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General background information

An overview of computer programming

I recognize that some of you may not be ready for the kind of technical detail that I will provide in this section. If so, feel free to skipahead to the section titled Preview of the Scratch program . Just remember that this material is here waiting for you to come back and studyit when you are ready.

Not especially difficult

Computer programming is not especially difficult. However, it does require an aptitude for solving problems. In fact, a computer program is usually a modelfor a solution to someone's problem.

One step at a time

If you can learn to program a Digital Video Recorder (DVR), you can probably also learn to program a computer. Of course, a computer is more complicated than a DVR, so there is moreto learn. The important thing is to take the learning process in deliberate steps making certain that you understand each step before moving on to the nextone.

The hard work is often done for us

Fortunately, when we write programs using a high-level programming language such as Scratch, much of the hard work is done for us behind thescenes. For example, we don't have to perform the small incremental steps that are required to divide one number by another number.

As programmers, we are more like conductors than musicians. The various partsof the computer represent the musicians. We tell them what to play, and when to play it, and if we do our job well, we produce a solution to someone's problem.


All computers contain memory of one type or another. When we speak of human memory, we are usually speaking of the things that the human remembers.However, when we speak of computer memory, we are usually speaking of physical devices where data is stored for later retrieval. Most modern computers containmemory of a type that is often referred to as RAM (more on RAM later) .

All data is stored in a computer as numeric values. Computer programs do what they do by executing a series of operations on the numeric data.

Numeric data Even the text in this module is stored as numeric data in your computer. For example, theupper-case character "A" is commonly represented by the numeric value 65.

The operations that are performed on the numeric data generally consist of calculations and comparisons. It is the order and the pattern of those operations that distinguishes one computerprogram from another.

Random access versus sequential memory

The reason the memory in most modern computers is called random access memory (RAM) is that it can be accessed in any order. Some types of memory, such as a magnetic tape, can only be accessed in sequential order. (Yes, I did use computers with magnetic tape memory in my younger days during the sixties andseventies.)

Sequential access means that to get a piece of data that is stored deep inside the memory, it is necessary to start at the beginning and examine every piece of data until the correct one is found. Thisis typically a slow process.

Combination random/sequential memory

Other types of memory, such as disks provide a combination of sequential and random access. For example, the data on a disk is stored in tracks that formconcentric circles on the disk. The individual tracks can be accessed in random order, but the data within a track must be accessed sequentially starting at aspecific point on the track. While faster than magnetic tape, even this process is usually slower than true random access memory.

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, Teaching beginners to code. OpenStax CNX. May 27, 2013 Download for free at http://cnx.org/content/col11498/1.20
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