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Fundamentals of Computers
Introduction to Computers:
Computer is an advanced electronic device that takes raw data as an input from the user and processes
it under the control of a set of instructions (called program), produces a result (output), and saves it for
future use.
How does the computer work? It is as simple as making tea. To prepare tea, we add water, tea powder,
milk, and sugar. These are all considered as input. After adding all, we have to boil. That boiling is
called processing, after boiling, we get tea. That is called output.

Characteristics of computer:
 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.

 Accuracy
Computers perform calculations with 100% accuracy. Errors may occur due to data inconsistency or
inaccuracy. Computer errors caused due to incorrect input data or unreliable programs are often referred
to as Garbage-In-Garbage-Out (GIGO).

 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.

 Versatility
Versatility refers to the capability of a computer to perform different kinds of works with same accuracy
and efficiency.

 Reliability
A computer is reliable as it gives consistent result for similar set of data 1.e., if we give same set of
input any number of times, we will get the same result.

 Automation
Computer performs all the tasks automatically i.e. it performs tasks without manual intervention.

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Evolution of Computer

 Abacus
Approximately 4,000 years ago, the Chinese invented the Abacus. It was the first
machine used for counting and calculating. It is made of a wooden frame, metal
rods, and wooden beads Abacus was mainly used for addition, subtraction and later
for division and multiplication. Today, the abacus is still used widely in China and
other Asian countries to count and calculate, just as we use calculators.
 Napier’s bones
In the early 17th century, John Napier, a Scottish mathematician, invented another
calculating tool. “Napier’s bones” was based upon manipulation of rods with printed
digits. The rods were made of bone, ivory, wood or metal. The set consists of 10
rectangular blocks with multiples of a different digit on each of the four sides.

 The slide Rule

The slide Rule was invented by William Oughtred. It is based on the principle that actual
distance from the starting point of the rule is directly proportional to the logarithm of the
numbers printed on the rule. The slide rule is embodied by the two _ sets of scales that are
joined together, with a marginal space between them.

 Adding Machine-Pascaline
In 1642, at the age of 19, a French mathematician by the name of Blaise Pascal invented
the Pascaline. The Pascaline is known as the first mechanical and automatic calculator.

 Difference and Analytical Engine

In the early 1820s, an English mathematician by the name Charles Babbage designed a
computing machine called the Difference Engine. This machine was to be used in the
calculating and printing of simple math tables. In the 1830s, he designed a second
computing machine called the Analytical Engine. This machine consisted five units,
which became the basic principle for the development of modern computer. Hence Charles Babbage
is known as the "Father of Computers”.

 First Programmer-1833 AD
Lady Ada Lovelace was a first computer programmer, who designed program for
Babbage’s Analytical Engine.

 Hollerith Tabulating Machine-1890 AD

In 1889, an American named Herman Hollerith invented a counting machine to count the population
of USA. This electronic machine is able to read the information on the punched cards and
process it electronically. Herman Hollerith was the founder of the company than became
famous as IBM.

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Generations of Computers
The computer has evolved from a large-sized simple calculating machine to a smaller but much more
powerful machine. The evolution of computer to the current state is defined in terms of the generations
of computer. Each generation of computer is designed based on a new technological development,
resulting in better, cheaper and smaller computers that are more powerful, faster and efficient than
their predecessors,

First Generation Computers (1940-1956)

The first computers used vacuum tubes for circuitry(acts as switches, turning current on or off, amplification-
weak current to high) and magnetic drums for Memory.
They were often enormous and taking up entire room. First generation computers relied on machine
language. They were very expensive to operate and in addition to using a great deal of electricity,
generated a lot of heat, which was often the cause of malfunctions.

In this generation, mainly batch processing operating system was used. Punch cards, paper tape, and
magnetic tape was used as input and output devices. The computers in this generation used machine
code as the programming language. The UNIVAC and ENIAC computers are examples of first-
generation computing devices.

Advantages
 It was only electronic device.
 First device to hold memory.

