Computer
A computer is an electronic device that is designed to work with information. The computer takes information in, processes that information, and then displays the results. In this way, a computer is similar to a calculator, except that even the smallest computer is much more versatile than the most powerful calculator. Computers operate at amazingly fast speeds, with a typical computer processing millions of calculations every second.
A computer is an electronic device that is designed to work with information. The computer takes information in, processes that information, and then displays the results. In this way, a computer is similar to a calculator, except that even the smallest computer is much more versatile than the most powerful calculator. Computers operate at amazingly fast speeds, with a typical computer processing millions of calculations every second.
Computer hardware consists of the physical components of your computer: the parts, devices, buttons, and ports that you can touch and physically manipulate. Computer hardware comes in two basic varieties: external and internal.
External Hardware
External hardware, also known as peripherals, refers to hardware that connects to the outside of the computer case. The monitor, keyboard, and
mouse are the most common external hardware devices. The printer and speakers are also popular peripherals. You can connect external hardware to your computer through the computer ports described on the previous page.
External hardware, also known as peripherals, refers to hardware that connects to the outside of the computer case. The monitor, keyboard, and
mouse are the most common external hardware devices. The printer and speakers are also popular peripherals. You can connect external hardware to your computer through the computer ports described on the previous page.
Internal Hardware
Internal hardware refers to hardware that resides inside the computer case. This includes the central processing unit (CPU) — the brains of the computer — memory chips that are used for temporary data storage while you work, disk drives that are used for long-term storage, and circuit boards that supply many of the ports on the back of the computer case. You can learn more about internal hardware devices i
Internal hardware refers to hardware that resides inside the computer case. This includes the central processing unit (CPU) — the brains of the computer — memory chips that are used for temporary data storage while you work, disk drives that are used for long-term storage, and circuit boards that supply many of the ports on the back of the computer case. You can learn more about internal hardware devices i
Computer software provides the instructions that enable the computer hardware to perform its tasks. Without software, your monitor would not display anything, your speakers would remain silent, and typing on the keyboard keys would have no effect. Computer software comes in two basic categories: application and system.
Application Software
Application software refers to the programs that you interact with to perform specific computer tasks. For example, a word-processing program enables you to create documents such as memos and letters, a graphics program enables you to draw an image, and an e-mail program enables you to send and receive e-mail messages.
Application software refers to the programs that you interact with to perform specific computer tasks. For example, a word-processing program enables you to create documents such as memos and letters, a graphics program enables you to draw an image, and an e-mail program enables you to send and receive e-mail messages.
System Software
System software refers to programs that operate behind the scenes to ensure that your computer system functions properly. This software is most often referred to as the operating system. Some examples of system software include Windows Vista and Mac OS X. For more information about the operating system, see Chapter 2.
System software refers to programs that operate behind the scenes to ensure that your computer system functions properly. This software is most often referred to as the operating system. Some examples of system software include Windows Vista and Mac OS X. For more information about the operating system, see Chapter 2.
Discover How Your Computer works
You do not need to become an electronic engineer to use your computer. However, it does help if you know at least a little bit about how your computer works, and what processes are going on internally
when you work with your computer. This chapter introduces you to what you need to know.
when you work with your computer. This chapter introduces you to what you need to know.
Get to Know Data
Data input is the process of sending information to the computer. This information consists of either instructions for the computer or data that you want to store on the computer. This section introduces you to the main types of computer input devices.
Input Devices
Game Controller- A game controller, also called a joystick, is a
device that you can use to control the action in a computer game. You can also use the joystick to provide instructions to the computer game, such as level and tool selection.
Document Scanner- A document scanner processes a document or photo much like a photocopier, except that a digital version of the scanned item is sent to the computer. Digital Camera You can use a digital camera to take pictures, which it then stores internally in digital
form. You can then connect the camera to a computer and move the pictures from the camera to the computer. Microphone You can use a microphone to input your voice to a computer, either to provide
instructions for the computer to follow or to record a narration.
Mouse- When you move the mouse or press a mouse button, the
action sends a signal along the mouse cable to the computer,
and the operating system reacts accordingly. Keyboard When you press a key on your keyboard, a signal that identifies that key travels through the keyboard cable to your computer. Depending on
the key that you press, the operating system either displays a character or processes an instruction. Webcam A Webcam takes a series of
pictures of a live scene and then saves the pictures on a computer. These pictures can be used on Web sites to monitor an area.
