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Inside The PC
Understanding what hardware is inside a
computer is important when you are buying a new PC or
software program. Most software manufacturers list the
"Minimum System Requirements" necessary to run
a program on the side, bottom or back of the box. Below
are descriptions of some of the major components you
should be aware of.
The Motherboard is the main circuit board
inside your computer. It is the interface for all other
components of the computer. In other words, everything
else is connected to it. The Central Processing Unit or
CPU is plugged into this main board. This CPU is what
processes all the instructions and commands you give the
computer. When someone says "my computer is a
Pentium II 400 Megahertz" (abbreviated Mhz) they are
referring to the CPU type and speed. There are many types
and speeds of CPU's. Basically the most popular brand
names are AMD (Advanced Micro Devices) and Intel.
Pentium, Pentium II and Pentium III are types of Intel
CPU's. The K6 and Athlon are types of AMD CPU's. It's
like Scott brand Kleenex, Scott is the manufacturer and
Kleenex is the name of the product. Intel CPU's are the
standard in computer processors. Most hardware and
software manufacturers develop their products to be
compatible with the Intel CPU's. There are different
family's of CPU's. The first generation was known as the
8086, then the 80286 was developed, next came the 80386,
80486, Pentium (essentially the 80586), Pentium II (2nd
generation Pentium), Pentium III (3rd generation Pentium)
and Pentium IV (4th generation Pentium). With each
advancement in processor technology the operating speed
(measured in megahertz, Mhz or gigahertz, Ghz) increases.
The first generation 8086 processors typically operated
at 12 or 16 Mhz. Today's Pentium IV processors currently
operate at 3 Ghz or more. The higher the Mhz or Ghz
rating the faster the computer can process your commands
and run your programs.
The Memory or "RAM" (Random
Access Memory) is used by your computer to temporarily
store information that you are currently working on such
as a letter you are typing or a picture you are drawing
etc... and to store the program you are currently
running, such as a word processor or CAD (Computer Aided
Drafting) program. It is electrically powered and forgets
it's contents when the computer is powered down. To
permanently store your data, or documents you must SAVE
them. Saving writes the information currently in the RAM
to the hard drive for more permanent storage. Once the
information is saved to the hard drive it will be there
for you to recall until you decide that you no longer
need it and then it can be erased. For example you may
wish to OPEN or recall a letter you typed to reprint it.
The more RAM your system has the better. RAM is expressed
in Megabytes (abbreviated Mb). One Megabyte is one
million bytes. A byte is equivalent to a character like
the letter A or the number 4. Therefore you can store one
million characters in a megabyte. The more megabytes of
RAM your system has the faster and smoother the system
will run. Early computers had 4 or 8 Mb of RAM, typical
systems today have 128 or 256 even 512 Mb of RAM or more.
The minimum recommended amount of RAM to run Windows 98
or above and to use the Internet is 32 Mb. Windows 98 is
essentially limited to running with 512 Mb of RAM or
less, (search for "vcache" in the Microsoft
knowledge base for more information) while newer
operating systems like Windows 2000 and Windows XP can
take advantage of larger amounts of RAM.
The hard drive is also a type of memory,
but differs from RAM memory in that it retains the
information that you save to it after you turn the
computer off. It is the filing cabinet for everything you
create and save with your computer. It also contains the
operating system software and all your applications such
as your word processor or e-mail program. It is a
mechanical device with a motor that spins a platter which
resembles a CD ROM disk in appearance. It works in much
the same way as Floppy Disks do in that it reads and
writes the information to the disk through an
electromagnetic read/write head. Hard drives can store a
much greater amount of data than floppies however. A
3.5" floppy disk can hold 1.44 megabytes of
information. That is 1,440,000 bytes. Early computers had
no hard drives and used only floppy drives to run
programs and save data. This meant every time you ran a
program you had to insert the program floppy disk. When
you wanted to run another program you had to change the
floppy disk in the drive. Today's hard drives hold huge
amounts of information, typically hundreds of Megabytes
and most newer Pentium based systems have Gigabyte
capacities. A 486 might typically have a 345 Megabyte or
500 Megabyte hard drive. This means it can store 345
million or 500 million bytes of information respectively.
A Gigabyte is one billion (1,000,000,000) bytes. Typical
Pentium III and Pentium IV computers have 30 or 40
Gigabyte (abbreviated Gb) and larger hard drives. This
type of storage allows you to install your programs to
the hard drive, thus making a copy of the program on the
internal drive and eliminating the need to swap floppys
each time you run a program. They are also hundreds of
times faster than a floppy therefore allowing the
programs to run much more quickly and efficiently. The
hard drive is mounted inside your computer and is not
visible from the outside. The downside of hard drives is
that they do have a lifespan. Because they are mechanical
devices with motors and other moving parts they will
eventually break, which means that all the information
they contain will be lost and your computer will no
longer function until it is replaced. This is why it is
essential to back up any critical information you have on
floppy disks or Zip disks. Zip disks are relatively new.
They are physically different in size than a 3.5"
floppy disk and hold 100 Mb, 250 Mb and 750 Mb of data.
