THIS TEKK ABOUT FOC

1. Computer:
 A computer is an electronic device that accepts data
from the user, processes it, produces results, displays
them to the users, and stores the results for future
usage.
usage.
 Data is a collection of unorganized facts & figures
and does not provide any further information
regarding patterns, context, etc. Hence data means
"unstructured facts and figures".
 Information is a structured data i.e. organized
meaningful and processed data. To process the data
and convert into information, a computer is used

2. Functions of Computers
Receiving Input
Data is fed into computer through various input
devices like keyboard, mouse, digital pens, etc. Input
can also be fed through devices like CD-ROM, pen
drive, scanner, etc.
Processing the information
Operations on the input data are carried out based on
the instructions provided in the programs.
Storing the information
Storing the information
After processing, the information gets stored in the
primary or secondary storage area.
Producing output
The processed information and other details are
communicated to the outside world through output
devices like monitor, printer, etc.

3. The characTerisTics of The compuTer:
1.Speed
A computer works with much higher speed and accuracy
compared to humans while performing mathematical
calculations. Computers can process millions (1,000,000)
of instructions per second. The time taken by computers
for their operations is microseconds and nanoseconds.

4. 2.Accuracy
Computers perform calculations with 100% accuracy. Errors
may occur due to data inconsistency or inaccuracy.
3.Diligence
A computer can perform millions of tasks or calculations
with the same consistency and accuracy. It doesn’t feel
any fatigue or lack of concentration. Its memory also
makes it superior to that of human beings.
4.Versatility
Versatility refers to the capability of a computer to
Versatility refers to the capability of a computer to
perform different kinds of works with same accuracy and
efficiency.
5.Reliability
A computer is reliable as it gives consistent result for
similar set of data i.e., if we give same set of input any
number of times, we will get the same result.
6.Automation
Computer performs all the tasks automatically i.e. it
performs tasks without manual intervention.

5. 7.Consistency
Computer is a consistent machine, it means that computer
never gets tired of working more. You can use computer to
perform your task without any error for any number of hours,
any number of hours means you can use your computer
system continuously for 24 hours a day and 365 days a year.
8.Storage Capacity
Computer can store huge amount of data in a small sized
storage disk such as hard disk, CD, DVD, PenDrive, memory
card etc.
9.Flexibility
9.Flexibility
Flexibility means that a computer can work in many areas
like you can use your computer system to:
• Watch movies or videos
• Listen sounds or music
• Play games
• See pictures
• Write textual documents and save

6. Computer systems consist of three components as
shown in below image:
1. Input unit
2. Central processing unit
3. Output unit

7. Input unit:
The main function of input devices is to direct
commands and data into computers.
Computers then use their CPU to process this data
and produce output.
Example: Mouse , Keyboard, Microphone etc.
Output Unit:
Final component of a computer system is the output
Final component of a computer system is the output
unit.
After processing of data, it is converted into a
format
which humans can understand.
Examples of output devices include monitors,
screens, printers and speakers.

8. Central Processing Unit (CPU)
 After receiving data and commands from users, a
computer system now has to process it according to the
instructions provided. Its done by Central Processing Unit
 Central Processing Unit (CPU) is called "the brain of
computer“
 It consists of two components: Arithmetic Logic Unit
(ALU), and Control Unit. But Main Memory also come hand
in hand

9. Arithmetic Logic Unit (ALU):
Data entered into computer is sent to RAM, from where it is
then sent to ALU, where rest of data processing takes place.
All types of processing, such as comparisons, decision-making
and processing of non-numeric information takes place here
and once again data is moved to RAM.
Control Unit:
 As name indicates, this part of CPU extracts instructions,
performs execution, maintains and directs operations of
entire system.
entire system.
Functions of Control Unit:
 It controls all activities of computer
 Supervises flow of data within CPU
 Directs flow of data within CPU
 Transfers data to Arithmetic and Logic Unit
 Transfers results to memory
 Fetches results from memory to output devices

10. Memory/Storage Unit:
When we enter the data into the computer using an
input device,
 the entered information immediately gets saved in
the memory unit .
 Intermediate results of processing
 Final results of processing, before they are
released to
an output device
an output device
Two Types of Storage:
 Primary Storage
 Secondary Storage

11. Primary storage
 Used to hold data, intermediate results, and
results of ongoing processing of job(s)
 Fast in operation
 Small Capacity
 Expensive
 Volatile (looses data on power dissipation)
Secondary storage
 Slower than primary storage
 Large Capacity
 Lot cheaper that primary storage
 Retains data even without power
 Permanent Storage and Portable(carriable)

12. Laptops:
 A Laptop computer (also called portable computer or notebook
computer in English) is designed with portability in mind.
 It is briefcase style with a foldout screen with a clam shell form
factor, suitable for mobile use and with a miniature keyboard
 The laptops are more expensive because the technology to be
more compact and they are more difficult to design and
more compact and they are more difficult to design and
manufacture.
 The components of a laptop are built-in monitor;
keyboard touch-pad (which replaces the mouse), USB,
graphics card and sound cards as well as high-capacity batteries
that are made to keep the laptop power for a long period of
time.