Input Devices
Game Controller- A game controller, also called a joystick, is a
device that you can use to control the action in a computer game. You can also use the joystick to provide instructions to the computer game, such as level and tool selection.
Document Scanner- A document scanner processes a document or photo much like a photocopier, except that a digital version of the scanned item is sent to the computer. Digital Camera You can use a digital camera to take pictures, which it then stores internally in digital
form. You can then connect the camera to a computer and move the pictures from the camera to the computer. Microphone You can use a microphone to input your voice to a computer, either to provide
instructions for the computer to follow or to record a narration.
Mouse- When you move the mouse or press a mouse button, the
action sends a signal along the mouse cable to the computer,
and the operating system reacts accordingly. Keyboard When you press a key on your keyboard, a signal that identifies that key travels through the keyboard cable to your computer. Depending on
the key that you press, the operating system either displays a character or processes an instruction. Webcam A Webcam takes a series of
pictures of a live scene and then saves the pictures on a computer. These pictures can be used on Web sites to monitor an area.
Data Output Devices
Data output refers to the movement of data from inside the computer to an output device, such as a monitor. This often occurs automatically because the computer has been programmed to display the results of certain operations. However, it can also occur at your request. This section introduces you to the main types of data output operations. Get Acquainted with Discovering How Your Computer Works .
Display on Monitor
Your monitor is your computer’s most important output device. What you see on the screen is a reflection of what is happening inside the computer, and your programs display elements on the screen that enable you to control how the programs work. The screen also displays what you type, as well as your mouse movements. Print to Printer- When you finish working with a document, you may want
another person to view it. The easiest way to do that is to print the document on paper using your printer, and then give the resulting document, called a hard copy, to the other person. Copy to Disk
You can make a copy of a document and store it on media such as a floppy disk, CD-ROM or DVD disc, Zip disk, or memory card. This process is useful for making backup copies of important documents or for sharing data with another person. For more information about data
storage, see the section
Play on Speakers- Your computer uses speakers for sound output. These speakers may be separate units, built into the monitor, or inside the computer case. If the system has an
important message to display, the speakers may sound an alert to get your attention. You can use your speakers to play sound files, music CDs, and other
audio data.
Operating System
The operating system is the software that controls the overall operation of your computer. The operating system controls startup, application and hardware management, and shutdown. Everything that happens on your computer is initiated, processed, and approved by the operating
system, and so it is important that you understand how this important software works. Windows Vista and Mac OS X are two popular operating systems.
system, and so it is important that you understand how this important software works. Windows Vista and Mac OS X are two popular operating systems.
Startup
When you turn on your computer, the operating system immediately assumes control and prepares the computer for use. For example, it turns on devices such as the hard drive and floppy drive, and it runs various checks to ensure that the hardware is functioning properly. The operating system then displays the interface, the screen elements that you use to interact with your computer.
When you turn on your computer, the operating system immediately assumes control and prepares the computer for use. For example, it turns on devices such as the hard drive and floppy drive, and it runs various checks to ensure that the hardware is functioning properly. The operating system then displays the interface, the screen elements that you use to interact with your computer.
Files
One of the main functions of the operating system is to manage a computer’s files. A file is an electronic collection of data and nstructions that are stored as a unit. Your computer contains files that are used internally by your programs, as well as the documents, images, spreadsheets, and other data that you create. For more information about data storage, see the section “Learn About Data Storage.”
One of the main functions of the operating system is to manage a computer’s files. A file is an electronic collection of data and nstructions that are stored as a unit. Your computer contains files that are used internally by your programs, as well as the documents, images, spreadsheets, and other data that you create. For more information about data storage, see the section “Learn About Data Storage.”
Device Drivers
The operating system uses small programs called
device drivers to communicate with your computer’s
hardware. For example, if you insert a CD or DVD, the
operating system launches a device driver to read and display the contents of the disc.
The operating system uses small programs called
device drivers to communicate with your computer’s
hardware. For example, if you insert a CD or DVD, the
operating system launches a device driver to read and display the contents of the disc.
Programs
The operating system interacts with your application software. For example, when you give the instruction to start a program, the perating system finds the appropriate files and opens them. The operating system also allocates computer resources, such as memory, to your programs.
