Module 1 -

learnedmooseupvalleyElectronics - Devices

Nov 7, 2013 (4 years and 7 months ago)


Computer System Organization

Computer contains input devices (keyboard,
mouse, A/D (analog
digital) converter, etc.),
a computational unit, and output devices
(monitors, printers, D/A converters). The
computational unit is the computer's heart, and
usually consists of a central processing unit
(CPU), a memory, and an input/output (I/O)

Characteristics of Computer



The speed of a computer is incredibly faster
than what man can possibly record or calculate



A computer system can store a large
amount of data in a systematic manner.

Accuracy and Reliability


Inspite of high speed, the
computers are quite accurate and reliable in their
calculations. the accuracy of operation of a computer
is always 100%.



Once the process has been initiated,
computer is quite capable of functioning
automatically. it does not require a prompt from an
operator at each stage of the process.



Is capable of operating at
exactly the same level of speed and accuracy even if
it has to carry out the most voluminous and complex
operations for a long period of time.

Scientific Approach


The entire approach to solving
problems is highly scientific, objective and
sequentially carried out, leaving no room for
emotional & subjective evaluations made by man.



The wide use of computers in so many
areas in day
day life is an ample evidence of its

Uses of Computer

Word Processing


Word Processing software
automatically corrects spelling and grammar


You can diagnose diseases. You can learn
the cures.

Mathematical Calculations


Computing speeds of
over a million calculations per second



All financial transactions are done by
computer software. They provide security, speed and



One can book air tickets or railway tickets
and make hotel reservations online.



Online exams and get instant

Generation of Computer

First Generation (1940


The first computers
used vacuum tubes for circuitry and magnetic drums for

Second Generation (1956


replaced vacuum tubes and ushered in the second
generation of computers.

Third Generation (1964


The development of
the integrated circuit was the hallmark of the third
generation of computers.

Fourth Generation (1971


microprocessor brought the fourth generation of
computers, as thousands of integrated circuits we
rebuilt onto a single silicon chip.

Types of Computer



Computer that uses the continuously
changeable aspects of physical phenomena such as
electrical, mechanical, or hydraulic quantities to model
the problem being solved.



Computer with a microprocessor
as its central processing unit.



A class of multi
user computers
that lies in the middle range of the computing
spectrum, in between the largest multi
user systems
and the smallest single
user systems.



Are computers used mainly by large
organizations for critical applications, typically bulk
data processing.

Super computer


A mainframe computer that is
among the largest, fastest, or most powerful of those
available at a given time.



Computers that exhibit features of analog
computers and digital computers.

Input Device


A hardware device that sends
information into the CPU.



An input device which uses an
arrangement of buttons or keys.


A pointing device.



A pointing device consisting of a ball.



An input device consisting of a stick.

Digitizing Tablet


A computer input device that allows
one to hand
draw images and graphics.



Device that optically scans images, printed
text, handwriting, or an object, and converts it to a
digital image.

Digital Camera


A camera that takes video or still
photographs, or both, digitally by recording images
via an electronic image sensor.



Type of font capable of recognition using
magnetically charged ink.



The mechanical or electronic translation of
images of handwritten, typewritten or printed text
into machine
editable text.



The process of capturing human
marked data
from document forms.

Code Reader


An electronic device for reading
printed barcodes.

Voice Recognition


Converts spoken words to text.

Light Pen


A small, photosensitive device connected
to a computer and moved by hand over an output .

Touch Screen


A monitor screen that can detect and
respond to something, such as a finger or stylus,
pressing on it.

Output Deice


Any peripheral that receives and displays

output from a computer.



A device that displays images or symbols
generated by computers

Characteristics of Monitors


T he number of distinct pixels in each
dimension that can be displayed.

Dot Pitch

Is a specification for a computer display
that describes the distance between dots (sub
of the same color on the screen.

Refresh Rate

Is the number of times in a second
that display hardware draws the data.


Is measured diagonally from one corner of the
screen to another.

Types of Monitors


Is a vacuum tube containing an electron gun
and a fluorescent screen, with internal or external
means to accelerate and deflect the electron beam,
used to create images in the form of light emitted
from the fluorescent screen.

Flat Panel

encompass a growing number of
technologies enabling video displays that are lighter
and much thinner than traditional television and video

LCD Monitor/screen

Is a thin, flat panel used for
electronically displaying information such as text,
images, and moving pictures.


A printer is a peripheral which produces a hard copy
of documents stored in electronic form.


Daisy Wheel

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

Dot Matrix

Is a type of printer with a head that runs
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.


Is a type of printer that reproduces a digital
image by propelling variably
sized droplets of liquid or
molten material (ink) onto a page.


Is a common type of printer that rapidly
produces high quality text and graphics on plain

Line Printer

Is a form of high speed impact printer in
which one line of type is printed at a time.


