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computer fundamentals


Introduction to computers :

What is a Computer

A computer is an electronic device that manipulates information, or "data." It has the ability to store,
retrieve, and process data. You

can use a computer to type documents, send email, and browse the
internet. You can also use it to handle spreadsheets, accounting, database management, presentations,
games, and more.

Watch the video to learn about different types of computers.

son between computer and human brain

Brains are analogue; computers are digital

No hardware/software distinction can be made with respect to the brain or mind

term memory is not like RAM

Processing speed is not fixed in the brain; there is no system

The brain is a massively parallel machine; computers are modular and serial

The brain uses content
addressable memory

Synapses are far more complex than electrical logic gates

Unlike computers, processing and memory are performed by the same componen
ts in the brain

The brain is a self
organizing system

The brain is much, much bigger than any [current] computer.

Characteristics of Computer, Computer applications

A computer is a general purpose device that can be programmed to carry out a finite set o
f arithmetic or
logical operations.

A computer application, or application software, is computer software written using a programming
instructions. The instructions of a computer application are executed on a computer to achieve the results
described in t
he application.

History of Computers

History of Computers

Initial development

Professional development

may be separated into two distinct phases,
Continuing Professional Development

and Initial Professional Development.


Initial Professional Development (IPD) is defined by the UK Initial Professional Development Forum

as "a
period of development during which an individual acquires a level of

necessary in order to
operate as an autono
mous professional".
Professional bodies

may recognise the successful completion of
IPD by the award of chartered or similar status.

Generation of Computer

The history of computer development i
s often referred to in terms of five distinct
eras, or "generations" of computing devices. Each generation of computer is characterized by a major
technological development that fundamentally changed the way computers operate, resulting in
increasingly sma
ller, cheaper, more powerful and more efficient and reliable devices.

The First Generation: 1946 to 1955

The Second Generation: 1956 to 1963

The Third Generation:

1964 to 1970

The Fourth Generation: 1971
to 1991

The Fifth Generation: 1992 to present

Evolution of Personal Computers


The Evolution of the Personal Computer

In 1981, IBM introduced a personal computer (PC) powered by an Intel® 8088
processor. At first, the PC was not much more than a glorified typewriter or calculator,
but relentless te
chnological advances and innovation over the past quarter century
have put powerful PCs at the center of daily activities for people worldwide. Like the
telephone, automobile, and television before it, the PC has changed the way people
communicate, shop, r
etrieve information, and entertain themselves.

Computer Organisation

Computer organization" redirects here. For organizations that make computers, see
List of computer
system manufacturers
. For one classification of computer architectures, see
Flynn's taxonomy
. For another
classification of instruction set architectures, see
Instruction set#Number of operands

Intel Core


computer engineering
microarchitecture (sometimes abbreviated to µarch
or uarch), also called computer organization, is the way a given
instruction set architecture

(ISA) is
implemented on a processor. A given ISA ma
y be implemented with different microarchitectures.

Implementations might vary due to different goals of a given design or due to shifts in technology.

Computer architecture

is the combina
tion of microarchitecture and instruction set

Basic units of computer,

The control Unit

ALU:Arithmetic and Logic Unit

ut Unit or device

Memory Unit

The CPU (includes ALU and AGU)

Input devices

Output devices

Storage devices


This qu
estion is really open to interpretation. If I was looking for a general purpose description, I might say:

Computer, Keyboa
rd, Mouse, Monitor and Printer

Or I might view it from another perspective:

Computer, Keyboard, Mouse, Monitor and Operating System

Block diagram of Computer

A diagram in which the essential units of any system are drawn in the form of rectangles or blocks and their
relation to each other is indicated by appropriate connecting lines.

Block Diagram of a Computer


Input Unit, Processing Unit

Input Unit of the computer system consists of the input devices. following are the devices included in the
input unit. i.e Keyboard, Mouse, Scan
ner, Microphone

Output Unit, Storage Unit.

In computers, a unit which delivers information from the computer to an external device or from internal
storage to external storage

You can storage anything non
lethal, non
toxic, and non
flammable in a stora
ge unit, depending on the
specific rules of that unit. Some, for example, do not allow guns.