The operating system interacts with your application software. For example, when you give the instruction to start a program, the perating system finds the appropriate files and opens them. The operating system also allocates computer resources, such as memory, to your programs.
Data Input
When you press a key on your keyboard, move your mouse, use a game controller, talk into your microphone, or start a document scan, the resulting input is first intercepted by the operating system. The
system then directs the input appropriately, for example, relaying an instruction to a program or displaying a typed character on the screen.
When you press a key on your keyboard, move your mouse, use a game controller, talk into your microphone, or start a document scan, the resulting input is first intercepted by the operating system. The
system then directs the input appropriately, for example, relaying an instruction to a program or displaying a typed character on the screen.
Data Output
When you request data output, the operating system responds to your request. For example, if you instruct a program to print a document, the operating system sends the document to the printer.
When you request data output, the operating system responds to your request. For example, if you instruct a program to print a document, the operating system sends the document to the printer.
Microprocessor
The Central Processing Unit (CPU) is the computer’s most important component because it handles, or directs, most of the tasks that occur inside the computer. The CPU is also called the microprocessor or
processor.
processor.
What Is a CPU?
A CPU is a computer chip, which is a piece of silicon that contains small electronic devices called transistors. These transistors contain components that are just .09 microns wide (an average human hair is 100 microns wide). The latest personal computer CPUs contain over 100 million transistors and can perform billions of instructions per second.
A CPU is a computer chip, which is a piece of silicon that contains small electronic devices called transistors. These transistors contain components that are just .09 microns wide (an average human hair is 100 microns wide). The latest personal computer CPUs contain over 100 million transistors and can perform billions of instructions per second.
What Is the Function of a CPU?
The purpose of the CPU is to coordinate the flow of data throughout the computer; this is why the CPU is often called the computer’s brain. The CPU also performs math and logic calculations, sends data to
and retrieves data from memory and storage devices, and processes hardware and software instructions.
The purpose of the CPU is to coordinate the flow of data throughout the computer; this is why the CPU is often called the computer’s brain. The CPU also performs math and logic calculations, sends data to
and retrieves data from memory and storage devices, and processes hardware and software instructions.
CPU Manufacturers
The biggest manufacturer of CPUs is Intel, which makes the Core 2 Duo, Pentium, and Celeron processors. The other major CPU maker is AMD, which manufactures the Sempron and Athlon chips. Macintosh computers used to come with PowerPC chips made by Motorola, but most Macs now use Intel Core 2 Duo chips.
CPU speed
The most common measure of a CPU is its speed. The speed is measured in cycles per second (hertz, or Hz) where a cycle represents a single task performed by the CPU, such as adding two numbers. CPU speeds are usually measured in gigahertz (GHz), or billions of cycles per second.
The most common measure of a CPU is its speed. The speed is measured in cycles per second (hertz, or Hz) where a cycle represents a single task performed by the CPU, such as adding two numbers. CPU speeds are usually measured in gigahertz (GHz), or billions of cycles per second.
CPU Caches
Many CPUs come with a feature called a cache, which is a storage area where the CPU keeps frequently used data. This feature saves the CPU from having to extract that data from some more distant location in the computer’s memory, thus improving computer performance. The latest CPUs have both a cache on the chip (usually called an L1 cache) and a cache between the chip and memory (usually called an L2 or L3 cache) for maximum performance.
Many CPUs come with a feature called a cache, which is a storage area where the CPU keeps frequently used data. This feature saves the CPU from having to extract that data from some more distant location in the computer’s memory, thus improving computer performance. The latest CPUs have both a cache on the chip (usually called an L1 cache) and a cache between the chip and memory (usually called an L2 or L3 cache) for maximum performance.
Front Side Bus
The average CPU spends much of its time transferring data to and from the computer’s memory. The pathways on which this data travels are collectively called the front side bus (FSB), or simply the bus. The
FSB speed determines how fast data travels between the CPU and memory. As a result, the faster the bus speed (usually measured in MHz (megahertz, or millions of cycles per second) the faster the computer performs. For more information about memory, see
the section “Understanding Memory.”
The average CPU spends much of its time transferring data to and from the computer’s memory. The pathways on which this data travels are collectively called the front side bus (FSB), or simply the bus. The
FSB speed determines how fast data travels between the CPU and memory. As a result, the faster the bus speed (usually measured in MHz (megahertz, or millions of cycles per second) the faster the computer performs. For more information about memory, see
the section “Understanding Memory.”
