Secondary Memory

You know that processor memory, also known as primary memory, is expensive as well as limited. The faster primary memory are also volatile. If we need to store large amount of data or programs permanently, we need a cheaper and permanent memory. Such memory is called secondary memory. Here we will discuss secondary memory devices that can be used to store large amount of data, audio, video and multimedia files.

Characteristics of Secondary Memory

These are some characteristics of secondary memory, which distinguish it from primary memory −

  • It is non-volatile, i.e. it retains data when power is switched off
  • It is large capacities to the tune of terabytes
  • It is cheaper as compared to primary memory

Depending on whether secondary memory device is part of CPU or not, there are two types of secondary memory – fixed and removable.

Secondary Memory
Secondary Memory

Let us look at some of the secondary memory devices available.

Hard Disk Drive

Hard disk drive is made up of a series of circular disks called plattersarranged one over the other almost ½ inches apart around a spindle. Disks are made of non-magnetic material like aluminum alloy and coated with 10-20 nm of magnetic material.

Hard Disk Drive
Hard Disk Drive

Standard diameter of these disks is 14 inches and they rotate with speeds varying from 4200 rpm (rotations per minute) for personal computers to 15000 rpm for servers. Data is stored by magnetizing or demagnetizing the magnetic coating. A magnetic reader arm is used to read data from and write data to the disks. A typical modern HDD has capacity in terabytes (TB).

CD Drive

CD stands for Compact Disk. CDs are circular disks that use optical rays, usually lasers, to read and write data. They are very cheap as you can get 700 MB of storage space for less than a dollar. CDs are inserted in CD drives built into CPU cabinet. They are portable as you can eject the drive, remove the CD and carry it with you. There are three types of CDs −

  • CD-ROM (Compact Disk – Read Only Memory) − The data on these CDs are recorded by the manufacturer. Proprietary Software, audio or video are released on CD-ROMs.

  • CD-R (Compact Disk – Recordable) − Data can be written by the user once on the CD-R. It cannot be deleted or modified later.

  • CD-RW (Compact Disk – Rewritable) − Data can be written and deleted on these optical disks again and again.

DVD Drive

DVD stands for Digital Video Display. DVD are optical devices that can store 15 times the data held by CDs. They are usually used to store rich multimedia files that need high storage capacity. DVDs also come in three varieties – read only, recordable and rewritable.

DVD Drive
DVD Drive

Pen Drive

Pen drive is a portable memory device that uses solid state memory rather than magnetic fields or lasers to record data. It uses a technology similar to RAM, except that it is nonvolatile. It is also called USB drive, key drive or flash memory.

Pen Drive
Pen Drive

Blu Ray Disk

Blu Ray Disk (BD) is an optical storage media used to store high definition (HD) video and other multimedia filed. BD uses shorter wavelength laser as compared to CD/DVD. This enables writing arm to focus more tightly on the disk and hence pack in more data. BDs can store up to 128 GB data.

Fundamental Concept

A computer is basically a programmable machine capable to perform arithmetic and logical operations automatically and sequentially. It is also known as a data processor, as it can store, process, and retrieve data as per the wish of the user.

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Computer
Computer 

Data processing involves the following three activities −

  • Input of data
  • Manipulation/processing of data
  • Giving output (i.e. management of output result)
  • In computer system, data is arranged orderly and systematically.

The term “computer” is derived from a Latin term “compute,” which means ‘to calculate.’ Initially, the computer system had been designed to calculate; it was intended to be a computing device. However, over a period of time, this device technically advanced; at present, it can perform a wide range of desirable works apart from data processing.

Major Functions of Computer System

Following are the core functions of a computer system −

  • A computer accepts the command and/or data as input given by the user.

  • A computer follows the instructions and stores the data given by the user.

  • A computer processes the data as per the instructions given by the user.

  • A computer gives the desirable results in the form of output.

Salient Features of Computer System

Following are the salient features of a Computer System −

  • Automation − The operating system of a computer system is automatic, as no human intervention is required; simply you need to give the command and then it will do the work automatically.

  • Speed − Depending upon the power of the computer, it can perform, it can take Millions of instructions per second.

  • Storage − A computer system can store enormous quantity of data in different format. The storage capacity of a computer system is normally expressed in terms of Kilobytes (KB), Megabytes (MB), Gigabytes (GB), or Terabytes (TB).

  • Accuracy − The accuracy of a computer system is very high.

  • Versatility − A computer system is capable of performing a wide range of tasks.

  • Diligence − A computer neither get tired nor lose concentration.

  • Reliability − As a computer system always gives accurate result; therefore, its reliability is very high.

  • Vast memory − A computer system can have a wide range of memory which can recall the desired data at any point of time.