The Operating System is the underlying
software that makes your computer function. It is the
foundation on which all other programs are installed. It
"boots" your computer, gives you your desktop,
makes the mouse work, displays and manages all the icons
(the little pictures you click on to run programs) and
keeps track of where all your documents and programs are
stored to name a few of it's functions. The operating
system is to the computer as a cement foundation is to a
house. Both support the structure above. If this
foundation is compromised the rest of the structure
begins to fall apart. The operating system can be
compromised in a number of ways. Something as simple as
incorrectly shutting off the computer can damage it.
Other causes of operating system corruption are: a power
failure, a failing hard drive, accidental deletion of
critical system files, installing and uninstalling
software incorrectly and computer viruses. More often
than not the best way to fix a corrupt operating system
is to erase or "format" the entire hard drive
and start from the ground up by reloading the operating
system and all your programs (much like you would if your
were tearing down and rebuilding a house) . This is why
it is so important to keep the data you create organized
and to back it up regularly, because if you leave your
possessions in the house when you tear it down they will
be lost! DOS (The Disk Operating System), Windows 3.1,
Windows 95, Windows 98, Windows Me, Windows NT, Windows
2000 and Windows XP are all Microsoft operating systems.
There are other operating systems like IBM's OS2 (short
for Operating System 2), UNIX and Linux to name a few,
but these are less common than the Microsoft ones.
Without the operating system your computer would simply
be an expensive pile of circuit boards that doesn't
really do anything.
The Display Adapter or "Video
Card" is the circuit board that you connect your
monitor to. Its job is to display all the information on
your computer screen. Most Display Adapters or Video
cards have their own RAM memory installed right on the
card, but others use part of the systems RAM memory.
Typical Video Cards now can have 8, 16, 32, 64 Megabytes
or more of RAM. How much memory you need on your Video
Card depends on what you use your computer for. For
example, Video games, Image Editing applications and CAD
(Computer Aided Drafting) programs sometimes require more
advanced Display Adapters with lots of memory and 3D
graphics capabilities, where office type applications
such as word processing, spreadsheets and databases
require less sophisticated Video Cards.
CD-ROM stands for Compact Disk - Read
Only Memory. CD's can hold 74 minutes of audio or 650 Mb
of data. Because of their large storage capacity many
programs are distributed on CD's. For example, if you go
to the store and buy a game or word processing program it
will probably be on a CD-ROM disk. Typically you will
then place this disk in your computer, execute an
installation program on the CD, which in turn copies the
necessary information to run the program to your hard
drive and creates an icon for you to click on to start
the program. Generally you won't need the CD after that,
except to reinstall the program if your hard drive
crashes or you purchase a new computer. There are
exceptions to this however. For example, there are
Encyclopedias, Family Tree programs, and Clip Art
collections to name a few that come on CD's, sometimes
even multiple CD's. These types of programs will only
copy a small amount of information to your hard drive,
just enough to make the icon and run the program, but say
you look up Neil Armstrong, or Beethoven in your PC's
encyclopedia, it will then prompt you to insert the
correct CD in the computers CD-ROM drive to retrieve the
information. This saves valuable hard drive space for
installing other programs and saving your data. Recently
other types of CD drives have hit the market. There are
now CD-RW drives available. CD-RW drives allow you to
write your own data or audio to a special type of CD-R
and CD-RW discs. CD-R stands for CD-Recordable; these
types of discs can only be written to once. CD-RW stands
for CD-ReWritable; these discs can be written to, erased
and reused hundreds or even thousands of times.
The Floppy Drive was until recently the
main type of media used to get programs and data in and
out of your computer, and to move information from one
computer to another. With the introduction of ZIP drives
and Writeable CD's they are used less and less today.
Many data files are still small enough that they can be
backed up on Floppies, and some programs, although not
many are still distributed on Floppy disks. The most
common type in use today are the 3.5" Floppy Disks.
These disks can hold 1.44 Mb (that's 1,440,000 bytes) of
information. More and more computers today are shipping
without a floppy drive installed in them. If you are
considering purchasing a new PC, and you have the need
for a floppy drive, be sure to check and see if the
system you're looking at comes with one installed or not.
If you plan to connect
your computer to a Network in your home or office, or to
a high speed Broadband Internet Connection such as
Verizon DSL, Charter Communications or Comcast you need a
Network Card. Until recently Ethernet or Network Cards
were typically options in home and consumer PC's. The
dial up modem was more commonly used to connect to the
Internet from home, and having a network in your home
office was more of a luxury. Today with high speed
Broadband Internet Connections more widely available and
new homes being wired for Local Area Networks to share
these connections, the 10/100 Ethernet or Network card is
becomming standard equipmet in most new PCs.
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A modem (short for Modulate/Demodulate) is a
device that connects your computer to your phone
line and ultimately to the outside world and
networks like the Internet. They also allow you
to send and receive faxes and setup your computer
as a sophisticated answering machine or even a
fax back system that can automatically send
people predetermined documents at their request.
Modem speeds have increased from 300 bps (bits
per second) to 56,000 bps over the last several
years. The higher the bps rating the faster the
modem can transfer information from the Internet
to your computer and the smoother things appear
to run.
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Internal Data/Fax
Modem
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USB (Universal
Serial Bus) Ports are a
relatively new type of interface on today's PC's.
Designed in part to help relieve the problem of hardware
conflicts, USB ports allow the "daisy chaining"
of multiple devices such as scanners, printers, digital
cameras and other peripherals on a single connector or
"port" in the computer. An improvement over its
predecessor, the standard serial port, which can only
manage one device at a time, the USB Port can also
transfer information faster.
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