1. Terms and Acronyms
To learn Information Technology (IT) is to learn the language of acronyms and terms…
WYSISYG (pronounced WHIZ-zee-wig)
“What You See Is What You Get”
GUI: Graphical User Interface
Rick Graziani

2. Computer Basics
Students and Parents, This is an old computer basics PowerPoint that I found on the web which will give you a very basic knowledge of computers and components. You may refer to this at any time except during tests on this material! Please note, this is not original but totally downloaded from the web. You will see the “Cabrillo College” banner throughout and I appreciate those who put this together and their generosity in letting it be used to teach additional students. Johnny Bley, St. Joseph Catholic Unit School
Rick Graziani

3. What is a computer?
A computer is a electromechanical device which can be programmed to change (process) information from one form to another.
Do exactly as they are told.
Digital devices: Understand only two different states (OFF and ON)
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4. Computers are everywhere
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5. Traditional Types of Computers
General purpose computers
Mainframe
Minicomputer
Microcomputer (Personal Computer)
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6. Traditional Types of Computers
Mainframe Computers
First computers, introduced in 1950s
Used by large businesses
Typically supported 100 to 500 users
Very expensive
Used for very large processing tasks
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7. Traditional Types of Computers
Minicomputers
Typically supported 10 to 100 users
Smaller and less expensive than mainframes
The real difference is relative in terms of price, power, marketing.
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8. Traditional Types of Computers
Microcomputers (Personal Computer or PC)
Small, self-contained computers with their own CPUs
Used by home and business users
Uses a microprocessor, a CPU (Central Processing Unit) on a single chip.
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9. Portable Computer
What are these types of portable computers (a type of personal computer)?
Desktop computers
Laptop computers
Personal Digital Assistants (PDAs)
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10. Networked computer
Networked computer = Computers connected to other computers or peripheral devices (printers, etc.) to share information.
What is the difference between these two networked devices?
Dumb terminal
No CPU (uses server’s)
No Operating system (uses server’s)
Input and Output only
Intelligent terminal (computer)
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11. Embedded Computers
Embedded computers – Computers found in consumer goods in order to enhance their function.
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12. Special Purpose Computers
Special purpose or dedicated computers – A device with a specific purpose such as game system or information kiosk.
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13. Hardware versus Software
Hardware = The physical components that make up a computer system.
More in a moment…
Much more on all of these items in later presentations!
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14. Hardware versus Software
Software = The programs (instructions) that tell the computer what to do.
System Software
Application Software
Stored on a storage media such as hard disk, CD-ROM, floppy disk, tape, etc.
More later…
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15. Hardware Components This is just an overview, more later…
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16. Hardware Components
Know these!
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17. The Processor
Let’s open the box!
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18. The Processor
circuit board = a board with integrated circuits (microchips)
system board or motherboard
interface boards or expansion boards
system board or motherboard = a single circuit board with the components which make up the computer’s processor for a microcomputer, including the:
CPU (Central Processing Unit)
Memory
RAM
ROM or ROM BIOS
expansion slots
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19. Rick Graziani graziani@cabrillo.edu