Types of Printers

Hard Copy output

A printed copy, especially of the output of a computer or word processor.

Impact Printers

A line printer that has one or m
ore character fonts, a ribbon or other inking device, a paper transport, and
some means of impacting desired characters or character elements on the paper.

Impact Printers

A printer that prints without banging a ribbon onto paper. Laser, LED, inkjet
, solid ink, thermal wax transfer
and dye sublimation printers are examples of non
impact printers. See

Serial and Line Printers

The difference between the two is simple: Line printers

use vibration and serial printers use the horizonta
movement of a printer head.

Both use a ink ribbon and are categories of the Dot
Matrix printer family. This as well as electromagnetism,
combined with small pins, to strike the ribbon and cause ink to
stick onto the pag
e in tiny dots (hence the

Matrix Printers

Dot matrix printing or impact matrix printing is a type of
computer printing

which uses a print head that
s back and forth, or in an up and down motion, on the page and prints by impact, striking an ink
cloth ribbon against the paper, much like the print mechanism on a
. However, unlike a

typewriter or
daisy wheel printer
, letters are drawn out of a
dot matrix
, and thus, varied fonts and arbitrary
graphics can be produce

Laser Printers

A printer that uses a laser to produce an image on a rotating drum before electrostatically transferring the
image to paper.

Daisy wheel printers

A printing device used in some electric typewriters and printers, consisting of printing c
haracters fixed at
the ends of spokes on a wheel.

Drum and Chain Printers

Thermal Printers.


A nonimpact printer in which characters are formed by heating selected elements of a 5 × 7 or 7 × 9 dot
matrix that is in contact with heat
sensitive paper.

ternal storage devices

An external storage device serves as extra memory for your computer which connects usually by a USB port.
Most personal external storage devices range from 100GB of storage to 1 terabyte which is 1000GB of
memory. Their prices usuall
y depend on the amount of memory, and brand, I do not know many brands of
external storage devices but Western Digital (usually displayed as WD on their products) seems to be
popular right now. At the moment I have a non
portable 500GB external storage dev
ice. Make sure you
look to see if the device is portable or not; portable devices will just have a USB cord built in, but non
portable devices will require an outlet. Which is bad if you are on the go.

When you plug in the external storage device via USB
port, your computer will recognize it and may
download some software which enables some extra features which includes allowing you to name your
external storage device and register it. If you want to start moving files right away, just go to

1. Start

My Computer

3. and and for instance, if you named your device, the icon may look like this:

E) "JohnsStorageDevice"


Type of Computers


Data Representation

The way that the physical properties of a medium are used to represent data. The manne
r in which data is
expressed symbolically by binary digits in a computer.

Number systems

introduced a system of numerical notation in which the first 8 numerals are substituted for the 8 notes in
the scale. Nos. are popular among 20th

cent. composers, bec
ause of the concept of 'parameters', in which
mus. sounds are regarded as the sum of several components (pitch, duration, intensity, timbre, and position
in space). What is called the Fibonacci series (each no. the sum of the previous 2) has been used to c
these components by such composers as Krenek, Stockhausen, Maxwell Davies, and Nono.

Binary System

A method of representing numbers in which only the digits 0 and 1 are used. Successive units are powers of
2. Also called binary system.

Binary to d
ecimal and Decimal to Binary Conversion

Suppose abcde is a binary number. This amounts to 1e+2d+4c+8b+16a so each digit represents the next
power of 2, just like in decimal 345 represents 5+4x10+3x100. To convert decimal to binary, keep dividing
by 2 and w
riting down the remainder eg 17: divide by 2 to get 8 with remainder 1: write down 1. Now
divide the 8 by 2 to get 4, remainder 0, add that on to get 01. Divide by 2 again: 4 divided by 2 is 2,
remainder 0 so you now have 001, divide the 2 by 2 and you get

1 and nothing left: result 1001.
Incidentally, using the divide by ten system on 345 you construct the decimal number 345 (fortunately). Try

Binary addition


Addition of binary is the computers way of counting (adding). Computers don't have the normal

system like us e.g. 1
9, they only have 'bits'

0 and 1. the rules for the of addition of binary are as follows:




1+1=0 (carry one)

1+1+carry=1 (carry one) the final carry is just placed on the left hand side of the answer

se addition and subtraction in 2's complement representation do not need to care about sign.