13. Personal computers
 The PC is a general-purpose, cost-effective computer that
stands for the personal computer.
 it is referred to as a single-user computer and a desktop that is
designed to be used by a single end-user.
 PC contains a keyboard, mouse, monitor, and system unit. Most
of the personal computers have an Internet or a network
connection, including ports for connecting peripheral devices
like external hard drives, scanners, printers, digital cameras,
and more.
and more.
PCs have various parts, which are as follows:
 Computer case
 Power supply
 CD/ DVD
 drives/writers
 Hard disk(s)
 ROM/RAM

14. Work stations
workstation, a high-performance computer system that is
basically designed for a single user and has advanced
graphics capabilities, large storage capacity, and a
powerful central processing unit.
Advantages of workstation
High performance:
High performance:
This type of computers can give more performance than a
normal computer. It is best suited for rendering complex
graphics, financial analysis, and digital content creation.
Large memory:
A workstation has a larger memory than a desktop PC. It has about
twice the memory as compared to laptops, tablets, smartphone or
other devices.

15.  Multiple processors support:
A workstation has multiple processors attached to
it. By using multiprocessors you can run multiple
applications at a time without any issue. Your
system will not slow down by opening multiple
applications.
 Operating system:
Unlike PC’s , they work on server version of
Unlike PC’s , they work on server version of
windows, like Mac OS , LINUX or UNIX operating
system. Support multiuser environment.
 Expansion slot:
It has more expansion slots then PC’s providing
greater flexibility of supporting additional
functionality. Like it has 2 or more NICs plugged in.

16. Mainframe computer
 A mainframe computer is a large computer capable
of rapidly processing massive amounts of data at high
speeds.
 Mainframe computers by definition are computers
that have a lot of memory and processors, so they
can do billions of transactions and simple calculations
in real time.
 A mainframe is used for transaction servers,
commercial databases, and applications that need
commercial databases, and applications that need
ample reliability, security, and speed.
Component of Mainframe Computers:
1.Consoles: One or more console terminals connected
to host computer to monitor’s performance and to
perform other activities.
2.Storage devices: For, larger volume data storage,
users connect several magnetic disk and tape library
(located in system room ) directly to back end
computer

17. 3. User Terminal: these serves as access stations, terminals can
be at different locations may be at user room , or at different
location , Many user can use same system simultaneously.
4. Output devices: For hard copy outputs many printers , plotters
etc can be connected to back-end , located at user room as it’s
used by the user.
Minicomputer
 A minicomputer is also known as mini. It is a class of small
 A minicomputer is also known as mini. It is a class of small
computers that was introduced into the world in the mid-1960s.
 A minicomputer is a computer which has all the features of a large
size computer, but its size is smaller than those.
 Minicomputer can support multi-users at a time or you can say that
minicomputer is a multiprocessing system.
 The types of minicomputer are- tablet PC, Desktop minicomputers,
cell phones, notebooks, high-end mP3 players, etc.
 These minicomputers can do time-sharing, batch processing, and
online processing.

18. Super computer
supercomputer, any of a class of extremely powerful computers.
The term is commonly applied to the fastest high-performance
systems available at any given time.
The cost of a supercomputer is fairly high, ranging from two lakh
dollars to more than one hundred million dollars.
Ex: PARAM 8000 , PARAM 8600 , PARAM 9000
The uses are as follows:
• Supercomputers are used in scientific research fields. In
addition, the supercomputers are used for weather forecasting,
addition, the supercomputers are used for weather forecasting,
meteorology, nuclear energy research, and so on
• The military uses supercomputers to test new aircraft, tanks,
and missiles. Apart from this, they use them to analyze the
effect on soldiers and fights as well as are used to encrypt data.
• Scientists use them to investigate the impacts of nuclear weapon
explosions.
• Hollywood uses supercomputers to create animations.
• Supercomputers are used in entertainment for online gaming.
• When a game has a large number of participants,
supercomputers assist in stabilizing the game’s performance.

19. There are three types of programming languages:
 Machine language
 Assembly language
 High-level language.
Machine language:
• It is Machine code language of computers.
• It is read by the computer's central processing unit
(CPU),
• It is composed of digital binary numbers and looks
like a very long sequence of zeros and ones.
• Ex:01001000

20. Features of Machine Languages:
1. Machine understandable: Computer can execute
program written in this language at a greater speed
as, it can understand the language and can use it
without help of any translator.
2. Machine Dependent: It differs from one system to
another, Even after becoming proficient in machine
language of one type of computer , if company
language of one type of computer , if company
want to change to another type, programmer have
to learn new machine language.
3. Difficult to program: Programmer need to memories
all the binary codes of all numbers and letters.
4. Error prone: As binary codes difficult to memories
so , more errors are possible and detecting ,
correcting and modifying is also difficult.

