A personal computer is a stand-alone computer that is equipped with a central
processing unit (CPU), one or more disk drives, random access memory (RAM), a
monitor, a keyboard, and a mouse.
It comes in an assortment of shapes and sizes.
A personal computer is a device that allows you to do a lot of work in a very
short amount of time. It allows you to communicate with businesses, friends,
family and strangers around the world. It helps you organize all of your
information from your personal address book to your checkbook.
Your personal
computer will become a teacher of new skills, games, and ideas. Your computer is
YOUR personal assistant.
There are two broad categories of PCs: stay at home and portable.
Home
computers come in two basic models, desktop and tower.
The desktop model sits
horizontally on your desk while the tower model sits vertically. The tower model
has a smaller footprint and takes up less desk space. The orientation of the
system box is the only difference in the two computers. Due to their size, they
are not frequently moved.
Portable computers such as laptops and notebooks are
much smaller and are easily transported. They are lightweight and can sit
comfortably in your lap. They run on batteries and connect to household
electricity.
Hardware is a term for the physical components that are included when you
purchase a PC. They include the system box, monitor, keyboard and mouse.
You can
purchase additional hardware items such as modems, scanners CD-ROM drives, DVD
drives, video cameras and whatever else the computer gurus invent.
By
itself, hardware is not capable of doing anything. Look at your stereo. It sits
there looking nice, without emitting sounds until the hardware pieces are given
the sounds to play.
Your computer needs something to make it work. That
something is software.
A propeller head is a term of endearment I use for those people who create, build or have a hand in the development of all the computer-based technologies that we use today. In the past, we may have called these folks nerds, geeks, Poindexters or any number of not-so-endearing terms. However, the joke is on us. They are the ones creating all of the latest and greatest technologies for us to use.
Software tells the hardware how to work, what to do, and when to do it.
Software is what gives your computer its identity. It includes the basic
operating system, utility, or application programs, all expressed in a language
your hardware understands.
There is software to tell your computer to do just
about any task. Think about when you first balanced your checkbook. Either
someone showed you how to do it or you followed the instructions on the back of
your statement.
Those instructions "programmed" you on how to do the
task at hand: balancing your checkbook. Those instructions were your
"software" and you were the "hardware" that did the work.
Software applications are programs that a computer uses so that the machine
accomplishes predetermined tasks.
Each application performs a specific kind of
work, such as, word processing, desktop publishing and accounting, personal
finance, etc.
There is an application for just about any task you can think of.
Do you want to organize your stamp collection? There's software to help you do
just that. Do you want to design your next home? Yes, software exists for that
too.
A utility program is an after-market application that does housekeeping
operations to assist you in maintaining and improving your computer's
performance.
An operating system is the master control program for the computer. It is the
stored information that your computer needs to operate.
Without an operating
system all of the hardware would just sit there and collect dust! The hardware
is like your skeleton, muscles, and organs. Without a brain you would just sit
there and collect dust, too!
Sometimes we refer to the CPU as the system box or brain. It is the computer
chip that does all of the processing for the computer.
Inside this tiny chip are
millions of transistors (electrical switches) that are connected so they can
carry out mathematical calculations. Everything a computer does is essentially a
mathematical calculation.
We measure the central processing unit's (CPU) speed in megahertz (MHz).
Megahertz is a unit of measurement commonly used to compare the speeds of
computers.
The higher the CPU's megahertz rate, the faster it processes
information and instructions.
RAM is the computer's primary working memory.
RAM is used for short-term
storage while the computer does its work. It is read/write memory.
RAM is
distinguished from ROM, which is read-only memory. The more RAM you have the more
your computer can do at one time.
RAM is volatile memory. It needs to be running
to "remember" what it is doing. In case of a system failure or power
interruption, you will lose all of your work in RAM that you have not saved on a
disk drive. Save your work frequently.
Most computers these days have between 32
and 64 megabytes of RAM.
A megabyte is a large unit of measurement of storage capacity. Here is how
storage capacity is calculated:
• Bit = smallest amount of info.
• Byte =
eight bits strung together.
• Kilobyte (KB or K) = about 1000 bytes.
•
Megabyte (MB or meg) = about a million bytes.
• Gigabyte (GB or gig) = about a
billion bytes.
Storage is where the program is kept, RAM is where it works.
The amount of
space a program needs for storage on the hard drive has nothing to do with how
much RAM is needed to run the program.
Many PC programs take up several
megabytes of storage space. Many programs also require at least 16MB to 32MB (or
more) of RAM.
To run today's popular programs, make sure your computer has
adequate RAM and storage.
Disk drives allow you to store and move data from, and to, different types of
media.
There are several types of drives: floppy drive, hard drive, CD-ROM
drive, and DVD drive.