Disadvantages
 Too bulky i.e. large in size.
 Vacuum tubes burn frequently.
 They were producing heat.
 Maintenance problems.

Second Generation Computers (1956-1963)

Transistors replaced vacuum tubes in the second generation of computers. Second-generation
computers moved from cryptic binary machine language to symbolic.
High-level programming languages were also being developed at this
time, such as early versions of COBOL and FORTRAN. These were
also the first computers that stored their instructions in their memory.

Advantages
 Size reduced considerably.
 The very fast.
 Very much reliable.

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Disadvantages
 They over heated quickly.
 Maintenance problems.

Third Generation Computers (1964-1971)

The development of the integrated circuit was the hallmark of the third generation of computers.
Transistors were miniaturized and placed on silicon chips, called semiconductors. Instead of
punched cards and printouts, users interacted with third generation computers through keyboard
sand monitors and interfaced with an operating system. Allowed the device to run many different
applications at one time.

Advantages
 IC's are very small in size
 Improved performance
 Production cost cheap

Disadvantages
 IC's are sophisticated.

Fourth Generation Computers (1971-present)

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits
were built onto a single silicon chip.

 The Intel 4004 chip, developed in 1971, located all the

components of the computer.
 From the central processing unit and memory to
input/output controls on a single chip.
 Fourth generation computers also saw the development
of GUIs, the mouse and handheld devices.

Fifth Generation Computers (present and beyond)

 Fifth generation computing devices, based on artificial intelligence.

 Are still in development, though there are some applications,
such as voice recognition.
 The use of parallel processing and superconductors is helping to
make artificial intelligence a reality.
 The goal of fifth-generation computing is to develop devices
that respond to natural language input and are capable of
learning and self-organization.

Different Types of Computer: Based on Working Principle, Purpose and Size

Computer can be classified in many ways. The common way is to classify the computer according to
working principle, purpose and size.

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There are different types of computer.

1. Types of Computer- Based on working Principal

a) Analog computer
b) Digital computer
c) Hybrid computer

2. Types of Computer- Based on Purpose

a) General Purpose Computer.
b) Special Purpose Computer.

3. Types of Computer- Based on Size

a) Micro Computer.
b) Mini Computer.
c) Mainframe Computer.
d) Super Computer

Types of Computer- Based On working Principal

On the basis of computer working Principle the computer can be classified into three types.
 Analog
 Digital computer
 Hybrid computer

Analog Computer : It is used to process analog data. Analog computer operates by measuring rather
than counting. An analog computer measures continuous electrical or physical magnitudes like voltage,
pressure, water flow etc. An analog computer has the ability to accept inputs which vary with time and
intensity and directly apply them to various devices which perform desired operation. It produces output
in the form of graph. These computers are mostly used in process control plants.

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Advantages of using analog computers

 It allows real-time operations and computation at the same
time and continuous representation of all data within the rage
of the analog machine.

 In some applications, it allows performing calculations

without taking the help of transducers for converting the
inputs or outputs to digital electronic form and vice versa.
The programmer can scale the problem for the dynamic range of the analog computer. It
provides insight into the problem and helps understand the errors and their effects.

Digital Computer:
a digital computer operates directly on decimal digit that represents either discrete data or symbols.
It converts the data into digits and then all operations are done on these digits at extremely fast
rates. Digit computer basically knows how to count the digits. Computers used for business and
scientific application are digital computers.
Advantages of digital computers
 It allows you to store a large amount of information and to retrieve it easily whenever You
need it.
 You can easily add new features to digital systems more easily.
 Different applications can be used in digital systems just by
changing the program without making any changes in
hardware
The cost of hardware is less due to the advancement in the IC
technology.
 It offers high speed as the data is processed digitally.
 It is highly reliable as it uses error correction codes.
 Reproducibility of results is higher as the output is not affected by noise, temperature,
humidity, and other properties of its components.

