1.
COMPUTER
Today’s century is totally, dependent on science. Computer is one of
the important will of science. Computer are the inalienable partners, their
impact is being felt daily in our homes through TV, VCR, Satellite imaging,
electronic mail etc. Computer, now a days, has become an important part of our
day to day life. Knowledge about computer to an individual (user) irrespective
of the field in which he/she works, has become essential.
The history of computers starts out about 2000 years ago, at the birth of
the abacus, a wooden rack holding two horizontal wires with beads strung on
them. In 1615, John Napier a Scottish mathematician developed a primitive form
of slide rule known as "Napier bones" and used it to calculate first
table of logarithms. It was Blaise Pascal who invented the first digital machine
in 1642. It added numbers entered with dials and was made to help his father, a
tax collector. In 1671, Gottfried Wilhelm Von Leibniz invented a computer that
was built in 1694. It could add and multiply. Thomas of Colmar created the first
successful mechanical calculator that could add, subtract, multiply, and divide.
In 1833, Charles Babbage constructed 'Analytical' Engine which could store
information, make decisions, and carry out instructions based on its
decisions.
First
Generation: First fully electronic computer ENIAC was constructed
by John P. Eckert and John W. Mauchly in 1946 which could multiply at a rate of
300 per second. It was around 1000 times faster used 19000 vacuum tubes in about
15000 square feet of floor space, consuming about 180000 watts of electrical
power.
Second
Generation: Invention of transistors made a revolution in computers. First computer
was build using transistors in place of vacuum tube in 1958 by IBM which could
perform up to 10000 calculations per second.
Third
Generation: Transistors replaced by integrated circuits (ICs). Single IC could
replace hundreds of transistors and perform millions of calculations per second.
First computer of this generation was IBM370 in 1964.
Fourth
Generation/Microprocessor: Fourth generation computers saw the advent of the
microprocessor. A microprocessor is an entire CPU on a single chip, and replaced
many of the larger components of a computer. The microprocessor allowed the
computer to find its way onto people's desktop. INTEL 1971 built first
microprocessor.
Fifth
generation: (Yet to come) A promise but not yet a reality. Genuine IQ
and parallel(Multiple task simultaneously).One step at a time. Knowledge
Processing. Merely deductivebut also inductive. KIPS but not DIPS/LIPS.
OS- PROLOG (Programming in logic). Final machine which will Talk with
human beings, See and Delivered
pictures.Hear the normal natural language.
Operating Systems (DOS/WINDOWS):
A set of programs that
controls and coordinates the use of computer hardware among various application
programs is called as Operating System. It provides an environment within which
user can execute programs. Operating system manages the resources of computer
and provides the interface between human and computer. All computers must have
an OS. The OS controls input and output; makes reasonable effort to control
peripherals; and in short acts as the interface between you the user, the
software, and the hardware.
UNIX and VAX/VMS developed for powerful machines
like workstations, mini and main frame computers are powerful but not suitable
for small machine like PC. For PC, 8-bit OS were developed like DOS, CP/M and
Apple DOS. Windows, an extension of DOS is a powerful operating systems on PC's
is user-friendly and provide graphics user interface. A computer comprises of
hardware, operating system, applications programs & users. It is the
operating system that manages all the above components.
Functions:
1. Controlling Input/Output
devices (Keyboard, Mouse, Monitor, Printer, Plotter)
2. Memory
and File storage management
3. CPU
Scheduling and controlling processes
4. Loading,
initiating, executing and supervising user applications programs
5. Handling
errors and restarting
6. Providing
command interface between user and computer system
Introduction
to DOS / WINDOWS:
Though UNIX was a powerful
operating system available, but it was not suitable for 8-bit 8086
microprocessor based Personal Computers. So there was a need for a small
operating system that could work in 640K memory (RAM).
DOS:
DOS was a variant of CP/M
(Control Program/Monitor) which ran for the first time on IBM-PC in 1981. The
different versions of MS-DOS have evolved over a period of time with Microsoft
introducing new features in each new releases. There are various versions of DOS
like MS-DOS (Microsoft), PC-DOS (IBM), Apple DOS, and Dr-DOS etc.
Basic
DOS Commands:
Directory Commands:
DIR
: To list all or specific files of any directory on a specified disk.
MD : To make directory or
subdirectory on a specified disk/drive.
CD or CHDIR : Change DOS current working directory
to specified directory on specified disk or to check for the current directory
on the specified or default drive.
