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This chapter discusses what computers are, how they work and how they are programmed. This chapter also includes an introduction to problem solving and program development.

Hardware and software

A computer is a device capable of performing computations and making logical decisions at speeds millions and even billions of times faster than human beings can. For example, many of today’s personal computers can perform hundreds of millions of additions per second.

Computers process data under the control of sets of instructions called computer programs . These computer programs guide the computer through orderly sets of actions specified by people called computer programmers.

A computer is comprised of various devices (such as the keyboard, screen, “mouse”, disks, memory, CD-ROM and processing units) that are referred to as hardware . The computer programs that run on a computer are referred to as software .

Computer hardware

Almost every computer may be seen as being divided into six logical units. Figure 1 illustrates the main computer components.

Input unit

This unit obtains information from various input devices and places this information at the disposal of the other units so that the information may be processed. The information is entered into computers today through keyboards and mouse devices.

Output unit

This unit takes information that has been processed by the computer and places it on various output devices to make information available for use outside the computer. Most output from computer today is displayed on screens, printed on paper, or used to control other devices.

Memory unit

The memory unit stores information. Each computer contains memory of two main types: RAM and ROM .

RAM (random access memory) is volatile. Your program and data are stored in RAM when you are using the computer.

Basic hardware units of a computer

ROM (read only memory) contains fundamental instructions that cannot be lost or changed by the user. ROM is non-volatile.

Arithmetic and logic unit (alu)

The ALU performs all the arithmetic and logic operations. Ex: addition, subtraction, comparison, etc.

Central processing unit (cpu)

The unit supervises the overall operation of the computer. The CPU tells the input unit when information should be read into the memory unit, tell the ALU when information from the memory should be used in calculations and tells the output unit when to send information from the memory unit to certain output devices.

Secondary storage

Secondary storage devices are used to be permanent storage area for programs and data.

Virtually all secondary storage is now done on magnetic tapes, magnetic disks and CD-ROMs.

A magnetic hard disk consists of either a single rigid platter or several platters that spin together on a common spindle. A movable access arm positions the read and write mechanisms over, but not quite touching, the recordable surfaces. Such a configuration is shown in Figure 2.

The internal structure of a magnetic hard disk drive

Computer software

A computer program is a set of instructions used to operate a computer to produce a specific result.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Programming fundamentals in c++. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10788/1.1
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