Evolution of Computer System

The present Computer System has evolved after centuries of efforts from different intellectuals who contributed their works during different periods of time.

Abacus is (most likely) considered as the earlier counting device.

Let us now read about the innovators who contributed immensely in the development of a computer system.

John Napier

Napier was a Scottish mathematician who invented logarithms.

Further, Napier also invented a computing device, which consisted of sticks with numbers imprinted on them. Napier named sticks ‘bones,’ as they were made up of bones.

Blaise Pascal

Pascal was a French mathematician who invented a machine based on gear wheels, which helped greatly in calculation.

Charles Babbage

Babbage was an English Polymath, Mathematician, Mechanical Engineer, Philosopher, and Inventor. In 1822, he developed a machine capable to calculate the successive difference of expression and prepared a table which helped him in his calculations.

Lady Ada Lovelace

Lovelace was an English mathematician, who researched on Babbage’s work. She has given the concept that ‘computers can be programmed’. Her work helped a great deal in the advancement of computer system.

John Atanstoff

With the assistance of Berry, John Atanstoff developed the Atanstoff Berry Computer (more popular as ABC) in 1937. It marked the beginning of the development of electronic digital computer.

John Mauchly and Eckart

In 1947, John Mauchly and Eckart developed the first large scale Electronic Digital Computer. It was called the Electronic Numerical Integrator and Calculator (ENIAC).

Maurice V. Wilkes

In 1949, Wilkes (at Cambridge University) designed Electronic Delay Storage Automatic Calculator (EDSAC). It was the first computer that started its operating system on the stored program concept.

Computer’s Input/Output Ports

A connection point that acts as interface between the computer and external devices like mouse, printer, modem, etc. is called port. Ports are of two types 

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  • Internal port − It connects the motherboard to internal devices like hard disk drive, CD drive, internal modem, etc.

  • External port − It connects the motherboard to external devices like modem, mouse, printer, flash drives, etc.

Input Output Ports
Input Output Ports

Let us look at some of the most commonly used ports.

Serial Port

Serial ports transmit data sequentially one bit at a time. So they need only one wire to transmit 8 bits. However it also makes them slower. Serial ports are usually 9-pin or 25-pin male connectors. They are also known as COM (communication) ports or RS323C ports.

Serial Ports
Serial Ports

Parallel Port

Parallel ports can send or receive 8 bits or 1 byte at a time. Parallel ports come in form of 25-pin female pins and are used to connect printer, scanner, external hard disk drive, etc.

Parallel Ports
Parallel Ports

USB Port

USB stands for Universal Serial Bus. It is the industry standard for short distance digital data connection. USB port is a standardized port to connect a variety of devices like printer, camera, keyboard, speaker, etc.

USB Port
USB Port

PS-2 Port

PS/2 stands for Personal System/2. It is a female 6-pin port standard that connects to the male mini-DIN cable. PS/2 was introduced by IBM to connect mouse and keyboard to personal computers. This port is now mostly obsolete, though some systems compatible with IBM may have this port.

Infrared Port

Infrared port is a port that enables wireless exchange of data within a radius of 10m. Two devices that have infrared ports are placed facing each other so that beams of infrared lights can be used to share data.

Bluetooth Port

Bluetooth is a telecommunication specification that facilitates wireless connection between phones, computers and other digital devices over short range wireless connection. Bluetooth port enables synchronization between Bluetooth-enabled devices. There are two types of Bluetooth ports −

  • Incoming − It is used to receive connection from Bluetooth devices.

  • Outgoing − It is used to request connection to other Bluetooth devices.

FireWire Port

FireWire is Apple Computer’s interface standard for enabling high speed communication using serial bus. It is also called IEEE 1394 and used mostly for audio and video devices like digital camcorders.

Role of Computer in Today’s World

In today’s world, for almost every activity whether personal (for example, operating personal savings bank account) or business-related (for example, selling any product or services); in some or the other way, we rely on the computer system.

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Due to the growing dependency on computers, every small and big organizations and other business companies have started offering computer-based service. Furthermore, the advancement of communications, electronic service networks, and multimedia have opened a new door for corporates by providing an effective way of business processing, payment transfer, and service delivery.

Advantages of Computers in Business

Following are the major advantages of introducing computer system in business −

Independency

As computers help in making the business automated, the businesses are becoming more and more independent. No more, there is the need to put man-power for every work, as with the help of computer most of the works can be automated. Starting from ticket booking to a luxury car manufacturing, everything is automated.

Independency
Independency

Cost Cutting

A number of business are based online in recent times; therefore, there is no need to open business branch in every city, rather having one centralized inventory can make the business easier. There is no need to employ many man-power.