Binary substraction

Because this is 1+(
3) addition but it can also be changed to subtraction buy just changing the signs.
like so, 1
3). You welcome


binary system first takes the opposite of the number to subract by by inverting all bits and adding 1.
Then it adds the number to be subtracted and the inverted one.

So: 1

4 =

00000001 = 1

00000100 = 4

11111100 =

11111101 = 1 +
4 =

EBCDIC coding

coding character data ASCII is popular because of the way a computer's architecture works. A standard
ASCII keyboard displays all letters of the alphabet, but that is not enough to conform to the 32bit standard.
So other characters were imple
mented and invented, and assigned their own numerals in HEX and Binary.

Computer Software

Software is a program that enables a computer to perform a specific task, as opposed to the physical
components of the system (hardware). This includes application s
oftware such as a word processor, which
enables a user to perform a task, and system software such as an operating system, which enables other
software to run properly, by interfacing with hardware and with other software.

Practical computer systems divide

software into three major classes: system software, programming
software and application software, although the distinction is arbitrary, and often blurred. Computer
software has to be "loaded" into the computer's storage (such as a hard drive, memory, or


Once the software is loaded, the computer is able to execute the software.

Computers operate by executing the computer program.

This involves passing instructions from the application software, through the system software, to the
hardware which ulti
mately receives the instruction as machine code.

Each instruction causes the computer to carry out an operation

moving data, carrying out a computation,
or altering the control flow of instructions.

For more information about the topic Computer software
, read the full article at or see the following
related articles:

Application software

Application software is a subclass of computer software that employs the
capabilities o
f a computer directly and thoroughly to a task that the user
User interface design

interface design or user interface engineering is the design of computers, gadgets, a
ppliances, machines,
mobile communication devices, software

Originally, the word computing was synonymous
with counting and calculating, and a science that deals with the orig
inal sense of computing

Security engineering is the field of engineering dealing with the security and integrity of real
world systems. It is similar to
systems engineering .

Machine language


A set of instructions for a specific central processing unit, designed to be usable by a computer without
being translated. Also called machine code.

Assembly language

A programming language that is a close approxi
mation of the binary machine code. Also called assembly

High level languages

A computer language whose instructions or statements each correspond to several machine language
instructions, designed to make coding easier. Also known as higher
level la
nguage; higher
order language.


A compiler that allows a computer program written on one type of computer to be used on another type


One who translates orally from one language into another.

One who gives or expounds an interpretatio
n: "An actor is an interpreter of other men's words, often a soul
which wishes to reveal itself to the world" (Alec Guinness).

. A program that translates an instruction into a machine language and executes it before proceeding to the
next instruction.


One that assembles, as a worker who puts together components of an item being manufactured.

A program that produces executable machine code from symbolic assembly language.

Centralised Processing

From the word
processing perspective, in its simp
lest form the term document processing means the
production of paperwork.

Decentralised Processing

Processing occurring in a single location of facility but data is distributed to various

remote location

Distributed Processing

The first term used to des
cribe the distribution of multiple computers throughout an organization in
contrast to a centralized system. It started with the first minicomputers.

Today, distributed processing is called "distributed computing." See also

Management Information System

A computer system designed to help managers plan and direct business and organizational operations.

A management information system (MIS) provides information that organizations need to manage
themselves efficiently and effectively.

information systems

are typically computer systems
used for managing three primary co
mponents: technology, people (individuals, groups, or organizations),
and data (information for decision making).

information systems are distinct from other
information systems
, in that they are used to analyze and facilitate strategic and operational activities.

Academically, the term is commonly used to refer to the study of how individ
uals, groups, and
organizations evaluate, design, implement, manage, and utilize systems to generate information to
improve efficiency and effectiveness of decision making, including systems termed
decision support
expert systems
, and
executive information systems
.Most business schools (or colleges of business
administration within universities) have an MIS department, alongside departments of accounting, finance,
management, marketing, and sometimes others, and grant de
grees (at undergrad, masters, and


Processing modes

Data processing modes or computing modes:

Interactive computing

Interactive processing
, historically introduced as

Transaction processing

Batch processing

[Real time processing]

Data processing modes or computing modes:

Interactive computing or Interac
tive processing:

refers to software which accepts input from humans

example, data or commands. Interactive software includes most popular programs, such as word
processors or spreadsheet applications. By comparison, noninteractive programs operate w
ithout human
contact; examples of these include compilers and batch processing applications. If the response is complex
enough it is said that the system is conducting social interaction and some systems try to achieve this
through the implementation of so
cial interfaces.