Hybrid computer:

Hybrid computer utilize the best qualities of both analog and digital computers.
They are suited for situation where digital processing of data collected in analog
form is desirable. For example: -in a hospital intensive care unit analog devices
may measure a patient’s heart function, temperature etc. these measurements may
then be converted into numbers and supplied to digital devices. Other areas are
guided missile system new aircraft design etc.

Advantages of using hybrid computers

 Its computing speed is very high due to the all-parallel configuration of the analogue subsystem.
 It produces precise and quick results that are more accurate and useful.
 It has the ability to solve and manage big equation in real-time.
 It helps in the on-line data processing.

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Types of Computer- Based on Purpose

Purpose wise computer can be classified into two types
 General Purpose Computer.
 Special Purpose Computer.

General Purpose Computer

These computers can store different programs and can thus be used in countless application. A General-
Purpose Computer can perform any kind of jobs with equal efficiency simply by changing the
application program stored in main memory.

Special purpose computer

A Special Purpose Computer is the one that is designed to perform only one special task. The program
or instructions set is permanently stored in such a machine. It does its single task very quickly and it
cannot be used for any other purpose. These computers are often used to perform specific function such
as controlling a manufacturing process or directing communications.

Types of Computer- Based on Size

 Micro Computer
 Mini Computer
 Mainframe Computer
 Super computer

Micro Computer or personal computers

a microcomputer is a computer whose CPU is a microprocessor. A microprocessor is a processor all of

whose component are on a single integrated circuit chip. Personal computers are a kind of
microcomputer. Personal computers are called so because they are designed for personal use of
individual or individual small business units’ office automation unit or professionals. PC can be used
for variety of applications like computer literacy, fun and games, business applications, programming
etc.

.

Types of Micro Computer or personal computers

 Desktop Computer.
 Laptop Computer.
 Palmtop Computer, Digital Diary, Notebook, PDAs.

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Minicomputer

They are smaller version of the mainframes. Generally, they offer the same computing power as bigger
counterparts. The most important advantage of a mini computer over the main frame is that it is cheaper
in cost smaller in size and reliable. It does not require air conditioning and can be operated in room
temperature.

Main used of these systems is in education in local government word processing etc. in business they
are being used for involving stock payroll etc. it is generally used as server system on networks with
personal computers as nodes.

Applications of minicomputers

A minicomputer is mainly used to perform three primary functions, which are as follows.

 Process control
 Data management
 Communications Portal

Mainframe Computer

Mainframe computers are designed to support hundreds or thousands of users simultaneously. They can
support multiple programs at the same time. It means they can execute different processes
simultaneously. These features of mainframe computers make them ideal for big organizations like
banking and telecom sectors, which need to manage and process high volume of data.

Mainframe computers are designed to support hundreds or thousands of users simultaneously. They can
support multiple programs at the same time. It means they can execute different processes
simultaneously. These features of mainframe computers make them ideal for big organizations like
banking and telecom sectors, which need to manage and process a high volume of data that requires
integer operations such as indexing, comparisons, etc.

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Applications of mainframe computers

 In health care, it enabled hospitals to maintain a record of their millions of patients in order to
contact them for treatment or related to their appointment, medicine updates or disease updates.

 In the field of defence, it allows the defence departments to share a large amount of sensitive
information with other branches of defence.

 In the field of education, it helps big universities to store, manage and retrieve data related to
their courses, admissions, students, teachers, employees and affiliated schools and colleges.

 In the retail sector, the retail companies that have a huge customer base and branches use
mainframe computers to handle and execute information related to their inventory management,
customer management, and huge transactions in a short duration.

Super Computer

They are most expensive of all the computers. These computers are big general-purpose computers
capable of executing more than 10,000 million instruction per second and have storage capacities of
millions of bits per chip. These computers are used to solve the multivariety mathematical problems
such as atomic nuclear and plasma physics seismology, aerodynamics etc. Super computer is typically
capable of handling hundreds of millions of floating points. Operations per second (MFLOPS). The
speed of super computers generally measured in “FLOPS” (Floating Point Operations per Second).

