When you press a key on the keyboard, the
information is not magically beamed to your monitors screen. Your computer has more
going on inside than the boxy, beige exterior lets on. Weve constructed a generic
representation of how information travels through your computer. (Keep in mind some
components may be positioned differently inside your own PC.)
Almost all signals, information, and functions travel through your computers microprocessor,
which is the brain of your computer. This chip also is called the central
processing unit, because this is where most of the processing takes place. The
microprocessor depends on other components to perform many specialized functions. For
instance, it needs random-access memory (RAM) as a
temporary storage space to hold the programs and files with which it is working currently.
The microprocessor also needs a hard drive or diskettes
for permanent data storage, a keyboard for data entry, and a monitor
to display the data. Other extras, such as modems and sound
cards, let the computer exchange information over telephone lines or play
start when you press the H key on the keyboard. When you depress the key, your keyboard
uses its own microprocessor to pick up the signal and translate it into a language your
system understands. The signal is transmitted to the PC via a cable that connects to a
port on the back of the computer.
2. Inside your computer, the letter travels to
the computers microprocessor, which is a very busy chip. Before it can process the
H, it first must finish processing data that was requested earlier. Thus, the H first
travels to a RAM buffer, which is like a waiting room for information. The H
shouldnt have to wait too long; keystrokes are assigned one of the highest
processing priorities in your computer.
3. When the H reaches the microprocessor, the
microprocessor translates the keystroke into information your monitor can understand. The
microprocessor passes the signal on to the video adapter card, a circuit board that
controls your monitor. The video card then passes the information along to the monitor,
where the image is placed on the screen through a combination of blue, green, and red
dots. Each red, blue, and green dot is known as a pixel.
4. What happens when you want to save that
information (yellow line in diagram)? When you open the File menu and select the Save
option, the software gets involved. The letters on-screen go to a buffer, and the
software, which is temporarily stored in RAM, grabs the data in order to save it. The
request then travels to the microprocessor, where the data is processed and passed to the
hard drive. Inside the hard drive, a read/write head magnetically stores the information
on platters, which look like miniature records.
5. All this happens at lightning-fast speed. The
more powerful your hardware components, the faster data appears on-screen and files are