Transaction processing:

is information processing that is divided into individual, indivisible operations,
called transactions. Each transaction must succeed or fail as a complete unit; it cannot remain in an
intermediate state.

Batch p

is execution of a series of programs ("jobs") on a computer without human interaction.
Batch jobs are set up so they can be run to completion without human interaction, so all input data is
preselected through scripts or command
line parameters
. This is in contrast to "online" or interactive

which prompt the user for such input.

Uniprocessor, Multiprocessor

A multiprocessor system has more than one CPU unit. A uniprocessor system has only one CPU.

Batch Processing

A technique that u
ses a single program loading to process many individual jobs, tasks, or requests for

Off Line Data Entry

Offline Data Entry

If you are the one who is looking for a quality offline data entry service, you are in the right place. Our
has a great expertise in handling all types of offline data entry works. Therefore, we will be
able to manage the entire setup efficiently to meet the requirements of our clients and customer. We also
ensure to provide high quality data accuracy for the ou
tsourced data entry projects. Once you start working
with our company, you will come to know that our company is a perfect match for all types of data entry
needs you have

line processing

The on
line data processing provides interactive computations.
Whenever transactions or input data as it
enters the system gets processed immediately. There are no provision to wait for some other data to come
in or to collect data over a period of time and submit at a time in case of Batch Processing. the on
puters processes each transaction upon receiving and results of data processing may immediately be
informed to the user of the system.

line data entry

Online Data Entry

Our company is providing an excellent guidance and support for our online data ent
ry services. We also
have a workforce, which will exceed that of the single
man workforce companies. As we have the best HR

executives, we make sure that we hire only excellent candidates who are capable of providing quality work.
We also have many advance
d technology devices such as multi sensor data processors and fast scanners,
which will help us to deliver high quality work. Combining this with the professional team of our company
will enable us to ensure quality service to our clients. Our service and
efforts are also appreciated by our
clients over the years.

Real time processing

Real time processing

In a real time processing, there is a continual input, process and output of data. Data has to be processed in
a small stipulated time period (real time)
, otherwise it will create problems for the system.

For example: assembly line robots and radar system.

batch processing

In a batch processing group of transactions collected over a period of time is collected, entered, processed
and then the batch resu
lts are produced. Batch processing requires separate programs for input, process
and output. It is an efficient way of processing high volume of data.

For example: Payroll system, Examination system and billing system.

Time Sharing Processing

In real tim
e system, a job has to be completed within fixed deadline(time allowed).

If job is not completed within the given time then system may extend t
ime for doing the operations.

In time sharing system, fixed time is given to each process and all the processes

are arranged in a queue. If
the job is not completed within the given time then it jumps to the next job leaving the previous job
unfinished. After processing to each job, it again give the same time for unfinished job.

Electronic Mail, Tele text

An Ele
ctronic Mail is what we call E
Mail for short.

A text to text connection is a connection that is the same in two books

Tele Conferencing

"A conference of people who are in different locations that is made possible by the use of such
telecommunications equ
ipment as closed
circuit television

Programming Concepts

Basic Programming Concepts

By the end of this reading you should be able to answer the following questions:

What are the three concepts fundamental to programming, regardless of the language?

tand when each of these concepts might apply when writing a program.

Name two strategies that can be helpful in planning your program.

Even though each programming language you use is unique, there are certain concepts common to all
languages, including Li
veCode's scripting language. Let's look at three of the most common concepts and
structures used in programming

: Programme definition , Characteristics of good programme

it is a show on telly Accurate and "as simple as possible but not simpler" (to quote

Albert Einstein

Programming Steps, algorithms, Flow Charts

An Algorithm is a sequence of steps involved in solving a problem.

