Introductory Concepts
CIS 100: Introduction to Computers
Mr. A. Craig Dixon
Spring 2006
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What is a computer?
A general definition• A person or device that calculates
Includes pre-electricity devices like the abacus and Babbage’s difference engine
A modern definition• An electronic device that takes data as
input and creates information as output
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Data vs. Information
• Data – raw facts and figures, unprocessed actions
• Information – data that is organized, meaningful and / or useful
• Metadata – data whose sole purpose is to describe or clarify other data.
Metadata helps turn data into information.
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Data vs. Information
783159246
783-15-9246
SSN: 783-15-9246
John Doe’s social security number is 783-15-9246.
An example:
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Functions of a Computer
• Accept input• Process data• Produce output• Store and retrieve data
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Components of a Computer
• Hardware – devices that can be physically manipulated by the userExamples: keyboard, mouse, monitor, printer
• Software – instructions (programs) to be executed by the computerExamples: Microsoft Windows, Microsoft Word, Norton Anti-virus
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Types of hardware
• Internals • Peripherals• Media
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Internal hardware
• Typically not manipulated by the user• Handles data processing
• Tasks are usually subdivided• Processor – does the bulk of the processing• Math co-processor – handles math operations• Video card – performs display-related calculations• Sound card – passes data to sound devices
• Most hardware, both internal and external, is connected to the motherboard, which is itself internal hardware.
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Peripheral hardware
• Connected to the system unit via wires or infrared signals
• May be manipulated by the user• Divided into two categories
• Input devices• Output devices
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Input devices
• Convert analog data from the user (keystrokes, mouse movements, voice, etc.) into a form the computer can understand
• Includes keyboard, mouse, scanner, camera, and microphone
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Output devices
• Convert data from the computer to a form that can be understood by the user.
• Includes monitor, printer, and speakers
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Hardware Summarized
Hardware
Internal External
Input OutputHardware
Motherboard, video card,
sound card, etc.
Keyboard, mouse, camera,microphone, etc.
Printer, speakers,monitor, etc.
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Types of Software
• Application software• Utilities• System software• Malware
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Application software
• Allows the user to manipulate data and create information
• Most software is application softwareExamples: Microsoft Word, Excel, Access, and PowerPoint, Adobe Photoshop, games, etc.
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Utilities
• Manipulate data based on parameters specified by the user
• Often perform maintenance tasks or file format conversions
• May be included as part of a larger application
Examples: Norton Anti-virus, WinZip, Nero, Disk Defragmenter, Ad-Aware
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System software• Consists of BIOS, operating system, and drivers
• BIOS – Basic Input / Output System; executed first on boot-up
• Operating system – Allows the computer to respond to user commandsExamples: Microsoft Windows, MacOS, Linux, OS/2, Solaris
• Drivers – Tells the computer how to utilize certain pieces of hardwareSome devices that require drivers: Mice, sound cards, video cards, printers
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Plug-and-Play Drivers
• Beginning with Windows 95, the Windows operating system shipped with a set of standard hardware drivers called plug-and-play drivers.
• Hardware manufacturers created their products to use these standard drivers rather than shipping proprietary drivers with their products.
• Windows can detect plug-and-play hardware as soon as it is connected to the computer, even on the fly.
• Since the plug-and-play drivers are already present, the user can begin using the hardware immediately.
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Malware
• Software intended to cause annoyance or damage
• Often installed covertly along with an application
Examples: Viruses, worms, Trojan horses, adware, and spyware
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Media• Hardware on which data is stored• May be inside the system unit, connect directly to
the system unit, or require a disk drive to be read• Includes floppy disks, Zip disks, CD-ROMs,
DVDs, flash memory, RAM, ROM, hard disks, and tape backups• Floppy disks, Zip disks, and tape backups are
magnetic media (data is stored on a thin layer of rust.)• Hard disks, CD-ROMs and DVDs are optical media
(read by a laser)• RAM and ROM connect directly to the motherboard
inside the system unit
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Measuring storage capacity
All forms of media have a maximum capacity, measured in bytes. Metric prefixes are used to denote large numbers of bytes.
• Kilobyte (KB) = 1024 bytes• Megabyte (MB) = ~1,000,000 bytes• Gigabyte (GB) = ~1,000,000,000 bytes• Terabyte (TB) = ~1,000,000,000,000 bytes
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Breakdown of Media
Media Capacity Speed
RAM 32MB – 2 GB Very fast Self-contained
Hard disk 40 GB – 200 GB Fast Self-contained
CDs 650 MB – 1 GB Moderate Requires drive
DVDs 4.7 GB – 17 GB Moderate Requires drive
Flash 16 MB – 2 GB Moderate Either
Zip disk 100 MB – 250 MB Slow Requires drive
Floppy 1.44 MB Slow Requires drive