Introduction to Computer

Special ThanksS.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 processin

g 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?