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Welcome to the PC Basics Guidebook.  This book contains information about basic PC fundamentals, terms, and concepts.  This information can also be used to succeed at "The Adventures of Dr. Tekno:  The Search for the Brigands of the South Seas."  Select a topic to learn about by clicking on the topic name or number.  To get to this Table of Contents any time, click on the PC Basics Guidebook icon.
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MICROPROCESSOR
A microprocessor or CPU (central processing unit) chip is the brain of the PC.  It is a tiny chip composed of hundreds of thousands of microscopic electrical circuits etched on a piece of silicon.  The microprocessor processes the data requests for the PC.  It can process large amounts of information very quickly. 
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There are different types of Intel microprocessors, used in PCs, from the older 8086 to the new Intel Pentium microprocessor.  The differences are represented in the chart.
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The Intel 486 CPU chip contains a built in cache, which adds to its processing speed.  Cache is a memory buffer that speeds up the operation of the PC by holding the most recently used data.  If you need the same data again it is supplied from cache (fast) instead of main system memory or disk (slower).  Cache is usually composed of very fast memory chips and can be up to ten times faster than a PC's main memory.
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MEMORY
Memory is an area within a computer that is used for temporarily storing information.  Data is stored and accessed in different quantities.  These are:
BIT-  Shortened version of Binary digit; a bit is represented by a single zero or one.
BYTE-  Refers to the eight bits that make up a character, such as a capital "A".
KILOBYTE-  Abbreviated KB; refers to one thousand bytes.
MEGABYTE-  Abbreviated as MB; refers to one million bytes.
GIGABYTE-  Abbreviated as GB; refers to one billion bytes.
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Read Only Memory (ROM) is a storage device that retains information when computer power is turned off.  In a PC, ROM is used to hold a set of instructions that help the microprocessor work with the computer components.  ROM also contains the POST (Power-On-Self-Test) that is automatically run to check computer components when the computer is turned on.  Read only memory cannot be modified. 
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Random Access Memory (RAM) is used for temporary storage within the PC, sometimes called main memory.  RAM can be written to and read from.  This type of memory does not retain data when the computer is turned off.  For example, when you use an application like a word processor to create a document, that document is held in RAM until you save it to the disk.  RAM is usually faster than ROM. 
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There are two common types of RAM.  DRAM (dynamic random access memory) requires periodic electronic recharging to retain data.  DRAM normally makes up a PC's main memory.  DRAM stores a bit as an electrical charge in a microscopic electric component called a capacitor.  If there is no charge, the capacitor represents a zero.  To make sure the charge holds, the capacitor is recharged hundreds of times a second.  This is called memory refresh.  DRAM is noted for low cost, high density, small size, moderate speed and low power consumption.
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SRAM (static random access memory) chips, unlike DRAM, do not need periodic recharging or refreshing.  SRAM is faster, larger, and more expensive than DRAM.  SRAM chips are normally used for cache memory.  When the circuit is given a zero or one to store, SRAM stores it indefinitely or until the PC is turned off.  Because it does not have to be constantly recharged, SRAM works faster.
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To make memory expansion and installation easy, multiple memory chips are packaged on a board.  SIMMs (single-in-line memory modules) are small narrow circuit boards that contain eight or nine memory chips.  SIMMs plug into special slots inside the computer to give the computer additional memory.  The normal amount of memory a PC needs to run is at least 640 KB.  This memory is called BASE or CONVENTIONAL memory.  This memory is available to the operating software and user applications for storing information. 
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Today, most PCs have at least 1 MB of memory.  Memory beyond 1 MB is called Extended Memory.  Windows and newer MS-DOS programs store information in Extended Memory.  Some older MS-DOS programs refer to memory beyond 1 MB as Expanded Memory.  These older programs access memory using a special program code called an Expanded Memory Manager (EMM).  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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MASS STORAGE
Mass Storage is used to store large amounts of data permanently.  There are different mass storage devices for different storage purposes.  There are three basic types;  (1) diskette drives, (2) fixed disk drives, and (3) tape backup drives. 
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A diskette is used for easy exchange, storage, and transport of data.  Diskette drives read and write data on the diskette with a movable head.  When data is read it is transferred to the computer's RAM.  The head magnetically writes information to the disk.  The read-write head moves across the diskette much the same way as a tone arm moves across a record player.  The data recorded on diskette can easily be changed or modified in RAM and then saved back onto the diskette.