A Flow Chart is a graphical or pictorial representation of the steps involved in solving a problem.

Introduction to Computer


computer architecture refers to the relationship between different hardware component of a computer

computer organisation refers to how operational attributes are linked togather to realised the architecture

on to microprocessors and associated components

its about introduction to computers.

It has to made from the peels of bitter oranges.

It has to have a minimum of 2.5% sugar.

An additional alcoholic base can be used if it is a neutral grain spirit.

The t
hird one is why Grand Marnier isn't a triple sec, it's added base is cognac.

Block diagram of IBM PC

Disk Operating System

Disk Operating System (specifically) and disk operating system (generically), most often reveal themselves
in abbreviated as DOGS, r
efer to an
operating system

software used in most computers that provides the
abstraction and management of
secondary storage

evices and the information on them (e.g.,
file systems

for organizing

of all sorts). Such software is referred to as a disk operatin
g system when the storage
devices it manages are made of rotating platters, such as
floppy disks

hard disks

In the early days of
computer memory

space was often limited, so the disk operating
system was an extension of the operating system. This component wa
s only loaded if needed. Otherwise,
disk access would be limited to low
level operations such as reading and writing disks at the

In some cases, the disk operating system component (or
even the operating system) was known as DOS.

Sometimes, a disk operating system can refer to the entire operating system if it is loaded off a disk and
supports the abstraction and management of disk devices. Examples include

. On the
PC compatible

platform, an entire family of operating systems was called DOS.

on. File Management

1.minimal security of data

2.there is data redundancy

3.it cannot generate queries

file management is one of the most visible component of an operating system.

computer can store information of several different types of physical me

Magnetic disk,Optical disk, and magnetic tape are the most common.

Directory Structure in DOS

I want to find a command that will copy the folder structure without the contents of the folders.

How does creating a directory structure in Dos work? does
it work as a Stack application. Last in First out

Internal and External commands of DOS
































These are those commands which are contained in command.com files of MS

These are those functions that are built into the command inter

There is no need of any external file in computer to read internal MS
DOS command.

These commands can be used as long as DOS is running on the system.

Internal commands do not vary from system to system.

These are ver, time, del, md, cd, copy con,
cls, date, vol, ren, copy etc.


These are those commands which are not in
built in MS

External commands are those which are not included in the interpreter.

There is a need of an internal file in the computer to read external MS

External command may vary from system to system. This means any two computers with same version of
DOS may have same internal commands, but may have different external commands.

These are tree, xcopy, diskcopy, more, print etc.

Batch files

A file containing data that is processed or transmitted from beginning to end.

(2) A file of operating system commands that are carried out one after the other. The operating system
interprets the commands and turns them into machine language that is execu
ted by the CPU.

Batch files are widely used to perform a series of routine file management operations such as making
backups and launching applications. In the preparation of each monthly version of this encyclopedia,
several batch files are used to combin
e and aggregate files, launch conversion programs and copy the
newly created versions into more than two dozen folders for deployment.

.BAT, .CMD or .SH File Extensions

Windows batch files use a .BAT or .CMD file extension, the latter officially called a W
indows "command
script." In the Mac and Unix/Linux worlds, batch files are "shell scripts" and use a .SH extension. See

Configuration files

A file that contains data about a specific user, program, computer or file. Used for a myriad of reasons,
tion files are generally read at startup by the operating system as well as by applications in order

to customize the environment for the user. In the Windows world, especially the earlier versions of
Windows, .INI (initialization) files have been used. In

Java, configuration data are stored in properties files.
The Registry is also a storehouse of configuration data, which is widely used.

Configuration files typically store data in a key=value structure, which means each item of data (the key)
has a name,
and its value is its contents. For example, defaultFont=Arial.

System files

An executable file (in machine language) that is part of the operating system or other control
program. The term may also refer to a configuration file used

by such programs. See

system disk

system folder


output microfilm


Because it can be.


On drawings, abbr. for “system.”


(EXEcutable file) Pronounced "ex
ee file." The name given to a program in machine language that is ready
to run in DOS, Windows, OS/2 and VMS. The name comes from the .EXE extension at the end of the
program name; for example: XYZ.EXE. In DOS, if a progra
m fits within 64K, it may be a COM file; for
example: XYZ.COM.