Memory is a temporary work
area inside your computer. When you run a program or open a
document, the operating system loads the corresponding files
from your hard drive into memory.
area inside your computer. When you run a program or open a
document, the operating system loads the corresponding files
from your hard drive into memory.
Memory is like a carpenter’s workshop: The raw materials are stored in another room (the hard drive), and the carpenter brings them into the workshop (memory) when they are needed. When the carpenter has completed the work, the finished piece is moved from the workshop back to storage.
Memory and Performance
Because memory is where the computer holds your running programs and opens documents, the more memory you have, the more programs and documents you can have open. If you want to improve the performance of your computer, you can ask your local computer shop to add more memory to your system.
Because memory is where the computer holds your running programs and opens documents, the more memory you have, the more programs and documents you can have open. If you want to improve the performance of your computer, you can ask your local computer shop to add more memory to your system.
RAM Versus ROM
The memory that a computer uses as a temporary work area is also called random access memory (RAM), because the computer can randomly add data to and remove data from this memory. However,
keep in mind that the data in RAM is erased when you turn off your computer. In contrast, read-only memory (ROM) stores data permanently, and you cannot change this data. For example, the instructions for initializing your computer’s components when you
turn the machine on are stored in ROM.
The memory that a computer uses as a temporary work area is also called random access memory (RAM), because the computer can randomly add data to and remove data from this memory. However,
keep in mind that the data in RAM is erased when you turn off your computer. In contrast, read-only memory (ROM) stores data permanently, and you cannot change this data. For example, the instructions for initializing your computer’s components when you
turn the machine on are stored in ROM.
Memory Chip
RAM and ROM use special computer chips called memory chips. Each memory chip contains a large number of transistors that are designed to store computer data.
RAM and ROM use special computer chips called memory chips. Each memory chip contains a large number of transistors that are designed to store computer data.
Memory Module
Computers do not use memory chips individually. Instead, the chips are attached to a special circuit board called a memory module. A single inline memory module, or SIMM, holds nine memory chips
on one side of the board; a dual inline memory module, or DIMM, holds nine memory chips on each side of the board for a total of 18 chips. You can improve the performance and increase the speed of
your system by adding more memory modules.
Computers do not use memory chips individually. Instead, the chips are attached to a special circuit board called a memory module. A single inline memory module, or SIMM, holds nine memory chips
on one side of the board; a dual inline memory module, or DIMM, holds nine memory chips on each side of the board for a total of 18 chips. You can improve the performance and increase the speed of
your system by adding more memory modules.
Measure Memory: Bits and Bytes
A memory chip stores data using tiny electronic devices that are either on or off. When the state of a device is on, it has a value of 1, and when the state is off, it has a value of 0. These values are called bits, which is short for binary digit. Characters, such as letters, numbers,
and other symbols, are represented by 8-bit values, which are called bytes. For example, the letter M is represented by the following byte: 01001101.
A memory chip stores data using tiny electronic devices that are either on or off. When the state of a device is on, it has a value of 1, and when the state is off, it has a value of 0. These values are called bits, which is short for binary digit. Characters, such as letters, numbers,
and other symbols, are represented by 8-bit values, which are called bytes. For example, the letter M is represented by the following byte: 01001101.
Measure Memory: Kilobytes, Megabytes, and
Gigabytes
A byte represents a single character of data. Because computers regularly deal with thousands and even millions of characters at a time, we need a system of measurement to represent these amounts. A kilobyte (KB) represents about 1,000 bytes (equivalent to about a page of text). A megabyte (MB) is about 1,000 kilobytes (equivalent to a thick book), and a gigabyte (GB) is about 1,000 megabytes (equivalent to a small library).
Gigabytes
A byte represents a single character of data. Because computers regularly deal with thousands and even millions of characters at a time, we need a system of measurement to represent these amounts. A kilobyte (KB) represents about 1,000 bytes (equivalent to about a page of text). A megabyte (MB) is about 1,000 kilobytes (equivalent to a thick book), and a gigabyte (GB) is about 1,000 megabytes (equivalent to a small library).
Your computer’s memory is only a temporary storage area for
data. When you are finished working with your data, you can
store it in a more permanent form on a hard drive or a removable drive.
data. When you are finished working with your data, you can
store it in a more permanent form on a hard drive or a removable drive.