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The sizes of diskettes commonly used are 5 1/4 inch and 3 1/2 inch.  Typical capacities are 360 KB and 1.2 MB on a 5 1/4 inch diskette, or 720 KB and 1.44 MB on a 3 1/2 inch diskette.  You can identify diskette capacity by features of the diskettes.  (1) 360 KB diskettes have a hub ring.  (2) 1.2 MB diskettes have no hub ring.  (3) 720 KB diskettes have one hole used for write protection.  (4) 1.44 MB diskettes have two holes; one for write protection and the other for identification.
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Keep diskettes away from magnetized objects including TV's, speakers, paper clip holders, radios, photocopiers, metal detection devices, and magnets.  Do not set heavy items on diskettes.  Avoid extremes of hot or cold.  Do not touch the surface of the diskettes.  Do not bend diskettes.
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For even greater storage capacity, most systems contain a fixed disk drive.  They range in size from 10 megabytes to 1 gigabyte or more.  The system's first fixed disk drive is always addressed as "C".  This is because we call the first diskette drive "A" and a second diskette drive "B".  Fixed disk drives are very fast, with access times in milliseconds.
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CD-ROM (Compact Disk Read-Only-Memory) is a type of fixed disk drive used for very large amounts of read only storage.  This means the information cannot be changed by the user.  CD-ROMs are used for applications needing large amounts of storage space for sound, complex graphics, or video files.  Examples of this would be sophisticated games and multimedia encyclopedias.  CD-ROM is convenient because of its removable media.
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Tape cartridges and drives are used for long term storage of large amounts of data (10 to 500-MB and higher).  Tapes are easily transported to other locations.  Data can be recovered from a tape if a fixed disk drive fails, loses information, or if the data is deleted.  Tapes come in various sizes.  For more information on the right tape to use, refer to your tape drive owner's manual.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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MODEMS
A modem (modulator/demodulator) takes computer information (digital) and transforms it to voice form (analog).  Analog data can be transmitted using telephone lines.  Using another modem, you can transform it back to digital data.  This is how two computers can communicate over telephone lines.  Some modems send and receive facsimile pages just like fax machines.  Modems can be internal or external devices.  Some modems can even be connected to cellular phones.  The two modems shown above are internal modems.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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DISPLAY
A monitor or panel displays information to enable the computer to communicate with the user.  A monitor can display monochrome (shades of one color) or many colors at once.  There are two basic types of displays; CRT and flat panel display.  A CRT (cathode ray tube) is a tube of glass, like that used in televisions and computer terminals.  These monitors are very reliable and popular.  Flat panel displays provide a portable display because they use less power and are less bulky.
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Monochrome displays use shades of one color to show variations in a picture.  Gray scale is a series of shades of gray from light to dark.  Graphics programs often specify the number of gray scales you can use.  Color displays support more than one color at one time.  Some can only handle 16 colors while others can handle 256 or more simultaneously.
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Monitors also support different resolutions.  Resolution refers to the number of pixels or individual dots on a screen.  They are counted across (horizontal) and down (vertical); the higher the number the greater the resolution.  An example of a screen resolution is 800x600.
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Some monitors have manual adjustments of contrast (1) and brightness (2).  Contrast is the difference between the lightest and darkest areas on the display screen.  Brightness is the level of light on the screen display.
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To keep your view clear, clean the screen by using a glass cleaner sprayed on a cloth, not the screen.  If sprayed on the screen it could drip into the monitor and short out or damage the many fragile electrical parts.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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THE MOUSE and KEYBOARD
A mouse (1) is a type of pointing device used to move the cursor around the screen.  When a mouse is moved across a flat surface, the cursor moves in the same direction on the screen.  A trackball (2) performs the same function as the mouse.  The ball moves instead of the entire mouse.  An integrated mouse, such as a Compaq EasyPoint (3), works like a trackball, but is physically part of the system.
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There are two functional parts to a mouse: 
1. The button on the mouse is used for selecting the item pointed to with your mouse cursor.  Some mice may have two or three buttons, but the left button is generally the one used.  The function of the other button depends on the application software.
2.  The ball is the part of the mouse that makes contact with the flat surface.  It rolls, giving the computer an electronic signal to move the cursor in the same direction.
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You should periodically clean your mouse to keep it operating correctly.  To clean your mouse follow these steps. 
- Turn off the computer.
- Disconnect the mouse cable from the computer.
- Turn the mouse upside down, (number 1).
- Place your thumb on the arrows located on the ball retaining ring and turn counterclockwise.
- Let the ring (number 3) and the ball (number 2) fall into your hand.
- Clean the ball with water and blow into the ball cage.
- Put the ball back into the cage and return the retaining ring.
You might want to do this if your mouse pointer becomes erratic, jerky, only moves in one direction, or even freezes up.  These directions are also in your Compaq User's Guide.  