Is a vector graphics printing device to print
graphical plots, that connects to a computer.

Sound Card

Is a computer expansion card that
facilitates the input and output of audio signals to and
from a computer under control of computer programs.


An output device that produce sound.


Primary Memory

Storage Capacity


Volatile Memory

Primary Devices : RAM, ROM

Secondary Memory

Storage Capacity


Volatile Memory

Secondary Devices : Floppy
Disk, Hard Disk

Storage Devices

Magnetic Tape, Cartridge Tape

Storage Medium that
is accessed and processed sequentially. Advantages:
Low cost, Portable. Disadvantages: Slow, no direct
process, must be labeled, environment problem.

Hard disk drives

volatile storage device.
Advantages : Unlimited Storage Capacity, Direct
Access, Portable, High data transfer rate, less
vulnerable to data corruption. Disadvantages :

Floppy Disks


A data storage medium that is
composed of a disk of thin, flexible ("floppy")
magnetic storage medium encased in a square or
rectangular plastic shell. Advantages: Low cost,
Portable, easy to use. Disadvantages: Unreliability


A Compact Disc (CD) is an optical disc used
to store digital data. Advantages: Low cost,
Portable. Disadvantages: Limited space


Is a standard digital format for storing
video on a Compact Disc. Advantages: Low cost,
Portable. Disadvantages: Limited space.


A rewritable optical disc format used to
store digital data.

Zip Drive

Is a medium
capacity removable disk
storage system


Also known as Digital Versatile Disc or
Digital Video

Disc, is an optical disc storage
media format. Its main uses are video and data


Is a rewritable optical disc.


Is a general term primarily used for digitally
stored data such as computer programs and
other kinds of information read and written by

System Software

Computer software designed
to operate the computer hardware and to provide
and maintain a platform for running application.

Application Software

Computer software
designed to help the user perform a particular

Operating System (OS)

Operating System acts as an interface between
hardware and user. It is responsible for the
management and coordination of activities and
the sharing of the resources of a computer.

Single user OS


Usable by a single user at a time.

Multi user OS


The operating systems of this type
allow a multiple users to access a computer system

Real time OS


It is a multitasking operating system
that aims at executing real
time applications using
specialized scheduling algorithms.

Timesharing OS


Is sharing a computing resource
among many users by means of multiprogramming
and multi
tasking By allowing a large number of users
to interact concurrently with a single computer

Batch processing OS


Execution of a series of
programs ("jobs") on a computer without manual

Multiprocessing OS


Use of two or more central
processing units (CPUs) within a single computer

Multiprogramming OS


Allocation of a computer
system and its resources to more than one concurrent
application, job or user.

Multitasking OS


A method by which multiple tasks,
also known as processes, share common processing
resources such as a CPU.

Distributed processing


Distributed processing
implies that processing will occur on more than one
processor in order to complete a transaction.

Programming Language

programming language

is an artificial language that can
be used to instruct a computer to do a particular task.

Machine Language :
Machine language is the language of '0'
and '1' which is actually understood by the machine and thus
no translator is required. But is not in readable form for
human being.

programming language

is an artificial language that can
be used to instruct a computer to do a particular task.

Machine Language :
Machine language is the language of '0'
and '1' which is actually understood by the machine and thus
no translator is required. But is not in readable form for
human being.

Assembly Language : Assembly Language is language which
is in symbolic codes for ex. If instruction of adding two
numbers has to be written 'ADD' symbol can be used in this
program can be written. Thus assembly language are a little
easier to code for human beings but a program called
assembler is needed to translate this symbolic code in
machine code.

High Level Languages

: High level languages
are in easily readable form and a program
called compiler is used to translate the
program into machine code.


: It is a translator program which is
used to translate high level language program
to machine language program. Thus high
level language program acts as input for the
compiler and the machine language comes as
output from it. After compilation of the source
program, the resulting object program is
saved for further use, and thus repeated
compilation is not necessary


: It is also a type of translator program.
Unlike Compiler, which gives a machine code program
as a result, Interpreter only results in execution of
program if program's syntax is right but since the
resultant object program is not saved for further use
thus interpreter is needed every time the program is

Interpreter takes one statement of source program,
translates it into object program instruction and then
immediately executes the resulting machine language
instruction while compiler translates the entire source
program into object program and is then not involved
into the execution.

Assembler :

Assembler is a translator program which
translates assembly language program into machine
language program. Along with translating, it also assembles
the machine language program in the main memory of the
computer and thus make it ready for the execution.


Scans complete
program and then
translate it into
machine code

When all the syntax
errors are removed,
only then program can
be executed

Slow Debugging

Fast Execution


Scan a single line,
translate it, and then
move to the next line

Every line is checked
for the syntax error
and then translated
into the machine code

Fast Debugging

Slow Execution