Computers Basics for Beginners
Hardware
Computer systems, whether large or small, multi-user or single-user, expensive or cheap,
include most of the following pieces of hardware:
Central Processing Unit-CPU
This reads machine code instructions in a form that a computer can understand from
memory and executes it. A CPU is often likened to the "brain" of a computer.
Bus
This is the connection, or data path, between the CPU and the system memory and devices
of a computer system. All data that moves from a disk drive into memory, or from memory
to the CPU, travels across the system's bus.
Random Access Memory-RAM
This holds the machine code and data that are accessed by the CPU. RAM normally
forgets everything it holds when the power is turned off.
Read-Only Memory ROM
This holds both machine code and data. Its contents may not be changed and are
remembered even when the power is turned off.
Disks
These hold large amounts of data and code on a magnetic or optical medium, and
remember it all even when the power is turned off. Floppy disks are generally removable,
whereas hard disks are not. Hard disks can hold a lot more information than floppy disks.
CD-ROM Drive
These allow digitally published information on a compact disc to be read by the computer.
The information may be in a data stream or may constitute a file system that the
operating system can read as if it were on a hard disk drive.
Monitors
These display information and come in two flavors: monochrome and color. Monochrome
monitors are rare in newer computer systems.
Graphics Card
These allow the CPU to display information on a monitor. Many graphics cards have
on-board processors to decrease the load on the system processor.
Keyboard
This allows a user to enter alphanumeric information. There are several different
kinds of keyboards available, depending partly on the language of the user. For example,
Japanese keyboards are much larger than Western keyboards, as their alphabet is much
larger. The Western keyboards are often referred to as QWERTY keyboards, as these are
the first six letters on the upper left-hand side of the keyboard.
Mouse
This allows a user to position things easily on the screen using short movements
of the hand. Most mice have tails that connect them to the computer, but some
have radio or infrared connections that make the tail unnecessary.
Printer
These allow a user to obtain hard copies of information. Some printers print characters
only, whereas others may print graphics.
Tape
These are generally used for making backup copies of information stored on disks.
They are slower than disks but store large amounts of data in a fairly cheap way.
Modem
A modem allows you to communicate with other computers across a telephone line.
Different modems allow different rates of communication. Most modems even correct
for errors that are caused by a poor telephone connection.
Network Interface
A network interface card NIC allows your computer to communicate with other
computers across a high-speed link.
Other Peripherals
There are many other kinds of peripherals that computer systems can support,
including graphics tablets, optical scanners, array processors, sound cards,
voice recognition cards, and synthesizers to name a few.