Hard Drive
The hard drive, also called the hard disk drive (HDD) or the hard disk, is your computer’s main permanent storage area. The hard drive sits inside the computer case and stores your programs and documents. The hard drive is a magnetic disk that holds your data even when you turn off your computer. Most current hard drives can store hundreds of gigabytes of data.
The hard drive, also called the hard disk drive (HDD) or the hard disk, is your computer’s main permanent storage area. The hard drive sits inside the computer case and stores your programs and documents. The hard drive is a magnetic disk that holds your data even when you turn off your computer. Most current hard drives can store hundreds of gigabytes of data.
External Hard Drive
Most computers contain a hard drive inside the computer case. However, you may want to add an additional hard drive to increase the storage space in your system. Because it can be difficult to install an internal hard drive, you may want to invest in an external hard drive, instead. An external hard drive remains outside of the computer case and attaches to one of the computer’s ports, usually a USB port.
Most computers contain a hard drive inside the computer case. However, you may want to add an additional hard drive to increase the storage space in your system. Because it can be difficult to install an internal hard drive, you may want to invest in an external hard drive, instead. An external hard drive remains outside of the computer case and attaches to one of the computer’s ports, usually a USB port.
CD-ROM Drive
A compact disc read-only memory (CD-ROM) drive is one in which you insert a CD-ROM disc, which may contain data, software, or music. The ROM part of the drive name means that your computer can only read the disc’s contents; it cannot change the contents.
A compact disc read-only memory (CD-ROM) drive is one in which you insert a CD-ROM disc, which may contain data, software, or music. The ROM part of the drive name means that your computer can only read the disc’s contents; it cannot change the contents.
CD-R Drive
A compact disc-recordable (CD-R) drive allows you to record, or burn, data to a CD-R disc. Keep in mind that you can record data to the CD-R disc only once. After that, you cannot change the disc’s contents. CDR drives can also read data from previously recorded
CD-R discs, as well as from CD-ROM discs.
A compact disc-recordable (CD-R) drive allows you to record, or burn, data to a CD-R disc. Keep in mind that you can record data to the CD-R disc only once. After that, you cannot change the disc’s contents. CDR drives can also read data from previously recorded
CD-R discs, as well as from CD-ROM discs.
CD-RW Drive
A compact disc-rewritable (CD-RW) drive allows you to record data to a CD-RW disc. You can add data to, and erase data from, a CD-RW disc as often as you want. CD-RW drives can also read data from CD-R and CD-ROM discs.
A compact disc-rewritable (CD-RW) drive allows you to record data to a CD-RW disc. You can add data to, and erase data from, a CD-RW disc as often as you want. CD-RW drives can also read data from CD-R and CD-ROM discs.
CD Drive Speeds
CD drive performance is generally measured by how fast it is in three categories: write speed determines how fast a CD-R drive records data; rewrite speed determines how fast a CD-RW drive records data; and read speed determines how fast the drive reads a disc’s contents. Speed is measured relative to a baseline amount. For example, a read speed of 56x means that the drive reads data 56 times faster than a music CD player.
CD drive performance is generally measured by how fast it is in three categories: write speed determines how fast a CD-R drive records data; rewrite speed determines how fast a CD-RW drive records data; and read speed determines how fast the drive reads a disc’s contents. Speed is measured relative to a baseline amount. For example, a read speed of 56x means that the drive reads data 56 times faster than a music CD player.
DVD-ROM Drive
A digital versatile disc-read-only memory (DVD-ROM) drive allows you to use a DVD-ROM disc, which may contain data or software. The ROM part of the drive name means that your computer can only read the disc’s contents; you cannot change the contents. All DVD drives can also read all CD-ROM, CD-R, and CDRW discs.
A digital versatile disc-read-only memory (DVD-ROM) drive allows you to use a DVD-ROM disc, which may contain data or software. The ROM part of the drive name means that your computer can only read the disc’s contents; you cannot change the contents. All DVD drives can also read all CD-ROM, CD-R, and CDRW discs.
