Chapter 1: Introduction to Computer 2.

Napier’s Bones - Manually-operated calculating device invented by

John Napier (1550-1617). A calculating tool that used 9 different ivory
Functions of a Computer strips or bones marked with numbers to multiply and divide. First machine
to use the decimal point.
1. Input - The data entered into a computer from the input devices. It can
be a character, word, number or image. When you enter information 3. Pascaline - Also known as Arithmetic Machine or Adding Machine.
(input) into your computer, a signal s sent to the CPU (Central Processing Invented between 1642 and 1644 by Biaise Pascal. First Mechanical and
Unit) automatic calculator.
Examples of input devices: 4. Difference Engine - Designed by Charles Babbage who is known as
“Father of Modern Computer in the 1820s. Mechanical computer which
 Keyboard
could perform simple calculations. Steam driven calculating machine
 Mouse
designed to solve tables of numbers like logarithm tables.
 Scanner
 Joystick 5. Analytical Engine - Developed by Charles Babbage in 1830.
 Camera Mechanical computer that used punch-cards as input. Capable of solving
 Mic any mathematical problem and storing information as a permanent
memory.
2. Processing - The task of performing the logical and arithmetic
operations. The CPU will perform all types of calculations based on the 6. Tabulating Machine - Invented in 1890 by Herman Hollerith.
instructions given. It is then sent to the storage unit. Mechanical tabulator based on punch cards. Tabulate statistics and record
or sort data or information. Used in the 1890 US Census.
3. Output - The process of producing the useful information for the user
after processing input data. After performing the calculations based on 7. Differential Analyzer - First electronic computer introduced in the US
given instructions, the processed data is sent to the output device. Output in 1930. An analog device invented by Vannevar Bush. Has vacuum tubes
device then translates the processed data into a form like text, image, to switch electrical signals to perform calculations. Could do 25 calculations
document that the use can understand in few minutes.
4. Storage - The process of storing instructions and data permanently. This 8. Mark I - Howard Aiken planned to develop a machine that could perform
stored data can be retrieved whenever needed. calculations involving large numbers in 1937. In 1944, Mark 1 computer
was built as a partnership between IBM and Harvard. First programmable
Examples of Storage Devices:
digital computer
 USB Flash Memory
9. Eniac (Electrical Numerical Integrator and Calculator) - Developed
 Memory Card Reader
by John W. Mauchly and J. Presper Eckert Jr. at the University of
 External Optical Drivers
Pennsylvania. Used 18,000 vacuums, punch-card input, weighted thirty
 ZIP Drive
tons and occupied a thirty by fifty-foot space
 Media Devices
 Solid State Drive Generations of Computer
History of Computers 1. First Generation Computers (1946-1959)
1. Abacus - The first computer, invented by the Chinese around 4,000 - Slow, huge and expensive.
years ago. A wooden rack which has metal rods with beads mounted on - Vacuum tubes were used as the basic components of CPU and
them. The beads were moved by the abacus operator to perform arithmetic memory.
calculations. Abacus is still used in some countries like China, Russia and - Mainly depended on batch operating system and punch cards.
Japan. - Magnetic tape and paper tape were used as output and input
devices in this generation.

2. Second Generation Computers (1959-1965)

 - Era of the transistor computers. - Many large firms & government organizations use Mainframes to
- Used transistors which were cheap, compact and consuming less run their business operations.
power - Can be accommodated in large, air-conditioned rooms because of
- Made transistor computers faster than the first-generation its size.
computers. - Mainframes can also process & store large amount of data.
- Banks educational institutions & insurance companies use
mainframe computers to store data about their customers,
students & insurance policy holders.
3. Third Generation Computers (1965 – 1971)

- Usend integrated circuits (ICs) instead of transistors.