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To click the mouse, press the left button on top of the mouse.  You can click it once or twice (double clicking) depending on the application.  To drag an item, click the mouse button once and don't release it until you have moved the item to its new location.  Then release the item by releasing the mouse button.  The Windows 3.1 Tutorial, included in the Learning Center, covers the operation of the mouse and allows you to practice these skills. 
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KEYBOARD
The keyboard is an input device for the computer.  It is used to send data and information to the computer.  The keyboard uses standard typewriter keys, several specialized keys, and a number pad to input the information or perform functions.  Not all keyboards are the same, they can vary in key layout and function.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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PRINTER
A printer takes computer data and transforms it into printed images.  There are several types of printers.  A daisy wheel printer has a circular plastic disk with the alphabet and numbers on flexible fingers around the outer edge.  A hammer device is used to strike each character to print it.  A dot matrix printer prints text and graphics in a series of dots.  Each dot is put on the paper by a pin striking the ribbon.  A laser printer offers the best resolution and produces an entire page at a time by using a process similar to photocopy machines.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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INTERFACES
Compaq systems have several types of connections.  To connect peripherals to our system we use interfaces.  An interface is the interaction between the hardware, software, and user.  Port is synonymous with interface.  Compaq uses icons or small pictures to represent the different types of interfaces.  Samples of those icons are shown above.
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Parallel interfaces are generally used to connect printers.  Parallel interfaces allow parallel transmissions, which means they send eight bits at one time.  This is much faster than a serial interface.
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A serial interface sends only one bit at a time along a single wire.  This type of interface is generally used for modems or other serial devices such as printers, plotters, scanners and digitizing tablets.
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Mouse interface refers to the connection of the mouse and the system.  The mouse is an input device.  The keyboard is also an input device that instructs the CPU what to do.  The ports for both the mouse and keyboard can be interchangeable or individual depending on the model and how much space is on the back of the system unit.
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A monitor is connected using a Video interface.  This provides both text and graphics.  The microprocessor passes all information to the monitor through the VGA interface.
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PCMCIA (Personal Computer Memory Card International Association), is a card type interface that plugs into a computer.  It is used for modems, network interface cards, memory, storage, and many others.  At one end of the card are connectors which fit into a computer interface slot.  PCMCIA connections are great for portable computers because of their small size.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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BATTERIES AND POWER
There are three common battery types: Lithium (1), Nickel Cadmium or NiCad (2), and Nickel Metal Hydride or NiMH (3).  Lithium has twice the capacity of NiCad and triple the voltage with less weight.  Lithium batteries are used for time, date, and calendar maintenance.  NiCad batteries are made of nickel and cadmium compounds.  NiCad is reliable and inexpensive.  NiMH batteries have energy capacities that are higher than NiCad and can hold a charge longer, withstand up to 1,000 charges, and tolerate a broader temperature range.
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Batteries used in portable computers can be recharged from up to 1,000 times.  Many factors influence the life of a battery.  Reduced screen brightness, screen savers, and proper conservation measures prolong battery life.  High temperatures cause batteries to lose their charge faster, so they should be stored in a cool, dry place.  Discharge your battery about every 60 - 90 days as described in your User's Guide.  Self discharge is a natural tendency for batteries to lose their charge, even when they are not being used.  The rate is about 2% a day.  The higher the temperature, the faster a battery self discharges. 
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Power conservation is used in both portable and desktop PCs.  In portables it helps the batteries last longer between charges and in the overall life of the battery.  In desktops it is used to save electricity and money. 
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Three terms are used when talking about Compaq power conservation; Standby, Hibernation, and Energy Saver.  Standby shuts down components while retaining your place in your work.  Hibernation is a feature that saves all open files to the fixed disk drive and turns the unit off.  With hibernation, when you power back up, you are back working where you were.  Energy Saver is a desktop PC feature that allows the user to set timers to control power to inactive devices. 
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Proper disposal and recycling of batteries is important.  Many battery elements are poisonous or toxic to the environment.  In North America, Compaq has a disposal/recycling program that will send you a pre-addressed, postage paid battery mailer, which is directly forwarded to the recycling facility.  Check with your local Compaq office for details on programs offered in your area.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.  
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REFERENCES
To make using your computer easy, Compaq has documentation to help you.  Compaq systems have an On-Line user's guide, dictionary,  and reference documentation installed on your PC for quick access to information.  The on-line documentation may include information about configuration, software utilities, device drivers, frequently used MS-DOS commands, and procedures on using your computer and optional equipment.  
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Some systems come with a printed user's guide.  This is a comprehensive document with the procedures you need to get started and use your computer.  This document also contains the phone numbers of your local Compaq office.  That concludes this section.  Select the PC Basics Guidebook icon to return to the menu, or the right arrow to continue with the next topic.
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