RMDIR or RD : Removes a
specified sub-directory only when it is empty. This command cannot remove root
directory (C:\) or current working directory.
TREE : Displays all of the
directory paths found on the specified drive.
PATH : Sets a sequential
search path for the executables files, if the same are not available in the
current directory.
SUBST : Substitutes a
string alias for the pathname and creates a virtual drive.
File
Management Commands :
COPY : Copies one or more files from source disk/drive
to the specified disk/drive.
XCOPY : Copies files and directories, including
lower-level directories if they exists.
DEL : Removes specified files from specified
disk/drive.
REN : Changes the name of a file(Renaming).
ATTRIB : Sets or shows file attributes (read, write,
hidden, Archive).
BACKUP : Stores or back up one or more
files/directories from source disk/drive to other destination disk/drive.
RESTORE : Restores files that were backed up using
BACKUP command.
EDIT : Provides a full screen editor to create or edit
a text file.
FORMAT : Formats a disk/drive for data storage and use.
General
Commands :
TIME : sets or displays the system time.
DATE: Sets or displays system date.
TYPE: Displays the contents of at the specified file.
PROMPT: Customizes the DOS command prompt.
If a users requires help on any DOS commands he/she may
type help and command name at the command prompt.
WINDOWS:
Windows was similar to APPLE Mach operating system
interface on IBM-PC. The main features of windows are easy to use graphical user
interface (GUI), device independent graphics and multitasking support. The first
version of windows 1.0 was introduced in 1985. Windows was an application of
MS-DOS using the basic commands of DOS. WINDOWS-95 released in 1995 is a 32-bit
operating system which includes MS-DOS7.0 and takes control of computer system
after starting. WINDOWS-98, 2000 released in 1998, 2000 respt.
Features:
1. Windows
is easier to learn and use than any of its predecessors.
2. Windows
and its applications run under the PCs protected mode, which mean that one ill
behaved program cannot compromise the memory and resources of another. This
approach adds a large measure of reliability to the total operating environment.
The crash of a single errant program does not automatically crash the operating
system or any of other programs that you are running.
3. Windows
is a pre-emptive multitasking means you can comfortably type into word
processors while your database system backs up all its files. Under Windows 3.1
the typed key displays lagged behind while the backup procedure logged the
processor.
4. Windows
integrates virtually all of your computing tasks and resources like networks,
E-mail, multimedia, system administration, printing, faxing, applications into
one common user interface.
Desktop: The most visible change in Windows 98 over earlier versions of Windows is the new user interface. The full screen display you see when you boot your PC and from which you work with documents and applications.
Icon :
An
icon is a picture . Windows 98 uses small video icons that represents objects
– documents, applications, folders, devices, and computers. An icon has a text
label that further describes the object.
Selection
:
Selecting an object is pointing to it without taking any further action. To
select the object, move the mouse cursor onto the icon and press the left mouse
button once. If the currently selected object is in a group, you can change the
selected object with arrow Keys. You can change groups with Tab and Shift- Tab
keys and then use arrow keys to select an object in the selected group.
Drag
and Drop : To drag and drop an object onto another object, move the mouse cursor
onto the icon of the object to be dragged. Press down the left mouse button and
hold it down while you move mouse cursor to be destination object’s icon.
Release
the button from that position to complete the drop.
The
Right Mouse Button : If you move the mouse to almost anywhere or anything on the desktop or in
a Window and click the right mouse button, Windows 98 displays a menu with
common commands for the object. To close the menu, click the left mouse button
anywhere else on the desktop or press the keyboard’s Esc key.
Icons
on the Desktop : The upper left corner contain four icons. Those icons provides access to
your files and documents. Four icons are: My computer, Network Neighborhood,
Recycle bin and Briefcase.
My
Computer : The
"My Computer" icon on the desktops opens a view into the resources of
the local computer . The contents of the My computer Window depend on the disk
drives on your PC and the network support that is installed.
Network
Neighborhood: This icon displays the computers and shared printers connected on the
windows network.
Recycle
Bin: This
icon receives all deleted objects like files, folders, documents, applications
etc. These deleted objects can be restored back they can be permanently deleted
from the disk by choosing EMPTY RECYCLE BIN selection on the file menu.
Briefcase: The commonly used personal documents can be put or
stored in the briefcase. This briefcase can be moved to a disk or copied across
a network.