- A single IC can pack huge number of transistors which increased
the power of a computer and reduced the cost.
- Computers also became more reliable, efficient and smaller in size. 3. Minicomputer

4. Fourth Generation Computers (1971-1980) - Used by small businesses & firms.

- Also called as “Midrange Computers”.
- Used very large scale integrated (VLSI) circuits, a chip containing - Small machines and can be accommodated on a disk with not as
millions of transistors and other circuit elements. processing and data storage capabilities as super-computers &
- These chips made this generation computers more compact, Mainframes.
powerful, fast and affordable. - Not designed for a single user.
- Used real time, time sharing and distributed operating system.
4. Microcomputer
5. Fifth Generation Computers (1980 – till date)
- Desktop computers, laptops, personal digital assistant (PDA),
- The VLSI technology was replaced with ULSI (Ultra Large-Scale tablets & smartphones
Integration). - Widely used & the fastest growing computers.
- It made possible the production of microprocessor chips with ten - These computers are the cheapest among the other three types of
million electronic components. computers.
- Used parallel processing hardware and AI (Artificial Intelligence) - The Micro-computers are specially designed for general usage like
software. entertainment, education and work purposes.
- Some of the popular fifth generation computers are Desktop,
Laptop, NoteBook, UltraBook, ChromeBook Types of Computing Environments

Four Basic Types of Computers A computer system uses many devices, arranged in different ways to solve
many problems. This constitutes a computing environment where many
1. Supercomputer computers are used to process and exchange information to handle
multiple issues.
- The most powerful computers in terms of performance and data
processing. 1. Personal Computing Environment - There is a single computer
- Specialized and task specific computers used by large system. All the system processes are available on the computer and
organizations. executed there. The different devices that constitute a personal computing
- Used for research and exploration purposes, like NASA uses environment are laptops, mobiles, printers, computer systems, scanners
supercomputers for launching space shuttles, controlling them and etc.
for space exploration purpose.
- The supercomputers are very expensive and very large in size. 2. Time Sharing Computing Environment - Allows multiple users to
- Super-computers are the fastest computers with large data storage share the system simultaneously. Each user is provided a time slice and the
capacity processor switches rapidly among the users according to it.

2. Mainframe Computer 3. Client Server Computing Environment - The client requests a

resource, and the server provides that resource. A server may serve
multiple clients at the same time while a client is in contact with only one
server. Both the client and server usually communicate via a computer
network but sometimes they may reside in the same system.

4. Distributed Computing Environment - Contains multiple nodes that

are physically separate but linked together using the network. All the
nodes in this system communicate with each other and handle processes
in tandem. Each of these nodes contains a small part of the distributed
operating system software.

5. Cloud Computing Environment - The computing is moved away from

individual computer systems to a cloud of computers. The cloud users only
see the service being provided and not the internal details of how the
service is provided. This is done by pooling all the computer resources and
then managing them using a software.

6. Cluster Computing Environment - Created by two or more individual

computer systems merged which then work parallel to each other.

Computer Hardware

-
Week 5: Computer Software Application Software - The category of programs that do something
useful for the user. It is not needed by the computer to operate but is
needed by the end-users to use. Used different kinds of computer
languages such as C#, Java, PHP, Ruby, Unity, etc.
Software - Set of instructions that tell the hardware what to do. Created
through the process of programming. For computer-based software, we call it Programs, While for mobile based
software, we call it Applications

Computer Protocol
Examples of Application Software

1. Microsoft Office
2. Playstore
3. Facebook
4. VLC
5. Firefox

Common Application Software

Types of Software 1. Word Processing - Provides for the creation of written documents.
Functions include the ability to type and edit text, format fonts and
1. System Software - Manages the hardware and create the interface
paragraphs, and add, move, and delete text throughout the document.
between the hardware and the user. This is needed in order to operate and
use our computer. 2. Spreadsheet - Provides a way to do numeric calculations and analysis.
The working area is divided into rows and columns, where users can enter
numbers, text, or formulas.
Functions of System Software
3. Presentation - Provides for the creation of slideshow presentations.
1. Managing the hardware resources of the computer. Harkening back to the days of overhead projectors and transparencies,
presentation software allows its users to create a set of slides that can be
2. Providing the user-interface components printed or projected on a screen.