20. Rick Graziani graziani@cabrillo.edu

21. The Processor: The CPU
CPU (Central Processing Unit) = A complex collection of electronic circuits on one or more integrated circuits (chips) which:
1. executes the instructions in a software program
2. communicates with other parts of the computer system, especially RAM and input devices
The CPU is the computer!
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22. Input and Output Devices
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23. Input Devices Enter information into a computer Examples: Mouse
Keyboard
Trackball
Touchpad
Light pen
Joystick
Digital camera
Microphone
Bar code reader
Scanner
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24. Output Devices Send information out from a PC Examples: Speakers
Monitors
Visual Display Unit (VDU), Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), Light-Emitting Diode (LED)
Printers
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25. System Unit - Revisited
CPU (Central Processing Unit)
Memory
RAM
ROM or ROM BIOS
expansion slots
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26. RAM (Random Access Memory)
RAM (Random Access Memory) = integrated circuits (chips) used to temporarily store software (programs, instructions) and data
“primary” storage for the CPU
electronic switches, storing ON’s and OFF’s
Temporarily stores for the CPU:
Software
operating system software
application software
Data
data (documents, spreadsheets, etc.)
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27. Inserting RAM RAM is TEMPORARY memory RAM is volatile
stores ON and OFF bits (software and data) electrically
when power goes off, everything in RAM is lost
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28. RAM: Speed Why does the CPU use RAM? The CPU is very FAST!
The CPU needs the instructions (software) and data as quickly as possible
If the CPU has to wait, so does the user
Why doesn’t the CPU use permanent storage like disk drives?
Too slow
EXAMPLE: Spellchecker
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29. RAM: Capacity The amount of RAM determines:
what software and data the user can work on
how much software and data the user can work with
Most computers have at least 256 MB (Megabytes, 256 million bytes)
“out of memory” error message from the Operating System
The more complex and sophisticated the software, the more instructions that software contains, which means larger software files.
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30. ROM (Read Only Memory)
ROM (Read Only Memory) = integrated circuits (microchips) that are used to permanently store start-up (boot) instructions and other critical information
Read Only = information which:
Cannot be changed
Cannot be removed
Cannot be appended (added to)
Fixed by manufacturer
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31. ROM (Read Only Memory)
ROM is sometimes known as ROM BIOS (Basic Input Output System software)
ROM permanently contains:
start-up (boot) instructions
instructions to do “low level” processing of input and output devices, such as the communications with the keyboard and the monitor
Firmware = software program which is stored permanently on a microchip, such as the software on the ROM chip
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32. Looking at your computer
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33. Storage Devices Storage Devices: Floppy disks CD-ROMs Hard disks
Zip disks
Tape drives
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34. Floppy disks Store up to 1.44 MB of data Usually 3.5" square disks
Removable
Write-Protect tab (Open means “write enabled”)
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35. Hard disks Fixed permanently in a hard disk drive inside a system unit
Used to store the operating system, applications, and data
Can not buy more expansion (easily)
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36. CD-ROMs
Read-only memory devices (but CD-R and CD-RW discs are recordable)
Store up to 650 MB of data
Portable and can be used on any computer that has a CD-ROM drive
CD-R (CD Recordable)
CD-RW (CD Rewritable)
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37. Flash sticks or memory Storage Digital Player Voice Recorder
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38. Zip disks Store up to 250 MB of data
Used for backing up files or transporting large files
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39. Tape drives Work like a tape recorder
Vary in capacity and access speed
Relatively expensive
Generally used to back up data
Good for “archiving” information
Types
Cartridge (slowest)
DAT (Digital Audio Tape)
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40. Computer Performance CPU speed (and type) Amount of RAM (and speed)
Hard disk capacity
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41. Computer Performance CPU Speed Governed by a clock
Measured in millions of cycles per second, or megahertz (MHz)
700 MHz means 700 million operations per second
Measured in billions of cycles per second, or megahertz (GHz)
1.133 MHz means 1 billion, 133 million operations per second
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42. Software System Software Application Software
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43. Application Software Performs specific tasks: Word processing
Calculations
Information storage and retrieval
Accounting
Cannot function without the OS (Operating System)
Written for a specific operating system and computer hardware.
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44. Operating System Software
Loads automatically when you switch on a computer
Main roles:
Controls hardware and software
Permits you to manage files
Acts as intermediary between user and applications
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45. Operating System Software
Software which manages the overall operation of the computer system including:
hardware (CPU, RAM, I/O)
security
system interface
application interface
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46. GUI – Graphical User Interface
Windows 3.1
Windows 95/98/XP
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47. GUI – Graphical User Interface
MAC OS
UNIX/LINUX with X-Windows
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48. CLI – Command Line Interface
No GUI
MS DOS
? Windows 97 ?
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49. Putting it altogether! Booting up the computer
Creating and saving a word processing document
Shutting down the computer
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50. CPU RAM 256 MB ROM Hard Disk Drive Operating System Software
“The kernel”
Application Software
MS Word
User data (information)
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