Folders:
Folders on the desktop can contain other folders,
documents, applications and shortcuts to devices such as printer. To add a
folder to the desktop, move the mouse cursor to an empty spot on the desktop and
press the right mouse button. Click the Folder command. A folder icon labelled
"New Folder" appears on the desktop.
Document:
The references to the
current documents are stored in the documents object. The documents list
includes Word processing documents, spreadsheets, database files, graphics file
etc.
Computer
Organization:
Digital
computers are electronic machines capable of performing high speed
arithmetic/logical operations and data processing. It has two major parts i)
computer hardware and ii) computer software. Computer hardware consists physical
entities like electronics circuit, transistors, capacitors etc. Computer
software is basically set of instruction code which instructs the computer to
perform a task requested by user. Computer software consists of programs which
monitor and coordinates all internal operations and provides easy interface
between computer and user.
Computer hardware, a physical entities like electronic
circuit, transistors, capacitors has four major parts i) Central processing
unit (CPU); ii) Input unit; iii) Output unit and iv) Memory. The CPU in computer
is similar to brain in human. It performs all the calculations, it execute all
the instruction received from user. It also control activity of computer.
Input devices provides the means to input to computer. Following computer
devices are commonly used by users i) Keyboard: consists array of key
switches; ii) Mouse: it is a pointing device usually contain two or three
button; iii) Joysticks: used to play games etc. Output devices are the
means by which computer present its result in human readable form.
Following computer output devices are commonly used by users i) Monitor/screen : displays
data as text or in graphics ii) Printers: allow to print the data; iii)
Plotters: used to plot the graphs. Storage devices are used to store and
retrieve data in computers. Broadly, it can be classified in two categories
i) primary storage and ii) secondary storage. Primary storage are semiconductor memories
used access data quickly and randomly (e.g. RAM, ROM). Secondary storage also
called Magnetic storage devices. These storage devices are cheaper and reliable
(e.g. Floppy disk, Hard disk, Optical disk)
Characteristics
of Computers:
1. Calculates at very high speed
2. Takes in Information & Stores for further retrieval
3. Takes in & Stores the program (set of instructions
written in the
language of computers)
4. Obeys a sequence of instructions/programs
5. Uses simple logical rules to make decisions for their
own internal control
or for the role of some external activity
6. Communicates with other systems
7. Exploits a complex internal structure of micro
electronic circuits in a variety
of ways
8. Privacy
9. Security
10. Individuality
1. Main
mode of procuring offline and online information available from databases
2. Disease-Diagnosis,
Drugs, Vaccines, Pathogenesis, Treatment, Rehabilitation updates
3. Patient
care information
4. Medical
Directories
5. Machines
are computer based
6. Thesis,
Research articles
7. Scientific
Research
8. Communications
9. Desktop
Applications
10. Business Applications
11. Word Processing
12. Banking
13. Industrial Applications
14. Space Technology
15. Transportation
16. Browsing relevant websites
for updates
Software:
1.
Not seen (in computer word) by naked eyes i.e. not present physically but
co-ordinates hardware.
2.
Logic/intelligence which run your
computer
3.
Set of the instruction (program) which carries out the job/work provided
by the user.
System
Software (Mostly operating systems)
1.
Machinery with no intelligence but tremendous capacity for hard
work.
2.
Shell-OS—interpreter-interprets
human (English) & computer (Binary) language
3.
Os commands are necessary to learn
4.
OS understand the command and converts the computer language, perform
work intended and come out with the result
5.
OS converts these results (computer language) back into ‘Human Readable
Format’ and display on monitor
6.
Pry Jobs- Machine Maintenance/Machine/Administration/Allocation of
Resources
7.
Single user Single Task ----DOS
8.
Single user Multiple task- Window
9.
Multiple user Multiple task-UNIX
10.
Networking-NetWare/Windows/UNIX/LINUX
Application
software:
1.
Does jobs like text processing, calculation, drawing a picture,
accounting etc.
2.
Graphics: Allows to draw/view/edit pictures
3.
Multimedia: Allows to hear/see/watch presentation
4.
Text processing: Standard text processing jobs like spell check,
tabulation etc.
5.
Database: Allows to store/Retrieve/Analyze/Present Information of
particular task
6.
Accounting: Maintains accounting information.
7.
Games: Allows to play interactive Videogame may contains text, visual and
audio Browser
8.
Development Tools: Allows developing software.
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