Introduction to
Computer
Special Thanks
S.W.A.Shah
NIST
You will learn about:
• Hardware including:
• Input devices.
• Processor or central processing unit
(CPU).
• Output devices.
• Memory.
• Software
• Definitions of basic computer terms
Computer Hardware:
• A computer consists of both hardware
(physical parts of the computer) and
software working together to help you
accomplish tasks.
• Hardware consists of:
• Input devices
• Processor or central processing unit
(CPU)
• Memory
Input devices:
• Input devices are machines that
communicate with the computer.
• Examples of input devices are the
keyboard and the mouse.
• Input devices are controlled by the
user.
• For example, typing on the keyboard or
clicking on a mouse button.
Processor or CPU:
• Processor or CPU:
• CPU is short for
Central Processing
Unit.
• The CPU is a microchip
inside the computer.
• The box that the
processor resides in is
commonly referred to
as the CPU.
Processor or CPU:
• The translation or processing of your input
takes place in the CPU.
• Processing is the thinking that the
computer does - the calculations,
comparisons, and decisions.
• The box contains the microchip, the floppy
disk drive, the CD-ROM drive, and
memory.
Output devices:
Output devices are machines that display information
from the computer (CPU).
• Output devices are controlled by the
computer. After the processor
translates the information from the
input devices, the output devices deliver
the information to the user.
Memory:
• The cycle (input - processing - output)
would not be possible without a holding
place for the instructions and data that
the processor (CPU) can easily reach.
• This holding place is known as memory.
• There are three basic types of memory:
types of memory
•
•
•
RAM - Random Access Memory
ROM - Read Only Memory
Storage Devices
RAM:
• The primary memory that holds data and
instructions while the computer is in use.
• Can be thought of as the memory the computer
uses to obey instructions.
• Can be written to and read from.
• Important to remember that if you do not save
the information in RAM to a storage device (such
as a floppy disk or hard drive) before turning off
the computer the information will be lost
ROM:
• ROM is more straight forward.
• ROM is built in memory that
permanently stores instructions and
data.
• The instructions and data in ROM are
created when it is manufactured and
it cannot be changed.
ROM (BIOS CHIP)
Storage Devices:
• A storage device is a place to store
data. Although there are several
types of disks, for the purposes of
this tutorial, only the following types
will be discussed:
Hard Drive:
• A permanent data storage device built into
PCs that permits you to save and retrieve
information.
• Also, stores the computer's operating
system and other software.
• The size of a hard drive is usually
expressed in terms of megabytes and
gigabytes.
Floppy Disk:
Floppy disks allow information to be transported easily
from one computer to another.
Floppy disks have limited storage capacity,
generally 1.44 MB.
Saving and retrieving information from a floppy
disk is slower than on a hard drive.
They are more susceptible to physical
damage and viruses than the hard drive.
CD ROM:
• CD ROMs are read only storage
medium.
• Typically, a CD ROM holds up to 650
MB of information.
• While information retrieval is faster
than from a floppy disk, it is still not
as fast as from the hard drive.
CD-RW:
• A CD-RW allows you to read, write, erase
and write again.
• Writing takes place in a single pass of the
focused laser beam.
• This is sometimes referred to as direct
overwriting and can be repeated several
thousand times per disc.
Computer Software:
• Software is:
• What makes the computer work.
• Software consists of an organized list of
instructions that causes the computer to
behave in a predetermined manner.
• For work, for play, for kids, and for adults.
• A computer game you play or a word
processing program.
• Often divided into two categories:
system software and application
software.
• System software includes the operating
system, compilers and utilities that
enable the computer to function.
• Application software includes programs
that perform specific tasks (e.g., games,
word processors, spreadsheets, and
databases).
• Figuratively speaking, application software
sits on top of system software because
the computer is unable to run without the
operating system and system utilities.
End of the Lecture
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