Super computers are used for highly calculation- intensive tasks such as weather forecasting, climate
research, molecular modelling, physical simulation, and cryptanalysis and like military are scientific
agencies are heavy users.

Supercomputers are the biggest and fastest computers. They are designed to process huge amount of
data. A supercomputer can process trillions of instructions in a second. It has thousands of
interconnected processors. Supercomputers are particularly used in scientific and engineering
applications such as weather forecasting, scientific simulations and nuclear energy research. The first
supercomputer was developed by Roger Cray in 1976.

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Basic Organization of a Digital Computer

A Computer defined as an electronic device that operates under the control of internally stored instructions that
can accept input, process data (both mathematical and logical processes), produce output and store result.
Basically, a computer transforms data into information, and to done this, there are 5 basic components/units.
Means, to accomplish the above specified task, computer have 5 functional units as depicted below through the
block diagram of computer.

Input Unit:

Input Unit contain devices with the help of which we enter data into the computer. Means with the help
of Input Unit data from outside can be supplied to the computer. Example of Input Devices are:
Keyboard, Mouse, Joystick, barcode reader, mic, etc.

Output Unit:

This unit consists of devices with the help of which we can get the information from computer. Means,
with the help of Output Unit computer results can be provided to the user.
Example of Output devices include: Printer, Monitor, speaker, etc.

3. Central Processing Unit (CPU):

Central Processing Unit is like a brain of computer. A CPU (Central Processing Unit) is the primary
component of any computer or electronic device. It’s responsible for carrying out the instructions given
to it by the user. it reads and interprets commands from software programs and uses them to control
other components within the machine. Central Processing Unit consists three basic blocks, these are:

 Arithmetic and Logical Unit (ALU):

This Unit performs Arithmetic and Logical operations on instructions. Arithmetic operations like -
addition, subtraction etc., and Logical operations like Comparison, selection etc.

 Control Unit (CU): Control Unit generates Control signals by which it controls the
operations of all parts of computer.

 Registers: Registers are high-speed storage areas that temporary stores data during processing
i.e., they may store program instruction while it is being decoded, stored data while it is being
processed by ALU, or store result of calculations.

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4. Memory Unit:

Memory Unit stores data or program either for processing or for future use. So, Memory Unit, is
any hardware capable of holding information either temporarily for processing and permanently for
future use. There are two kinds of Memory in Memory Unit, these are:

 Primary Memory:
Primary Memory hold data and application temporarily. Example of Primary storage devices
include: RAM, ROM.

 Secondary Memory (Auxiliary Memory):

Secondary Memory hold data and instruction for permanent basis. Example of Secondary Storage
devices include: Hard-Disk, Floppy-Disk, Flash Memory, etc.

Input / Output Organization

The I/O subsystem of a computer provides an efficient mode of communication between the central
system and the outside environment. It handles all the input/output operations of the computer system.

Peripheral Devices
Input or output devices that are connected to computer are called peripheral devices. These devices are
designed to read information into or out of the memory unit upon command from the CPU and are
considered to be the part of computer system. These devices are also called peripherals.

For example: Keyboards, display units and printers are common peripheral devices.

There are two types of peripherals:

1. Input peripherals: Allows user input, from the outside world to the computer.
Example: Keyboard, Mouse, Joystick, etc.

2. Output peripherals: Allows information output, from the computer to the outside world.
Example: Printer, Monitor, Speaker, projector, etc.

Input-Output Interface is used as a method which helps in transferring of information between the
internal storage devices i.e. memory and the external peripheral device.

A peripheral device is that which provide input and output for the computer, it is also called Input-
Output devices. For Example: A keyboard and mouse provide Input to the computer are called input
devices while a monitor and printer that provide output to the computer are called output devices.
Just like the external hard-drives, there is also availability of some peripheral devices which are able
to provide both input and output.

In micro-computer base system, the only purpose of peripheral devices is just to provide special
communication links for the interfacing them with the CPU.