DVD-R, DVD+R, or DVD±R Drive
A digital versatile disc-recordable (DVD-R, DVD+R, or DVD±R) drive allows you to record, or burn, data once to a DVD-R, DVD+R, or DVD±R disc. The ± symbol means that the drive supports both the DVD-R and DVD+R formats. DVD-R, DVD+R, and DVD±R drives can read data from previously recorded DVD-R, DVD+R, or DVD±R discs, as well as from DVD-ROM discs.
A digital versatile disc-recordable (DVD-R, DVD+R, or DVD±R) drive allows you to record, or burn, data once to a DVD-R, DVD+R, or DVD±R disc. The ± symbol means that the drive supports both the DVD-R and DVD+R formats. DVD-R, DVD+R, and DVD±R drives can read data from previously recorded DVD-R, DVD+R, or DVD±R discs, as well as from DVD-ROM discs.
DVD-RW, DVD+RW, or DVD±RW Drive
A digital versatile disc-rewritable (DVD-RW, DVD+RW,
or DVD±RW) drive allows you to record data to a
DVD-RW, DVD+RW, or DVD±RW disc. You can add
data to, and erase data from, the disc as often as you
want.
A digital versatile disc-rewritable (DVD-RW, DVD+RW,
or DVD±RW) drive allows you to record data to a
DVD-RW, DVD+RW, or DVD±RW disc. You can add
data to, and erase data from, the disc as often as you
want.
DVD Drive Speeds
DVD drive performance is generally determined by how fast it is in three categories: write speed determines how fast a DVD-R, DVD+R, or DVD±R drive records data; rewrite speed determines how fast
a DVD-RW, DVD+RW, or DVD±RW drive records data; and read speed determines how fast the drive reads a disc’s contents.
DVD drive performance is generally determined by how fast it is in three categories: write speed determines how fast a DVD-R, DVD+R, or DVD±R drive records data; rewrite speed determines how fast
a DVD-RW, DVD+RW, or DVD±RW drive records data; and read speed determines how fast the drive reads a disc’s contents.
Floppy Drive
A floppy drive is a device into which you insert a floppy disk. A floppy disk is a small (3.5 inches wide) magnetic disk that you can use to read and write data. Because floppy disks can store only about 1.44MB of data, they are rarely used these days. As a result, most computers now ship without a floppy drive.
A floppy drive is a device into which you insert a floppy disk. A floppy disk is a small (3.5 inches wide) magnetic disk that you can use to read and write data. Because floppy disks can store only about 1.44MB of data, they are rarely used these days. As a result, most computers now ship without a floppy drive.
Removable Storage
Removable storage refers to disks and cards that you can insert into and remove from special devices or ports that are attached to your computer. Popular examples include Zip disks, flash drives, and memory card formats such as CompactFlash, Memory Stick, and SecureDigital. You can use these disks with devices such as digital cameras, music players, cellular phones, and handheld computers.
Removable storage refers to disks and cards that you can insert into and remove from special devices or ports that are attached to your computer. Popular examples include Zip disks, flash drives, and memory card formats such as CompactFlash, Memory Stick, and SecureDigital. You can use these disks with devices such as digital cameras, music players, cellular phones, and handheld computers.
Memory Card Reader
With so many different memory card formats available, companies are now producing multifunction memory card readers that have separate slots for each supported format. You can connect the reader to your computer’s USB port and then insert a memory card into the appropriate slot. Many computers now also come with memory card
readers built into the front of the case.
With so many different memory card formats available, companies are now producing multifunction memory card readers that have separate slots for each supported format. You can connect the reader to your computer’s USB port and then insert a memory card into the appropriate slot. Many computers now also come with memory card
readers built into the front of the case.
Choose a Monitor and Video Card
Because you look at the monitor all day long, you should get a good monitor/video card combination that is easy on your eyes and does not break your budget.
Monitor Type
There are two types of monitors available: a cathode ray tube (CRT) is the older monitor type, and tends to be large, but inexpensive; and a liquid crystal display (LCD, also called a flat panel) is the more recent
monitor type. An LCD is smaller and sharper than a CRT, and LCD prices have dropped significantly in recent years, so LCDs are now the most popular monitor type by far.
There are two types of monitors available: a cathode ray tube (CRT) is the older monitor type, and tends to be large, but inexpensive; and a liquid crystal display (LCD, also called a flat panel) is the more recent
monitor type. An LCD is smaller and sharper than a CRT, and LCD prices have dropped significantly in recent years, so LCDs are now the most popular monitor type by far.
