# 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.

how can chip be made from sand
is this allso about nanoscale material
Almas
are nano particles real
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
no can't
Lohitha
where is the latest information on a no technology how can I find it
William
currently
William
where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
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
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
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
how did you get the value of 2000N.What calculations are needed to arrive at it
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