Computer Concepts  
What's a
Computer?		 COMPUTER

A Programmable electronic device that can store, retrieve, and process data.

Types of
Computers		 TYPES OF COMPUTERS


Supercomputer

  • Ex: Cray Research: CRAY J916 ($1 million and up)
  • Requires special staff and environment
  • Fastest, largest, costliest
  • Multi-user : 10,000
  • Used for research, weather forecasting, aircraft design, simulation, special effects

 

Mainframe Computers

  • Ex: DEC: VAX ($100,000 - $20 million)
  • Requires special staff and environment
  • Fast, large capacity
  • Multi-user : thousands of users
  • Used by large organizations - banks, univ, insurance co.

 

Midsize mainframes (minis)

  • Ex: DEC: MicroVAX ($10,000 - $500,000)
  • Scaled-down mainframe computer
  • Multi-user : hundreds
  • Used by medium to small organizations for card catalogues, accounting.

 

Microcomputers

  • Ex: Sun Workstation ($2,000 - $10,000)
  • Ex: Gateway: Pentium 4 ($500 - $5,000)
  • Ex: Apple: PowerBook notebook PC ($100 - $5,000)
  • Single-user (typically) or Multi-user : 1 - 100 or more
  • Small, portable, desktop machine
  • High-end (workstation) Used by engineers and scientists for CAD, high vol. number crunching
  • Used by individuals for personal use or in business networked
Computer
developments		 Smaller size - processors (vacuum tubes -> transistors ->IC chip)

Microprocessor - miniaturized circuitry that processes the data, etched onto a sliver (chip) of silicon (found in sand).

More powerful - miniaturization allows computer to house more components, processing over shorter "distances".

Less expensive - miniaturization allows computers to be used more places and for more purposes – mass production decreases price / assembly line used for smaller components.
 
hardware HARDWARE 

Physical components of a computer.

Input
Hardware		 Input Hardware

Devices that allow data to be put into the computer.

  • Keyboard
  • Mouse, trackball, joystick
  • Digital Camera
  • Scanning device (fax, scanner)
output
hardware		 Output Hardware

Devices that translate processed data into a form that humans can understand.

  • Screen (monitor, CRT, flat-panel display) - softcopy
  • Printer, plotter (dot-matrix, laser, ink-jet) - hardcopy
  • Speakers (beeps, tones, music, speech)
Processor &
Memory		 Processing Hardware

The component that is the brains of the computer.

CPU
     Central Processing Unit
     controls and manipulates the data.

Memory Hardware

The components that store operational data & information

RAM
    Random Access Memory
    primary storage, main memory

Components that store the programs and data that are actively being used.

Characteristics:

  • Electricity represents data & info
  • Volatile - Changes when status of electricity changes
  • Random Access to data & info
  • Memory size determines the size of programs & data

 

ROM
    Read Only Memory (not volatile, not erasable)
    Component that stores hardwired instructions to
    controls basic operations
    "Boots up the computer"

Secondary
Storage		 Secondary Storage Hardware

Devices that store data & programs permanently

  • Drive - Device that reads & write data on medium.
  • Backup - Duplicate copy of data stored on secondary storage.

Examples of media:

  • magnetic floppy disk(1.44 MB)
  • magnetic hard disk(30GB -??)
  • magnetic tape
  • CD (700 MB), CD-R, CD-RW
  • ZIP (100 MB, 250 MB, 750 MB),
  • DVD (17 GB), DVD-R, DVD-RW
  • USB jump drive (20MB - ??) (thumb drive)
Memory &
Secondary storage
size		 Data - Organized into the following units
  • Bits - Binary digIT (electrical states)
  • Byte - Character - group of 8 bits that represents a letter, number, or special symbol.
  • Nibble – 4 bits
  • Word – group of bits processed simultaneously (16 to 64 bits)

Units of measure for data -

byte - 1 character
kilo - thousand kilobyte (K) - 1024 characters
mega - million megabyte (MB) - over 1 million characters
giga - billion gigabyte (GB) - over 1 billion characters
tera - trillion terabyte (TB) - 1 trillion characters
 
Communication
hardware		 Communication Hardware

Devices that allow a computer to communicate with geographically separate devices.

Modem - Modulator/Demodulator - Electronic device that allows a computer to communicate over the telephone lines.


Cable Modem - Allows your computer to connect to the cable connection

Network card – wired or wireless card to connect to a LAN.
software SOFTWARE

(Programs) The executable step by step instructions that tell the computer how to perform a process or task.
 
system
software

 

 System Software

(operating system) Software that enables the user and application software to interact with the computer. Helps manage computer resources.

  • Windows XP, NT, 98, 2000
  • Mac OSX
  • DOS
  • Linux
  • VMS
Application
Software		 Application Software

Software that can perform useful work on general-purpose tasks.

  • word processing software
  • spreadsheet software
  • presentation software
  • website development software
  • game software
  • educational software