TXT files

A text file (sometimes spelled "textfile": an old alternate name is "flatfile") is a kind of
computer file

that is
ured as a sequence of

electronic text
. A text file exists within a
computer fil
e system
. The end
of a text file is often denoted by placing one or more special characters, known as an

after the last line in a text file.

"Text file" refers to a type of conta
iner, while
plain text

refers to a type of content. Text files can contain
plain text, but they are not limited to such.

At a generic level of description, there are two kinds of computer files: text
files and
binary files

Programming Logic & Design Techniques :

program calculates

nothing in electronic

logic circuits.

relay logic circuits often use solenoids as the electromagnetic coils of the relays.

Programme development

May refer to the coding of an individual software program or to the creation on an entire information
system and all related softw
are. See

system development life cycle

level Programming language

1:A computer language consisting of

mnemonics that directly correspond to machine language instructions;
for example, an assembler that converts the interpreted code of a higher
level language to machine

2 :Pa low
level programming language is a
programming language

that provides little or no

from a computer's
instruction set architecture

Generally this refers to either
machine code

. The word "low" refers to the small or nonexistent amount of

between the language

and machine language; because of this, low
level languages are sometimes described as being "close to the

level languages can be converted to machine code wit
hout using a compiler or interpreter, and the
resulting code runs directly on the processor. A program written in a low
level language can be made to run
very quickly, and with a very small memory footprint; an equivalent program in a high
level language w
be more heavyweight. Low
level languages are simple, but are considered difficult to use, due to the
numerous technical details which must be remembered.

level languages

1:A computer language whose instructions or statements each correspond to se
veral machine language
instructions, designed to make coding easier. Also known as higher
level language; higher
order language.

2:A high
level programming language is a
programming language

with strong

from the details
of the
. In comparison to
level programming languages
, it may use
natural language

elements, be easier to use, or may automate (or even hide entirely) significant areas of computing systems
(e.g. memory management), ma
king the process of developing a program simpler and more
understandable relative to a lower
level language. The amount of abstraction provided defines how "high
level" a programming language is.

The first high
level programming language designed for computers was
, created by

However, it was not implemented in his time, and his original contributions were largely isolated
from other developments (it influenced
Heinz Rutishauser
's language "Superplan").



is one of the 4 main

programming paradigms
. Its

theory of computation

is based

first order logic

Programming languages

such as




implement it.

A form of logical sentences commonly found in logic programming, but not exclusively, is the

Horn clause
An example is:

p(X, Y) if

q(X) and r(Y)

Some logic programming languages accept other logical sentences, such as the "choice" sentence in

et programming

Logical sentences can be understood purely

. They can also be understood


reduction procedures

: to solve

p(X, Y), first solve

q(X), then solve


The programmer can use the declarative reading of logic programs to verify their correctness. In addition,
the programmer can use the known behaviour of the program executor to d
evelop a procedural
understanding of his program. This may be helpful when seeking better execution speed. However, many

program transformation

techniques have been develop
ed to transform logic programs
automatically and make them efficient.

programming techniques

There are 2 major goals easily to say than done in any programming:

The software works as desired

The software is maintainable

Any technique that can lead you to

those 2 goals are superbly good.


programming tool


software development tool

is a





software developers

to create, debug, maintain, or otherwise support other programs and applications. The term usually refers

relatively simple programs that can be combined together to accomplish
a task, much as one might use
multiple hand


to fix a physical object.

, programme maintenance


The updating of computer programs both by error correction and by alteration of programs to meet
ng needs.

Updating programs to reflect changes in the organization's business or to adapt to new operating
environments. Although maintaining old programs written by ex
employees is often much more difficult
than writing new ones, the task is usually give
n to junior programmers, because the most talented
professionals don't want the job.

The Real World of Program Maintenance

Undocumented programs are a
huge problem, and this commentary from PROCASE Corporation gets right
to the point. The company's SMARTsystem program created a flowchart from programming source code in
order to make it understandable.