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INPUT DEVICES:

1. 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 Internet. A computer
keyboard is an input device that allows a person to enter letters, numbers, and other symbols (these are
called characters in a keyboard) into a computer. It is one of the most used input devices for computers.

2. 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. A mouse can be used to
control the position of the cursor on the screen, but it cannot be used to enter text into the computer.

TYPES
1. Mechanical mouse
2. Optical mouse
3. Trackball mouse

1. Mechanical mouse: Houses a hard rubber ball that rolls as the mouse is moved. Sensors inside the
mouse body detect the movement and translate it into information that the computer interprets.

2. Optical mouse: Uses an LED sensor to detect tabletop movement and then sends off that information
to the computer for merry munching.

3. Trackball mouse: Like an upside-down mouse. Rather than roll the mouse around, you use your
thumb or index finger to roll a ball on top of the mouse. The whole contraption stays stationary, so it
doesn’t need a lot of room, and its cord never gets tangled.

3. 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. The function of the joystick is similar to that of a
mouse.

4. TOUCHSCREENS

A touchscreen is an electronic visual display that also incorporates an input device that responds to
touch. This allows users to select options from a screen by simply touching them. Typical Applications
• Smartphones and tablet computers, e.g. easy input of data and selection of apps/icons • Ticket /
Information kiosks, e.g. allows limited options that can be selected easily.

5. SCANNER

Scanner captures images from the source which are converted into a digital form that can be stored on
the disk. These images can be edited before they are printed. Scanner is an input device, which works

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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.

Output Devices

1. Monitor
A computer’s principal output device is a monitor, often known as a Visual Display Unit (VDU). It
displays the processed data like text, images, videos, audios, etc. It makes images by arranging
microscopic dots in a rectangular pattern, known as pixels. The sharpness of an image is determined by
the number of pixels. There are two types of monitor viewing screens:

(1) Cathode-Ray Tube (CRT)

(2) Display on a Flat Panel Monitor

2. Printer
Printers are information output devices that allow you to print data on paper. Or in other words, it is an
output device that creates a hard copy of the processed data or information. Printers are divided into
two categories:
Impact Printer

 Dot matrix printer

 Daisy wheel printer
 Line printer
 Chain printer

Non-Impact Printers
 Laser printer
 Inkjet printer

3. Projector

A projector is a device that allows users to project their output onto a large area, such as a screen or a
wall. It can be used to project the output of a computer and other devices onto a screen. It magnifies
texts, photos, and movies using light and lenses. As a result, it’s an excellent output device for giving
presentations or teaching big groups of people

4. Speakers

Speakers are connected to computers to allow sound to be output. For the working of speakers, sound
cards are required. From simple two-speaker output devices to surround-sound multi-channel sets,
speakers come in a variety of shapes and sizes. They take audio input from the computer’s sound card
and output sound waves as audio output.

Memory Organization:

The computer also has the ability to store and recall all the information and programs fed into it, which
enables it to reuse the same set of instructions over and over again when required.
The Computer Memory System consists of small bits (0 or 1).

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Some units to measure memory are;

 Bits: 1 or 0

 Nibble: 1 Nibble = 4 bits

 Bytes; 1 Byte = 8 bits

 KiloByte: 1KB = 1024 bits

 MegaBytes: 1MB=1024 KB

 GigaByte: 1 GB=1024MB

 TeraByte: 1 TB=1024GB

 PetaByte: 1 PB=1024 TB

Types of Memory System

There are two main types of computer memory:

 Primary Memory

 Secondary Memory

Types of Primary Memory

The Primary Memory is the internal memory of the computer, also known as Volatile Memory.
However, it is lost as soon as the power of the device is cut off. Some features of Primary Memory are:
 It is also known as Volatile Memory or the Main Memory.

 It is lost once the power is cut off.

 It provides the main working space for all the computer functions and processes.

Some subtypes of Primary Memory are:

 RAM

 ROM

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RAM
It stands for Random Access Memory. It is the internal memory of the CPU which stores most of the
data and the instructions for the processing of the data. Since it is the internal memory, it can only be
viewed but not modified by the user. RAM is lost once the power is cut off, and it also has limited
storage. It, however, is faster than any other storage device.

