Computer Basics and Types

Introduction to Computer

• A computer is a fast operating machine that can be used for home and business to enhance productivity.
• It is a collection of electronic parts (hardware) and electronic instructions (software) that perform basic functions such as: • Performing calculations at high speed • Taking in and storing information • Storing and executing program instructions • Making decisions using logical rules • Communicating with other systems • Exploiting internal microelectronics circuitry

Classes of Computers

• Microcomputers: • Small and humble machines • Use 8-bit or 16-bit processors • Have 16Kb to 256Kb of RAM and 5 to 10 Mb of disk storage • Used for games, basic word processing, and other applications
• Minicomputers: • Smaller, less powerful machines than mainframes • Multi-user machines with 8-bit or 16-bit processors • Have smaller address space (8-24 bits) • Used for specific tasks, such as servers or workstations
• Mainframe Computers: • Large, powerful machines • Capable of handling and processing large amounts of data quickly • Measured in millions of tasks per milliseconds (MTM) • Used in large institutions such as government, banks, and corporations

Characteristics of Computers

• Ability to perform calculations at high speed
• Ability to take in and store information
• Ability to store and execute program instructions
• Ability to make decisions using logical rules
• Ability to communicate with other systems
• Ability to exploit internal microelectronics circuitry

Computer Sizes

• Desktop Computers: • Small, compact machines • Have separate screens and keyboards • Used for general-purpose computing
• Personal Digital Assistants (PDAs): • Handheld computers • Have touch screens and audio capabilities • Used for mobile phone, web browsing, and media functions
• Palmtop Computers: • Small, lightweight machines • Have smaller screens and keyboards • Used for basic computing and data entry
• Laptop and Notebook Computers: • Portable, mobile machines • Have liquid crystal displays and keyboards • Used for mobile computing and general-purpose applications### Computer Hardware

Processing Devices

• Central Processing Unit (CPU): determines computer performance, measured by clock speed (MHz or GHz)
• Examples of CPU manufacturers: Intel, Motorola, AMD
• CPU performance is determined by the circuit board (motherboard) and connections that allow components to communicate

Memory

• Random Access Memory (RAM): temporarily stores information being processed
• Chip memory vs. disk storage: RAM is like a worktable, while disk storage is like a filing cabinet
• Typical RAM requirements: 64 Mb (minimum), 128 Mb or more (recommended)
• RAM chips come in various sizes (1 Mb to 4 Gb) and speeds, and can be expanded or replaced

Storage Devices

• Disks: store information in files, measured in bytes (e.g., kilobyte, megabyte, gigabyte, terabyte, petabyte, exabyte)
• Floppy disks: less useful due to small storage capacity
• Compact Disks (CDs): store 650 Mb of information, used for software distribution and data transport
• Digital Video Devices (DVDs): store 4.5 Gb (standard), 8 Gb (dual layer), or 16 Gb (blue-ray) of information
• Hard disks: store the majority of computer information, with capacities increasing over time (e.g., 30 Gb or more)

Computer Sizes

• Supercomputer: focused on intense numerical calculations, custom-built for one task
• Mainframe: used by large organizations for critical applications, focused on data throughput and reliability
• Server: dedicated to storing and retrieving large amounts of data
• Workstation: serves one user, with special hardware enhancements
• Portable Data Entry Terminals (PDET): handheld devices for data capture
• Embedded computer systems: general-purpose CPUs part of a machine or device

Computer Types

• Desktop computer: intended for regular use at a single location

• Laptop: portable computer

• Microcomputer: once-common term for small computers### Storage Devices

• Floppy disks come in two basic sizes: 5.25 inch and 3.5 inch, with high and low density versions.

• 3.5 inch high density disks are the most common.

• A 3.5 inch high density disk can store approximately 1.44 Mb of data, equivalent to 720 pages of text.

• CD (Compact Disk) can store approximately 650 Mb of data, equivalent to a small library.

• DVD (Digital Versatile Disk) can store approximately 4.5 Gb of data, equivalent to a feature-length movie.

• Dual layer DVD can store approximately 8 Gb of data, equivalent to a long feature-length movie with extras.

Removable Storage and Disk Drives

• Disks need a drive to read and write information.
• Each drive is designed for a specific type of disk (CD, DVD, hard disk, floppy).
• The term 'disk' refers to the storage device, while the term 'drive' refers to the mechanism that runs the disk.

USB Flash Drives

• USB Flash Drives, or thumb drives, use memory cards to store information.
• They range in capacity from 512 Mb to 8 Gb.

Tape Storage

• Tape storage is cheap and has a large capacity (e.g. 50Mb upwards).
• Video tapes can store 2Gb to 8Gb of data.
• Disadvantages of tape storage include sequential access, which makes it slow to access.

Input Devices

• Input devices accept data and instructions from the user.
• Common input devices include keyboards, mice, and light pens.
• Keyboards are used to type information into the computer.
• The QWERTY keyboard layout is the most common, but others are available for different languages.
• The keyboard has 101 keys, including special command keys such as Ctrl, Alt, and Shift.

Output Devices

• Output devices return processed data to the user.
• Common output devices include monitors, printers, and modems.
• Monitors display information on the screen.
• Printers transfer information from the screen to paper.
• Modems translate digital information to analog for transmission over telephone lines or cable.

Modems

• Modems modulate and demodulate digital signals to analog signals.
• Analog modems work at speeds of up to 56,000 baud.
• Cable, wireless, or digital subscriber lines (DSL) modems can transfer information at faster speeds.

Scanners

• Scanners transfer pictures and photographs to the computer.
• They use TWAIN software to make the scanner accessible to other software applications.

Digital Cameras

• Digital cameras allow you to take digital photographs.
• Images are stored on a memory chip or disk and can be transferred to the computer.

Case

• The case houses the microchips and circuitry that run the computer.
• There are different types of cases, including desktop, mini, midi, and full tower.
• Cases have slots for adding cards, such as IDE, ASI, USB, PCI, and Firewire.

Cards

• Cards are components added to computers to increase their capability.
• Common types of cards include sound cards, colour cards, video cards, and network cards.
• Sound cards allow computers to produce sound.
• Colour cards allow computers to produce colour.
• Video cards allow computers to display video and animation.
• Network cards allow computers to connect to each other.

Connecting a Printer to a Computer

• Computers are connected to printers by cables using plugs and sockets.
• The sockets are usually called interfaces or ports.
• Serial and parallel cables are used to connect printers to computers.
• The RS232 standard is used for serial interfaces.

This quiz covers the fundamental concepts of computers, including their ability to store information and classification into mainframe, minicomputer, microcomputer, and supercomputers. It also touches on handheld computers and their capabilities.