Monitor Size
A large monitor allows you to display more elements on the screen than a small monitor. You can determine the size of a monitor by measuring diagonally from corner to corner. Keep in mind that if
you see a computer ad that says “17-inch monitor (16.0-inch viewable image size, or v.i.s.),” this means that although the monitor has a full 17 inches of glass, only 16 inches of that glass are actually used to
display the image.
A large monitor allows you to display more elements on the screen than a small monitor. You can determine the size of a monitor by measuring diagonally from corner to corner. Keep in mind that if
you see a computer ad that says “17-inch monitor (16.0-inch viewable image size, or v.i.s.),” this means that although the monitor has a full 17 inches of glass, only 16 inches of that glass are actually used to
display the image.
Dot Pitch
To create an image on-screen, monitors activate small dots; these dots are phosphors on a CRT, and liquid crystals on an LCD. The distance between each of these dots is called the dot pitch (or pixel pitch). This
is a measure of the clarity of the monitor’s image: the smaller the dot pitch, the sharper the image. Look for a monitor with a dot pitch of .26 millimeters (mm) or less.
To create an image on-screen, monitors activate small dots; these dots are phosphors on a CRT, and liquid crystals on an LCD. The distance between each of these dots is called the dot pitch (or pixel pitch). This
is a measure of the clarity of the monitor’s image: the smaller the dot pitch, the sharper the image. Look for a monitor with a dot pitch of .26 millimeters (mm) or less.
Video Card
The video card, also known as the graphics card, is an internal circuit board that generates the images that you see on your monitor. Your main concern when purchasing a graphics card is the amount of video memory that it contains. With more video memory, you can set your computer display at a higher resolution, display more colors, and open
many large graphics files at once.
The video card, also known as the graphics card, is an internal circuit board that generates the images that you see on your monitor. Your main concern when purchasing a graphics card is the amount of video memory that it contains. With more video memory, you can set your computer display at a higher resolution, display more colors, and open
many large graphics files at once.
Choose a Printer
A printer allows you to print out a document or photo from your computer. You can choose from a variety of printers with different capabilities to meet your printing requirements.
Printer Types
A laser printer uses a laser beam to apply an electrostatic charge to a rotating drum, which then picks up the toner and applies it to the paper; lasers are fast and produce crisp images, but they tend to
be expensive. An inkjet printer outputs text and images by spraying ink on the paper; an inkjet is slower and not as crisp as a laser printer, but it offers color output for far less money. A photo printer specializes in printing images from a digital camera.
A laser printer uses a laser beam to apply an electrostatic charge to a rotating drum, which then picks up the toner and applies it to the paper; lasers are fast and produce crisp images, but they tend to
be expensive. An inkjet printer outputs text and images by spraying ink on the paper; an inkjet is slower and not as crisp as a laser printer, but it offers color output for far less money. A photo printer specializes in printing images from a digital camera.
Print Quality
Print quality, or resolution, is measured in dots per inch (dpi): the higher the quality, the sharper and more detailed the printed text or image. A typical laser printer has a print quality of 600 dpi, which
means that each square inch of print has 600 dots across by 600 dots down (this is sometimes written as 600 x 600 dpi). For photo-quality inkjet output, look for a resolution of at least 2400 dpi.
Print quality, or resolution, is measured in dots per inch (dpi): the higher the quality, the sharper and more detailed the printed text or image. A typical laser printer has a print quality of 600 dpi, which
means that each square inch of print has 600 dots across by 600 dots down (this is sometimes written as 600 x 600 dpi). For photo-quality inkjet output, look for a resolution of at least 2400 dpi.
Print Speed
Print speed is measured in pages per minute (PPM). A good laser printer for home or small office use can output pages at about 20 PPM. For inkjets and photo printers, a print speed of about 15 PPM is acceptable.
Print speed is measured in pages per minute (PPM). A good laser printer for home or small office use can output pages at about 20 PPM. For inkjets and photo printers, a print speed of about 15 PPM is acceptable.
All-In-One Printers
For a slightly higher price than a standalone inkjet printer, you can get an all-in-one printer that also enables you to send and receive faxes, copy documents, and scan documents and photos. Keep in mind that the scanning and copying components have their own resolution values, with higher values giving you better-quality scans and copies.