There are two different types of RAM:

 DRAM (Dynamic Random Access Memory)

 SRAM (Static Random Access Memory)

ROM
It stands for Read Only Memory. It is responsible for storing data permanently, which cannot be
changed or modified. The data stored in ROM is not rewritable as suggested by the name; it can only
be read. ROM is also a Non-Volatile Memory, which is not lost once the power is cut off.

Different Types of ROM are:

 PROM (Programmable read-only memory) – It can be programmed by the user. Once

programmed, the data and instructions in it cannot be changed.

 EPROM (Erasable Programmable read-only memory) – It can be reprogrammed. To erase data

from it, expose it to ultraviolet light. To reprogram it, erase all the previous data.

 EEPROM (Electrically erasable programmable read-only memory) – The data can be erased by
applying an electric field, with no need for ultraviolet light. We can erase only portions of the
chip.

Parameter RAM ROM

Full Form RAM stands for Random Access Memory. ROM stands for Read Only Memory.

ROM is a non-volatile memory that means it

RAM is a volatile memory. Which means it
Nature stores data permanently even when power is
stores data as long as power is on.
off.

Data The CPU of the computer can read, write, or CPU can only read data from ROM, but it can
Access alter the data on RAM. write or change.

There are two major types of RAM Three types of ROM available – PROM
available – SRAM (Static Random-Access (Programmable ROM), EPROM (Erasable
Types
Memory) and DRAM (Dynamic Random- PROM), and EEPROM (Electrically
Access Memory). EPROM).

Speed The speed of RAM is quite high. The speed of ROM is slower than RAM.

Capacity RAM memory is large and high capacity. ROM is generally small and of low capacity.

Cost RAM is costly. ROM is not so expensive.

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Secondary Memory

We have read so far, that primary memory is volatile and has limited capacity. So, it is important to
have another form of memory that has a larger storage capacity and from which data and programs are
not lost when the computer is turned off. Such a type of memory is called secondary memory.

In secondary memory, programs and data are stored. It is also called auxiliary memory. It is different
from primary memory as it is not directly accessible through the CPU and is non-volatile. Secondary
or external storage devices have a much larger storage capacity and the cost of secondary memory is
less as compared to primary memory.

A secondary memory is used to stores data permanently even if the power supply is off.
 Large Storage: Secondary memory provides large storage space so that we can store large data like
videos, images, audios, files, etc permanently.
 Portable: Some secondary devices are removable. So, we can easily store or transfer data from one
computer or device to another.

Types of Secondary memory

1. Floppy Disk: A floppy disk consists of a magnetic disc in a square plastic case. It is used to
store data and to transfer data from one device to another device.
2. Compact Disc: A Compact Disc (CD) is a commonly used secondary storage device. It contains
tracks and sectors on its surface. Its shape is circular and is made up of polycarbonate plastic.
3. DVD-ROM drive is needed to use DVD on a computer. The video files, like movies or video
recordings, etc., are generally stored on DVD.
4. Hard Disk: A hard disk is a part of a unit called a hard disk drive. It is used to storing a large
amount of data.
5. Flash Drive: A flash drive or pen drive comes in various storage capacities, such as 1 GB, 2 GB,
4 GB, 8 GB, 16 GB, 32 GB, 64 GB, up to 1 TB. A flash drive is used to transfer and store data.
6. SD Card: It is known as a Secure Digital Card. It is generally used in portable devices like mobile
phones, cameras, etc.,

Characteristics of Memory in Computer

1. Location:
It deals with the location of the memory device in the computer system. There are three possible
locations:

 CPU : This is often in the form of CPU registers and small amount of cache
 Internal or main: This is the main memory like RAM or ROM. The CPU can directly access
the main memory.
 External or secondary: It comprises of secondary storage devices like hard disks, magnetic
tapes. The CPU doesn’t access these devices directly. It uses device controllers to access
secondary storage devices.

