# 1.2 Scr0320: memory, variables, and literals in scratch 2.0  (Page 2/11)

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## 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.

## Memory

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.

what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
how did you get the value of 2000N.What calculations are needed to arrive at it
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