\> ren <old filename> <new filename>

  • Changes the name (rename) of the file to a new name as specified.

• del: Deletes a file.

  • C:\> del <filename>

  • Deletes the file permanently from the system.