What is Hardware?
Your PC (Personal
Computer) is a system, consisting of many components. Some of those components,
like Windows XP, and all your other programs, are software. The stuff you can
actually see and touch, and would likely break if you threw it out a
fifth-story window, is hardware.
Not everybody has exactly the same hardware.
But those of you who have a desktop system, like the example shown in Figure 1,
probably have most of the components shown in that same figure. Those of you
with notebook computers probably have most of the same components. Only in your
case the components are all integrated into a single book-sized portable unit.
Figure 1
The system unit is
the actual computer; everything else is called a peripheral device. Your computer's
system unit probably has at least one floppy disk drive, and one CD or DVD
drive, into which you can insert floppy disks and CDs. There's another disk
drive, called the hard disk inside the system unit, as shown in Figure 2. You
can't remove that disk, or even see it. But it's there. And everything that's
currently "in your computer" is actually stored on that hard disk.
(We know this because there is no place else inside the computer where you can
store information!).
Figure 2
The floppy drive and
CD drive are often referred to as drives with removable media or removable
drives for short, because you can remove whatever disk is currently in the
drive, and replace it with another. Your computer's hard disk can store as much
information as tens of thousands of floppy disks, so don't worry about running
out of space on your hard disk any time soon. As a rule, you want to store
everything you create or download on your hard disk. Use the floppy disks and
CDs to send copies of files through the mail, or to make backup copies of
important items.
Random Access Memory
(RAM)
There's too much
"stuff" on your computer's hard disk to use it all at the same time.
During the average session sitting at the computer, you'll probably use only a
small amount of all that's available. The stuff you're working with at any
given moment is stored in random access memory (often abbreviated RAM, and
often called simply "memory"). The advantage using RAM to store
whatever you're working on at the moment is that RAM is very fast. Much faster
than any disk. For you, "fast" translates to less time waiting and
more time being productive.
So if RAM is so fast, why not put everything
in it? Why have a hard disk at all? The answer to that lies in the fact that
RAM is volatile. As soon as the computer is shut off, whether intentionally or
by an accidental power outage, every thing in RAM disappears, just as quickly
as a light bulb goes out when the plug is pulled. So you don't want to rely on
RAM to hold everything. A disk, on the other hand, holds its information
whether the power is on or off.
The Hard Disk
All of the
information that's "in your computer", so to speak, is stored on your
computer's hard disk. You never see that actual hard disk because it's sealed
inside a special housing and needs to stay that way. Unlike RAM, which is
volatile, the hard disk can hold information forever -- with or without
electricity. Most modern hard disks have tens of billions of bytes of storage space on them. Which, in
English, means that you can create, save, and download files for months or
years without using up all the storage space it provides.
In the unlikely event
that you do manage to fill up your hard disk, Windows will start showing a
little message on the screen that reads "You are running low on disk
space" well in advance of any problems.
In fact, if that message appears, it won't until you're down to about
800 MB of free space. And 800 MB of empty space is equal to about 600 blank
floppy disks. That's still plenty of room!
The Mouse
Obviously you know
how to use your mouse, since you must have used it to get here. But let's take
a look at the facts and buzzwords anyway. Your mouse probably has at least two
buttons on it. The button on the left is called the primary mouse button, the
button on the right is called the
secondary mouse button or just the right mouse button. I'll just refer
to them as the left and right mouse buttons. Many mice have a small wheel
between the two mouse buttons, as illustrated in Figure 3.
Figure 3
The idea is to rest
your hand comfortably on the mouse, with your index finger touching (but not
pressing on) the left mouse button. Then, as you move the mouse, the mouse
pointer (the little arrow on the screen) moves in the same direction. When
moving the mouse, try to keep the buttons aimed toward the monitor -- don't
"twist" the mouse as that just makes it all the harder to control the
position of the mouse pointer.
If you find yourself
reaching too far to get the mouse pointer where you want it to be on the
screen, just pick up the mouse, move it to where it's comfortable to hold it,
and place it back down on the mousepad or desk. The buzzwords that describe how
you use the mouse are as follows:
Point: To point to an
item means to move the mouse pointer so that it's touching the item.
Click: Point to the
item, then tap (press and release) the left mouse button.
Double-click: Point
to the item, and tap the left mouse button twice in rapid succession -
click-click as fast as you can.
Right-click: Point to
the item, then tap the mouse button on the right.
Drag: Point to an
item, then hold down the left mouse button as you move the mouse. To drop the
item, release the left mouse button.
Right-drag: Point to
an item, then hold down the right mouse button as you move the mouse. To drop
the item, release the right mouse button.
The Keyboard
Like the mouse, the
keyboard is a means of interacting with your computer. You really only need to
use the keyboard when you're typing text. Most of the keys on the keyboard are
laid out like the keys on a typewriter. But there are some special keys like
Esc (Escape), Ctrl (Control), and Alt (Alternate). There are also some keys
across the top of the keyboard labeled F1, F2, F3, and so forth. Those are
called the function keys, and the exact role they play depends on which program
you happen to be using at the moment.
Most keyboards also
have a numeric keypad with the keys laid out like the keys on a typical adding
machine. If you're accustomed to using an adding machine, you might want to use
the numeric keypad, rather than the numbers across the top of the keyboard, to
type numbers. It doesn't really matter which keys you use. The numeric keypad
is just there as a convenience to people who are accustomed to adding machines.
Figure 4
Most keyboards also
contain a set of navigation keys. You can use the navigation keys to move
around around through text on the screen. The navigation keys won't move the
mouse pointer. Only the mouse moves the mouse pointer.
On smaller keyboards
where space is limited, such as on a notebook computer, the navigation keys and
numeric keypad might be one in the same. There will be a Num Lock key on the
keypad. When the Num Lock key is "on", the numeric keypad keys type
numbers. When the Num Lock key is "off", the navigation keys come
into play. The Num Lock key acts as a toggle. Which is to say, when you tap it,
it switches to the opposite state. For example, if Num Lock is on, tapping that
key turns it off. If Num Lock is off, tapping that key turns Num Lock on.
Combination
Keystrokes (Shortcut keys)
Those mysterious Ctrl
and Alt keys are often used in combination with other keys to perform some
task. We often refer to these combination keystrokes as shortcut keys, because
they provide an alternative to using the mouse to select menu options in
programs. Shortcut keys are always expressed as:
key1+key2
where the idea is to
hold down key1, tap key2, then release key1. For example, to press Ctrl+Esc
hold down the Ctrl key (usually with your pinkie), tap the Esc key, then
release the Ctrl key. To press Alt+F you hold down the Alt key, tap the letter
F, then release the Alt key.