21. Assembly Language
Assembly language is a bit more user-friendly than
machine-level language but more difficult than high-
level language
Type of low-level computer programming
language consisting mostly of symbolic equivalents of a
particular computer’s machine language.
Example : ADD , SUB ,SET
Assembler:
An assembler is a type of computer program that interprets
software programs written in assembly language into
machine language, code and instructions that can be
executed by a computer.

22. Advantages of using assembly language are
 It requires less memory and execution time
 It allows hardware-specific complex jobs in an easier way
 It is suitable for time-critical jobs
Higher level language
 Such languages are considered high-level because they are closer
to human languages and further from machine languages.
A high-level language (HLL) is a programming language such as C,
 A high-level language (HLL) is a programming language such as C,
FORTRAN, or Pascal that enables a programmer to write programs
that are more or less independent of a particular type of computer
 Compiler or interpreter is used to convert high level language to
machine language

23. Compiler:
• A compiler translates the entire source code in a single run.
• program run time is more and occupies a larger part of memory.
• compiler goes through the entire program and then translates the
entire program into machine codes.
• Faster in executing program
• C, C++, C#, etc are programming languages that are compiler-based.
Interpreter:
Interpreter:
Translates the program one statement at a time.
Considering it scans code one line at a time, errors are shown line by
line.
Due to interpreters being slow in executing the object code, it is
preferred less
Python, Ruby, Perl, SNOBOL, MATLAB, etc are programming languages
that are interpreter-based.

24. High level language has following advantages :
 Easy to Use and Understand : High level language uses English
like words and they are closer to natural language which makes easy
to learn and understand.
 Machine Independent : program written using high level
language can be executed on any type of computer with little or no
modification at all.
 Debugging is Easy : High level language makes easier to write
and debug a program and gives the programmer time to think about
and debug a program and gives the programmer time to think about
overall logic rather than thinking about program code.
 Easy to Maintain Program : Modification and maintenance of
program written in high level language is easy compared low level
language

25. High level language has following disadvantages :
 Poor Control on Hardware: Since high level languages are away
from hardware and programmer does not need to be aware of
hardware, accessing and controlling hardware directly is difficult.
 Slow Execution: Program written in high level language need to
be translated to machine language. This translation process increases
the execution time of program.

26. Generation
(period)
Key Hardware
Technology
Key Software
Technology
Key
Characteristics
Some
Represent-
ative
System
First
(1942-1955)
• Vacuum tubes
•Electromagneti
c relay memory
Punched cards
•Machine and
Assembly
languages
Mostly
• Bulky in size
• Highly unreliable
• Limited
commercial
• ENIAC
• EDVAC
• EDSAC
UNIVAC I
c relay memory
• Punched cards
secondary
storage
languages
•Mostly
scientific
applications
Limited
commercial
use and costly
• Difficult
commercial
production
• Difficult to use
EDSAC
• UNIVAC I
• IBM 701

27. Generation
(period)
Key Hardware
Technology
Key Software
Technology
Key
Characteristics
Some
Represent-
ative
System
Second
(1955-1964)
•Transistors
• Magnetic
cores
memory
• Magnetic
tapes
• Disks for
•Batch
operating
system
• High-level
programming
languages
• Scientific and
•Faster, smaller,
more reliable and
easier to
program than
previous
generation
systems.
• Honeywell
400
• IBM 7030
•CDC 1604
• UNIVAC
LARC
• Disks for
secondary
Storage
• Scientific and
commercial
Applications
systems.
•Commercial
production was still
difficult and
Costly.

28. Generation
(period)
Key Hardware
Technology
Key Software
Technology
Key
Characteristics
Some
Represent-
ative
System
Third
(1964-1975)
•ICs with SSI and
MSI technologies
• Larger
magnetic
cores memory
• Larger
capacity
disks and
•Timesharing
operating
system
•Standardizati
on
of high-level
programming
languages
• Faster, smaller,
more reliable,
easier and
cheaper to produce
• Commercially,
easier to use , and
easier to upgrade
than previous
• IBM
360/370
• PDP-8
• PDP-11
• CDC 6600
disks and
magnetic tapes
secondary
storage
•Minicomputers;
upward
compatible
family
of computers
languages
•Unbundling
of
software from
hardware
than previous
generation
systems.
• Scientific ,
commercial
and interactive
online
Applications.