2. Capacity:
The capacity of any memory device is expressed in terms of: i)word size ii)Number of words
 Word size: Words are expressed in bytes (8 bits). A word can however mean any number of
bytes. Commonly used word sizes are 1 byte (8 bits), 2bytes (16 bits) and 4 bytes (32 bits).

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3. Unit of Transfer:
It is the maximum number of bits that can be read or written into the memory at a time. In case of
main memory, it is mostly equal to word size. In case of external memory, unit of transfer is not
limited to the word size; it is often larger and is referred to as blocks.
4. Access Methods:
It is a fundamental characteristic of memory devices. It is the sequence or order in which memory can
be accessed.
5. Performance: The performance of the memory system is determined using three parameters
 Access Time: In random access memories, it is the time taken by memory to complete the
read/write operation from the instant that an address is sent to the memory.
6. Physical type: Memory devices can be either semiconductor memory (like RAM) or magnetic
surface memory (like Hard disks).
7. Physical Characteristics:

 Volatile/Non- Volatile: If a memory device continues hold data even if power is turned off.
The memory device is non-volatile else it is volatile.

Software:
The software is basically a set of instructions or commands that tells a computer what to do. Or in
other words, the software is a computer program that provides a set of instructions to execute a user’s
commands and tell the computer what to do. For example like MS-Word, MSExcel, PowerPoint, etc.
The chart below describes the types of software:

Types of software:

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System Software:

System software is software that directly operates the computer hardware and provides the basic
functionality to the users as well as to the other software to operate smoothly. Or in other words, system
software basically controls a computer’s internal functioning and also controls hardware devices such
as monitors, printers, and storage devices, etc. It is like an interface between hardware and user
applications, it helps them to communicate with each other because hardware understands machine
language (i.e. 1 or 0) whereas user applications are work in human-readable languages like English,
Hindi, German, etc. so system software converts the human-readable language into machine language
and vice versa.

Features of system software:

1. System Software is closer to the computer system.

2. System Software is written in a low-level language in general.
3. System software is difficult to design and understand.
4. System software is fast in speed(working speed).
5. System software is less interactive for the users in comparison to application software.

Types of system software: It has subtypes which are:

1. Operating System: It is the main program of a computer system. When the computer system ON it
is the first software that loads into the computer’s memory. Basically, it manages all the resources such
as memory, CPU, printer, hard disk, etc., and provides an interface to the user, which helps the user to
interact with the computer system. It also provides various services to other computer software.
Examples of operating systems are Linux, Apple macOS, Microsoft Windows, etc.

2. Language Processor: As we know that system software converts the human readable language into
a machine language and vice versa. So, the conversion is done by the language processor. It converts
programs written in high level programming languages like Java, C, C++, Python, etc (known as source
code), into sets of instructions that are easily readable by machines (known as object code or machine
code).

3. Device Driver: A device driver is a program or software that controls a device and helps that device
to perform its functions. Every device like a printer, mouse, modem, etc. needs a driver to connect with
the computer system eternally. So, when you connect a new device with your computer system, first
you need to install the driver of that device so that your operating system knows how to control or
manage that device.

Application Software

Software that performs special functions or provides functions that are much more than the basic
operation of the computer is known as application software. Or in other words, application software is
designed to perform a specific task for end-users. It is a product or a program that is designed only to
fulfil end-users requirements. Example: MS Office(word processors, spreadsheets, PowerPoint)
database management, inventory, gaming software, Adobe, Photoshop, etc.

Features of application software: Let us discuss some of the features of Application Software:
1. An important feature of application software is it performs more specialized tasks like word
processing, spreadsheets, email, etc.

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2. Mostly, the size of the software is big, so it requires more storage space.
3. Application software is more interactive for the users, so it is easy to use and design.
4. The application software is easy to design and understand.
5. Application software is written in a high-level language in general.

Types of application software: There are different types of application software and those are:

1. General Purpose Software: This type of application software is used for a variety of tasks and it is
not limited to performing a specific task only. For example, MS-Word, MS-Excel, PowerPoint, etc.

