Hardware Reference
In-Depth Information
In addition to the essential internal components in a PC, many
other devices and technologies contribute to your computer's
usability and productivity. In this chapter, we'll explore the
uses of several types of computer peripherals.
This chapter also delves into the technologies and standards used in computer networking,
both local area networks and larger ones such as the Internet.
Peripheral Devices
There are two possible defi nitions of a
peripheral device
in the context of personal
computers. One is a device that is external to the main body of the computer. Under this
defi nition, printers, monitors, mice, keyboards, and external drives are all considered
peripherals. The other defi nition is a device that isn't essential to the computer's functioning,
regardless of its internal or external status. Under this defi nition, the monitor, keyboard, and
pointing device (such as a mouse) aren't peripherals because they're essential, but a sound
card installed inside the computer is peripheral because the computer can operate without it.
The Strata exam objectives mostly use the fi rst defi nition. However, two of the items Strata
includes, speakers and microphones, rely on a sound card (or motherboard sound support)
in order to function, so in this chapter we'll consider sound cards as peripherals too.
Printers
All printers perform the same basic function: they put image onto paper. To do this, they
all must have certain subsystems that perform these tasks, more or less in this order:
1.
Receive data from the PC.
Each printer has at least one input interface. For most
printers today, this is a USB or network connection. Older printers may use a parallel
port or serial port.
2.
Store the data in RAM. The printer contains a small amount of RAM that holds the
incoming data while it's waiting for the printer's physical print mechanism to output
it. Printers that print one line at a time (like an inkjet) have less memory than printers
that compose an entire page before transferring it to paper (like a laser).
3.
Convert the data into print instructions. Each printer has a motherboard and processor
inside that accept the data and convert it to instructions to the mechanical parts that
transfer the image to paper.