Because the computer world is ever changing, expect to see
new drives in the future that will run our programs faster and make our tasks
much simpler. In the computer world, change is good.
The biggest difference in drives is size or capacity. Drives also differ in how fast they take to find and access information.
A floppy disk drive is an economical, removable storage medium. It uses a
magnetic disk. You can record or erase it and then remove it from the computer.
You can use the removable disk repeatedly.
Today's floppy is 3.5 inches of
square, stiff plastic with a magnetic disk inside. It is called a floppy because
the original disk, way back when, was large and floppy like a hound dog's ear.
The term "floppy" is still with us.
To read or write to a floppy disk,
insert the disk into the floppy disk drive slot on the front of your system box.
The hard disk, or hard drive, is your PC's main storage device. It's
sometimes called the C:/ drive, and pronounced "cee" drive. Data is
magnetically stored there. It stores programs and data files.
A typical hard
disk holds from 1 to 10 gigabytes of storage. Much larger hard drive capacity is
available.
CD-ROMs are compact discs, read-only, removable storage media. CD-ROMs read
the data encoded on the disc and then transfer this data to the computer.
CD-ROMs are different from hard drives and floppy disks, in that you cannot
store your own information on them.
One CD-ROM can hold as much information as
about 450 floppy diskettes.
Recently, gurus created the RW CD-ROM drive: re-writeable
CD-ROM drive. It allows you to read, erase, and use it repeatedly like a floppy
drive.
Sometimes we call the monitor a CRT (cathode ray tube) and sometimes we refer
to it as a video display unit.
The monitor attaches to the video output of the
computer and produces a visual display.
Most computers these days come with a
15-inch monitor. For an additional cost you can upgrade to a larger monitor.
Large monitors are a dream to work with and make it much easier to view your
work. However, they take up more space on your desk.
It is the standard typewriter keyboard layout, used for computer keyboards.
It is the most frequently used input device for all computers.
The keyboard
provides a set of alphabetic, numeric, punctuation, symbol, and control keys.
The mouse is a control device. It controls the pointer on your computer
screen.
It is housed in a palm-sized case. When you move it on your desk, the
corresponding arrow, commonly known as the pointer, moves on the computer
screen.
Think of it as a remote control for your computer. Move the mouse left
and right, the pointer moves left and right. Move the mouse forward and
backward, the pointer moves up and down the screen. Using the mouse to command
the computer to do most tasks can eliminate many keyboard strokes.
The flashing
bar, known as the cursor, is where the work will take place on the computer
screen. To move the cursor with the mouse, place the pointer where you want the
cursor to appear and click the mouse.
Your system has expansion slots so you can add additional hardware, known as
peripherals or add-ons.
Some slots may already be taken for a sound card or
video card.
Expansion cards give the computer additional capabilities.
Multimedia is a term used to describe any program that incorporates some combination of sound, music, written text, pictures, animation, and video. Almost all of the computers on the market today are multimedia capable.
A printer is a device designed to print your computer-generated documents
onto paper. Printers vary in their quality, speed, graphics capabilities, fonts,
and even paper usage. There are dozens of brands of printers. The three most
popular types of printers are dot matrix, ink jet (bubble jet), and laser
printers.
• Dot Matrix. A dot matrix printer uses a print head and a ribbon to print a
document. These printers are inexpensive and tend to be slow and loud. Their
print quality is fair.
• Ink Jet or Bubble Jet. An inkjet printer works by spraying tiny dots of ink
onto the paper. The print head controls the spray pattern to form the print.
Excellent print quality at a reasonable price.
• Laser. A laser printer offers great quality and fast printing. It is also
more expensive than the other two types of printers.
DPI (dots per inch) is a measure of how good a printer is. The more DPI, the better the print, and the easier it is to read.
A modem is the communications hardware that allows your computer to send and
receive information from other computers, over a telephone line.
Most new
computers come with internal modems. If you have an older computer you might
have an external modem-a small box with a phone jack connected to your computer.
You will need a modem (and a telephone line) to hook up to online services and
the Internet.
Baud rate is the number of times a modem's signal changes per second when transmitting data. It is how modem speed is measured. The bigger the number, the faster you can communicate.
Yes. Common speeds for today's modems are between 28,800 and 56,600 kilobytes
per second (expressed as 28.8K and 56.6K). The existing telephone lines can only
handle up to about 56K.
The computer gurus at the telephone companies are
working on ways to improve the capabilities of the telephone lines. Cable TV
companies are working on ways to give you access to the Internet through cable
lines. All of this is an effort to give you faster access to information.
DVD stands for digital versatile disk.
DVD drives read DVDs.
A DVD holds
about 5 gigabytes of information while a CD-ROM only holds about 600 megabytes.
A CD-ROM drive cannot read a DVD. However, DVD drives can read CD-ROMs.