For a slightly higher price than a standalone inkjet printer, you can get an all-in-one printer that also enables you to send and receive faxes, copy documents, and scan documents and photos. Keep in mind that the scanning and copying components have their own resolution values, with higher values giving you better-quality scans and copies.
Add Other Peripherals
To complement your basic computer setup, you can add other hardware devices that expand the capabilities of your computer system.
Modem
If you want to establish a dial-up connection to the Internet, then you need to add a modem to your computer. A modem enables your computer to connect to the Internet through a telephone line. You
also need a modem if you want to use your computer to send or receive faxes.
If you want to establish a dial-up connection to the Internet, then you need to add a modem to your computer. A modem enables your computer to connect to the Internet through a telephone line. You
also need a modem if you want to use your computer to send or receive faxes.
Audio Accessories
For you to hear the sounds generated by your computer, such as the music from audio CDs, your system needs a circuit board called a sound card. Most computers come with sound cards installed,
although you can also upgrade to better sound cards that support Dolby digital sound and other audio features. You should also purchase separate speakers and, for the best audio experience, a subwoofer.
For you to hear the sounds generated by your computer, such as the music from audio CDs, your system needs a circuit board called a sound card. Most computers come with sound cards installed,
although you can also upgrade to better sound cards that support Dolby digital sound and other audio features. You should also purchase separate speakers and, for the best audio experience, a subwoofer.
Network Card
A network card is a circuit board that enables your computer to join a network. You also need a network card if you want to surf the Internet using a highspeed connection. For more information about
networking, see Chapter 8. For more information about the Internet.
A network card is a circuit board that enables your computer to join a network. You also need a network card if you want to surf the Internet using a highspeed connection. For more information about
networking, see Chapter 8. For more information about the Internet.
Wireless Accessories
If you want to join a wireless network with your notebook, tablet PC, or handheld PC, then you must ensure that your computer has wireless networking capabilities built in. This feature is usually designated
as 802.11b or 802.11g. You also need a wireless router. For more information,
If you want to join a wireless network with your notebook, tablet PC, or handheld PC, then you must ensure that your computer has wireless networking capabilities built in. This feature is usually designated
as 802.11b or 802.11g. You also need a wireless router. For more information,
Purchase Additional Software
Your computer’s operating system comes with a number of programs.
However, many of these programs have only minimal features, and so
you may want to upgrade to specialized applications.
However, many of these programs have only minimal features, and so
you may want to upgrade to specialized applications.
Productivity Suite
A productivity suite (also called an office suite) is a collection of programs that usually includes a word processor, spreadsheet, presentation graphics program, and a database. The most popular, as well as the most expensive, is Microsoft Office. Less expensive alternatives are Microsoft Works and WordPerfect Office.
A productivity suite (also called an office suite) is a collection of programs that usually includes a word processor, spreadsheet, presentation graphics program, and a database. The most popular, as well as the most expensive, is Microsoft Office. Less expensive alternatives are Microsoft Works and WordPerfect Office.
Graphics
If you want to create your own images, then you may want to use a different graphics program than the one that ships with your operating system. For example, you can choose graphics software such as Corel Paint Shop Pro or Adobe Illustrator. If you want to work with digital photos, consider photo-editing programs such as Adobe Photoshop Elements and Ulead PhotoImpact.
If you want to create your own images, then you may want to use a different graphics program than the one that ships with your operating system. For example, you can choose graphics software such as Corel Paint Shop Pro or Adobe Illustrator. If you want to work with digital photos, consider photo-editing programs such as Adobe Photoshop Elements and Ulead PhotoImpact.
Security
Although your operating system has limited built-in Internet security, you may want to upgrade to a more advanced security program. Some popular security programs are Norton Internet Security, ZoneAlarm Pro, and McAfee Internet Security Suite.
Although your operating system has limited built-in Internet security, you may want to upgrade to a more advanced security program. Some popular security programs are Norton Internet Security, ZoneAlarm Pro, and McAfee Internet Security Suite.
Educational
The personal computer is an excellent learning tool when you combine it with educational programs such as the Encarta Reference Library and Encyclopedia Britannica.
The personal computer is an excellent learning tool when you combine it with educational programs such as the Encarta Reference Library and Encyclopedia Britannica.
Tips on Purchase Considerations
Before you purchase a computer, you must consider other factors
before making your decision.
before making your decision.
No comments:
Post a Comment