3. Providing a platform for software developers to write applications. 4. Image Editing - The processes of altering images, whether they are
digital photographs, traditional photo-chemical photographs, or
illustrations.
Examples of System Software 5. Video Editing - Used for performing the post-production video editing
1. Android of digital video sequences on a non-linear editing system. It has replaced
2. Windows traditional flatbed celluloid film editing tools and analogue video tape-to-
3. Mac OS tape online editing.
4. Ubuntu Kinds of Software Uses
5. Linux
6. Fedora 1. Open Source
2. Freeware
3. Shareware
4. Commercialized / Licensed
Harmful Software

Malware (Malicious Software) - Originally created as experiments and

pranks, but eventually led to vandalism and destruction of targeted
computer machines. Malware is created for profit through forced Week 6: Operating System
advertising, stealing sensitive information, spreading email spam,
Operating System - A collection of software that manages computer
pornography, or to extort money.
hardware resources and provides common services for computer
1. Virus - Most common type of malware. A malicious program that can programs. The operating system is a vital component of the system
execute itself and spreads by infecting other programs or files. When software in a computer system. An interface between a computer user and
executed, replicates itself by modifying other computer programs and computer hardware.
inserting its own code.
Application of the OS
2. Worm - Can self-replicate without a host program. Typically spread
1. Security - By means of password and similar other techniques, it
without any human interaction or directives from the malware authors.
prevents unauthorized access to programs and data.
3. Trojan Horse - Designed to appear as a legitimate program, once
2. Control over System Performance - Recording delays between
activated following installation. The term comes from a Greek story of the
request for a service and response from the system.
Trojan War, in which the Greeks give a giant wooden horse to their foes,
the Trojans, ostensibly as a peace offering. 3. Job Accounting - Keeping track of time and resources used by various
jobs and users.
4. Spyware - Designed to collect information and data on users and
observe their activity without users' knowledge. Often hidden from the user 4. Error Detecting Aids - Production of dumps, traces, error messages,
in order to gather information about internet interaction, keystrokes, and other debugging and error detecting aids.
passwords, and other valuable data.
5. Coordination Between other software and Users - Coordination
5. Adware - Advertising banners are displayed while a program is running. and assignment of compilers, interpreters, assemblers and other software
The ads are delivered through pop-up windows or bars that appear on the to the various users of the computer systems.
program's user interface. Adware is commonly created for computers but
may also be found on mobile devices. Programming Languages

6. Zombie Computer- A computer that a remote attacker has accessed 1. Machine Language or Code - Language that is written for the
and set up to forward transmissions (including spam and viruses) to other computer hardware. Such language is affected directly by the central
computers on the Internet. processing unit (CPU) of a computer system.

7. Ransomware - Designed to infect a user's system and encrypt the data. 2. Assembly Language - It is a language of an encoding of machine code
Cybercriminals then demand a ransom payment from the victim in that makes simpler and readable.
exchange for decrypting the system's data.
3. High Level Language - Simple and easy to understand and it is similar
to English language. For example, COBOL, FORTRAN, BASIC, C, C+, Python,
etc.

4. System Language

5. Scripting Language

Data Processing - Collection, manipulation, and processing collected data

for the required use. A technique normally performed by a computer; the
process includes retrieving, transforming, or classification of information. exceeds customer expectations, reaches completion within times and cost
However, the processing of data largely depends on the following: estimates.

• The volume of data that need to be processed

• The complexity of data processing operations
• Capacity and inbuilt technology of respective computer system
• Technical skills
• Time constraints

Methods of Data Processing

1. Single User Programming - It is usually done by a single person for

his personal use. This technique is suitable even for small offices.

2. Multiple Programming - This technique provides facility to store and

execute more than one program in the Central Processing Unit (CPU)
simultaneously. Increases the overall working efficiency of the respective
computer.

3. Real-time Processing - This technique facilitates the user to have

direct contact with the computer system. This technique eases data
processing. This technique is also known as the direct mode or the
interactive mode technique and is developed exclusively to perform one
task.

4. Online Processing - This technique facilitates the entry and execution

of data directly; so, it does not store or accumulate first and then process.
Developed in such a way that reduces the data entry errors, as it validates
data at various points and also ensures that only corrected data is entered.
This technique is widely used for online applications.

5. Time-Sharing Processing - This is another form of online data

processing that facilitates several users to share the resources of an online
computer system. This technique is adopted when results are needed
swiftly. Moreover, as the name suggests, this system is time based.

6. Distributed Processing - This is a specialized data processing

technique in which various computers (which are located remotely) remain
interconnected with a single host computer making a network of computer.

Software Development
Life Cycle (SDLC) - A
process used by the software
industry to design, develop
and test high quality
software. The SDLC aims to
produce a high-quality
software that meets or