Techniques of programming

There are 2 major goals e
asily to say than done in any programming:

The software works as desired

The software is maintainableAny technique that can lead you to those 2 goals are superbly good


A predetermined procedure or ordered sequence of instructions for carrying
out an operation in
a finite number of steps. Computer programming involves designing such procedures since computing is
precisely the automation and execution of algorithms. Moving the decimal point for multiplication or
division by multiples of 10 is a c
ommonly used algorithm. The Euclidean algorithm is a method for finding
the greatest common divisor of two numbers by continued subtraction.

The origin of the term is from the name of an Arab mathematician, al
Kuwārizmi (c.830), who wrote an
extensive acc
ount of the Hindu system of numerals and numeration from which our current system evolved.
Writing numbers and performing calculations using Hindu numbers became known through his account as
'algorismi', and competitions were held between the abacists, who

favoured the abacus for calculations,
and the algorists, who preferred pencil
paper calculations. To use an algorithm, perhaps as a rule of
thumb, need not require an understanding of why it works, and algorithmic thinking can be a term used
ely. Yet making some mental operations a matter of mechanical routine can free the conscious
attention for other more demanding matters.


Graphical representation of a process, such as a manufacturing operation or a computer
operation, indica
ting the various steps taken as the product moves along the production line or the problem
moves through the computer. Individual operations can be represented by closed boxes, with arrows
between boxes indicating the order in which the steps are taken and

divergent paths determined by
variable results.



is an informal


description of the operating principle of



or other


It uses the structural conventions of a

programming language
, but is intended for human reading rather
than machine reading. Pseudocode typically omits details that are not essential for human understanding
of the algorithm, s
uch as

variable declarations
, system
specific code and some

. The
programming l
anguage is augmented with

natural language

description details, where convenient, or with

compact mathematical notation. The purpose of using pseudocode is that it is easie
r for people to
understand than conventional programming language code, and that it is an efficient and environment
independent description of the key principles of an algorithm. It is commonly used in textbooks and
scientific publications that are documen
ting various algorithms, and also in planning of computer program
development, for sketching out the structure of the program before the actual coding takes place.

No standard for pseudocode syntax exists, as a program in pseudocode is not an executable pr
Pseudocode resembles, but should not be confused with

skeleton programs
, including

dummy code
, which
can be


without errors.



Unified Modeling Language

(UML) charts can be thought of
as a graphical alternative to pseudocode, but are more spacious on paper.

Introduction to programming in QBASIC

This is a gentle

introduction to programming using the computer programming


(sometimes called

QBasic). This introduction is used for a course in computer literacy for
students of all majors. Its goal is to show what programming is about using the fundament
al features of

These are interactive lessons. Each chapter consists of about 20 web pages, and is about the equivalent of
one classroom lecture. At the bottom of each page is a question on the material on that page. Answer the
question before movin
g on to the next page.

Nobody learns programming just by reading. Copy the example programs into QBasic, run them, modify
them, and play with them

structured programming


Structured programming

is a

programming paradigm

aimed on improving the clarity, quality, and
development time of a

computer program

by making extensi
ve use of





while loops

in contrast to using simple tests and jumps such as the


which could le
ad to "
spaghetti code
" which is both difficult to follow and to maintain.

It emerged in the 1960s

particularly from work by Böhm and Jacopini,

and a famous letter,

Go To
Statement Considered Harmful
, from

Edsger Dijkstra

in 1968

and was bolstered theoretically by

structured program theorem
, and practically by the emergence of languages such as


suitably rich

control structures

, Need of structured programming Development of programs in QBASIC.



k Beginners All purpose Symbolic Instruction Code) is an




for a
variant of the

BASIC programming language

which is based on

. Code entered into the IDE is
compiled to an intermediate form, and this intermediate form is immediately interpreted on demand within
the IDE.

can run under nearly all versions of


, or through




For its time, QBasic provided a state
art IDE, including a


features such as on
fly expression evaluatio
n and code modification.

Like QuickBASIC, but unlike earlier versions of Microsoft BASIC, QBasic is a

language, supporting constructs such



while loops

Line numbers
, a
concept often associated with BASIC, are supported for compatibility, but are not considered good
according to whom?

having been replaced by descriptive

line labels
QBasic has limited support for
defined data types (
), and sev
eral primitive types used to contain strings of text or numeric