2. Customized Software: This type of application software is used or designed to perform specific tasks
or functions or designed for specific organizations. For example, railway reservation system, airline
reservation system, invoice management system, etc.

Utility software
Utility software is part of the system software and performs specific tasks to keep the computer running.
Utility software is always running in the background. Examples of utility software are security and
optimisation programs.
Security programs include anti-virus software that scans and removes viruses. Most computers will
include some sort of anti-virus software, but you can add your own. These tools are typically installed
as part of the operating system.

Computer Languages: A computer cannot understand human languages directly. So, we need a
language to communicate with a computer. We developed several languages as a method of computer
communications. Simply, the languages which are used to communicate with a computer are called
computer languages.

Types of Computer Languages

1. Low Level Language:

A Low-level computer language includes only 1’s and 0’s. This language was used in first and
second generation computers. A Low level language is very easily understood by a computer
but hard to understand for Humans.
Low level languages are designed to interact with computer hardware, which are categorized
into two types: Machine level language and Assembly level language.

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2. Machine Language: As discussed above, Machine level language is a type of Low level language.
Machine language is considered to be the oldest computer language. Machine language is
developed by only using binary numbers i.e., 0 and 1. So, the instructions or the statements in
this language use a sequence of 0’s and 1’s.
Example of a statement in Machine code: 101010001011

3. Assembly Language: Assembly level language in computer programming has evolved with the
advancements in the machine language. Assembly language uses symbols, which are popularly
known as mnemonics in computer terminology to write the instructions. So, comparatively
writing a program in Assembly language is more understandable to the Human than Machine
Language.
Example of mnemonics in Assembly code: LOAD r2, a; CLR, MOV, MOVL, PUSH.

The Assembly language code will be converted into a Machine language code with the help of
an Assembler so that the computer can understand the binary converted Assembly Language.

4. High Level Language: High Level computer languages are the advanced development
languages in the evolution of computer languages. These languages are designed to make the
programming easier and less error-free.

High level language uses words and commands along with symbols and numbers.

The keywords used in High level languages are similar to English words and can be easily
understood by Humans when compared to a Low level language.
Types of programming languages in High level languages are:

 C

 C++

 Java

 Java Script

 Python

 C#

 PHP
Example of a statement in High level language: Printf (“Hi”);

Difference Between High-Level and Low-Level Computer languages

S.
Low Level Computer Language High Level Computer Language
No

Low level languages are hard to understand by High level languages are simple to
1. humans as they use binary numbers and easy to understand by humans as they use
understand by the computer. English statements.

High level languages are human

2. Low level languages are programmer-friendly
friendly.

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3. These are complex to maintain. These are simple to maintain.

Debugging process is hard. It is easy to debug in High level

4.
languages.

The programs in a high level language

The programs in low level language are not
5. are portable, so we can use them on
portable from one computer to another.
any computer.

Usage of low level language is less in today’s We use high level language in today’s
6.
technologies. technologies.

Language Translators:

A translator is a computer program that can translate a program written in one programming language
into another. Language translators are also called language processors.
Code written in any high-level programming language is called “source code”. When you change the
source code into machine code, it is called “object code”. A translator turns the source code into object
code, which the computer can understand and run.
There are three types of language translators:

 Assemblers
 Compilers
 Interpreters

Assemblers

Assemblers translate a program written in assembly language into machine language. Assembly
language is a low-level programming language.

low-level programming languages are more difficult to understand. You have to study assembly
code carefully to understand it.

Compiler

A compiler that translates code written in a high-level language into a low-level language, machine
code. The most common reason for translating source code is to create an executable program
(converting from high-level language into machine language). A compiler makes machine code that
runs on a processor.

Interpreters

An interpreter is like a compiler, it converts high level language into low level language line by line.
but it takes the code and runs it right away, so it is faster than a compiler. They are used as debugging
tools because interpreters can only run one piece of code at a time. Translating all the code into machine
language at once is done by compilers.

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