29. Generatio
n
(period)
Key Hardware
Technology
Key Software
Technology
Key
Characteristics
Some
Represent-
ative
System
Fourth
(1975-
1989)
• ICs with VLSI
technology
• Microprocessors
semiconductor
memory
• Larger capacity
hard disks as in-
built secondary
storage
•Operating
systems for PCs
with GUI and
multiple windows
on a single
terminal screen
•Multiprocessing
OS with
concurrent
• Small,
affordable,
reliable, and
easy
to use PCs
• More powerful
and reliable
mainframe
systems and
• IBM PC and
•its clones
• Apple II
• TRS-80
• VAX 9000
• CRAY-1
• CRAY-2
• CRAY-X/MP
storage
• Magnetic tapes
and floppy disks as
portable
storage media
• Personal
computers
• Supercomputers
based on parallel
vector processing
• Spread of high
speed
computer networks
concurrent
programming
languages
• UNIX operating
system with C
programming
language
• Object-oriented
design and
programming
• PC, Network-
based, and
supercomputing
applications
systems and
supercomputers
•Totally general
purpose
machines
• Easier to
produce
commercially
• Easier to
upgrade
• Rapid software
development
possible.

30. Generatio
n
(period)
Key Hardware
Technology
Key Software
Technology
Key
Characteristics
Some
Represent-
ative
System
Fifth
(1989-
Present)
•ICs with ULSI
technology
• Larger capacity
main memory,
hard disks with
RAID support
• Optical disks as
portable read-only
storage media
•Micro-kernel
based,
multithreading,
distributed OS
• Parallel
programming
libraries like MPI
& PVM
JAVA
•Portable
computers
• Powerful,
cheaper reliable,
and easier to use
desktop machines
• Powerful
supercomputers
High uptime due
•IBM
notebooks
• Pentium
PCs
• SUN
Workstation
s
•IBM SP/2
SGI Origin
portable read-only
storage media
• Notebooks,
powerful desktop
PCs and
workstations
• Powerful servers,
supercomputers
• Internet
• Cluster computing
& PVM
• JAVA
• World Wide
Web
• Multimedia,
Internet
applications
• More complex
supercomputing
applications
supercomputers
•High uptime due
to hot-pluggable
components
• Totally general
purpose machines
• Easier to produce
commercially,
• easier to
upgrade
• Rapid software
development
possible
IBM SP/2
• SGI Origin
2000
• PARAM
10000

31. Keyboard
 Keyboard is the most common and very popular input device
which helps to input data to the computer. The layout of the
keyboard is like that of traditional typewriter, although there
are some additional keys provided for performing additional
functions.
 Keyboards are of two sizes 84 keys or 101/102 keys, but now
keyboards with 104 keys or 108 keys are also available for
Windows and Interne

32. Mouse
 Mouse is the most popular pointing device. It is a very
famous cursor-control device having a small palm size box
with a round ball at its base, which senses the movement of
the mouse and sends corresponding signals to the CPU when
the mouse buttons are pressed.
 Generally, it has two buttons called the left and the right
button and a wheel is present between the buttons

33. Joystick
 Joystick is also a pointing device, which is used to
move the cursor position on a monitor screen.
 It is a stick having a spherical ball at its both lower
and upper ends. The lower spherical ball moves in
a socket.
 The joystick can be moved in all four directions.

34. Light Pen
 Light pen is a pointing device similar to a pen.
 It is used to select a displayed menu item or draw
pictures on the monitor screen.
 It consists of a photocell and an optical system
placed in a small tube.

35. Scanner
 Scanner is an input device, which works more like
a photocopy machine.
 It is used when some information is available on
paper and it is to be transferred to the hard disk
of the computer for further manipulation.

36. Magnetic Ink Card Reader (MICR)
 MICR input device is generally used in banks as
there are large number of cheques to be processed
every day.
 The bank's code number and cheque number are
printed on the cheques with a special type of ink
that contains particles of magnetic material that
are machine readable.

37. Bar Code Readers
 Bar Code Reader is a device used for reading bar
coded data (data in the form of light and dark
lines).
 Bar coded data is generally used in labeling goods,
numbering the books, etc.
 It may be a handheld scanner or may be embedded
in a stationary scanner.

38. Speech Recognition Devices:
 Speech recognition, or speech-to-text, is the ability of a
machine or program to identify words spoken aloud and
convert them into readable text.
 Speech recognition is used to identify words in spoken
language.
 Voice recognition is a biometric technology for identifying
an individual's voice
an individual's voice
It following these four steps:
 analyze the audio;
 break it into parts;
 digitize it into a computer-readable format; and
 use an algorithm to match it to the most suitable text
representation.

39. Vision Input System:
 This allow the computer to accept input by seeing an object.
 Idea is to simulate the capability of human vision system.
Following steps to recognize given object:
1. Focus camera on given object to take its picture.
1. Focus camera on given object to take its picture.
2. It creates a digital image and feed in the system.
3. It matches this image with the pre stored image from its
database.
4. Then computer will take appropriate action.