Marketing

With the use of computer system with Internet facility, it is very simple to make a business global in a given period of time. Website, email, social media websites, online advertisements, etc. are the important tools of online marketing.

Marketing
Marketing

Huge Transaction Capacity

A number of tasks are being done by computer including ticket booking to money transactions; this increases the transaction capacity.

Huge Storage Capacity

Normally, most of the businesses need to store and maintain huge data and other records; manually, it is very difficult to maintain, but the use of computer not only increases the storage capacity, but also facilitates the processing and retrieval of data anytime.

Improvement of Productivity & Efficiency

As most of the tasks in almost every industry has become automated, it has now become much easier to manufacture a huge bulk of products in very less time. Through computer technology, services also became faster and easier.

High Accuracy

There is hardly any scope of errors in an automated system; however, if any error occurs, it is largely a human error.

Ease of Data Sharing

Data sharing has now become very simple just the way it is simple to link one computer system to another.

Competition

The applicability of computer technology has increased competition; now, the customers can avail support 24×7.

Enhanced the Security System

Computer also helps keep the data of businesses secure. However, this security can face threats too. For instance, if someone hacks the system or there is a virus attack, it can have the potential to damage all the data that is secured.

Computer System

A computer system is an integrated form of different components that work together to give a desirable result. It has different component and each works for a specific purpose; however, they generate a common result as required by the user.

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Computer System
Computer System

Components of Computer System

Let us now understand the following basic components of a computer system.

  • Hardware
  • Software
  • Humanware
  • Firmware
  • Bridgeware

Hardware

The physical components collectively form the hardware of a computer system. Hardware comprises of the equipment that helps in the working system of the computer.

Following are the different types of hardware components (which have specific functions) −

  • Monitor − It displays (visual) the result.

  • CPU − It is the Central Processing Unit that controls the computer’s functions and transmits data.

  • Motherboard − It is mainly accountable to establish communication between components and transmission of information.

  • RAM − It is the Random Access Memory and responsible for the storage of programs that are currently running and also stores data temporarily.

  • Hard Disk Drive − It is a permanent memory storage device.

  • Floppy Disk Drive − It is hardly being used in recent times.

  • Optical disks − It is a device that also store data. For example, CD, DVD, etc.

Input & Output Device

The following table categorically lists down the input and output device −

Input Device Output Device Input Device Output Device
Mouse Monitor Microphone Speaker
Keyboard Printer Camera Earphone
Scanner Projector Trackball Monitor
Touchpad Plotter Joystick Monitor

Software

The hardware components can only function when software components are added to the computer system. Software is a program that performs different commands given by a user.

Software is an intangible part of hardware and controls the sequence of operations.

Types of Software

Depending on the basic features and functionality, software can be categorized as −

  • Operating Systems (OS)
  • Application Software (AS)
  • E-accessibility Software

Let us now discuss the software components in brief.

Operating System

This software helps to load the basic program automatically as soon as the computer is started. Following are the major types of operating system −

Operating Software Examples
Microsoft Windows XP, Vista, etc.
Mac OS X Panther, Cheetah, Snow leopard, etc.
Linux Debian, Ubuntu, Fedora, Knoppix, etc.

Application Software

The software, which can be used on an installed operating system, is known as application software. Following are the significant examples of application software −

Application Software Examples
Office programs Microsoft Office, OpenOffice, LibreOffice, etc.
Web browser Internet Explorer, Mozilla Firefox, Google Chrome, Opera, Safari, etc.
Antivirus Program Norton, McAfee, Quick Heal, Avira, Kaspersky, etc.

E-accessibility Software

The E-accessibility software components additional facilities to users such as −

  • Voice recognition software
  • Screen reader
  • Magnifying tool
  • On-screen keyboard
  • Video games
  • Learning software, etc.

Computer Programming Languages

The computer system is simply a machine and hence it cannot perform any work; therefore, in order to make it functional different languages are developed, which are known as programming languages or simply computer languages.

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Over the last two decades, dozens of computer languages have been developed. Each of these languages comes with its own set of vocabulary and rules, better known as syntax. Furthermore, while writing the computer language, syntax has to be followed literally, as even a small mistake will result in an error and not generate the required output.

Following are the major categories of Programming Languages −

  • Machine Language
  • Assembly Language
  • High Level Language
  • System Language
  • Scripting Language

Let us discuss the programming languages in brief.

Machine Language or Code

This is the language that is written for the computer hardware. Such language is effected directly by the central processing unit (CPU) of a computer system.

Assembly Language

It is a language of an encoding of machine code that makes simpler and readable.

High Level Language

The high level language is simple and easy to understand and it is similar to English language. For example, COBOL, FORTRAN, BASIC, C, C+, Python, etc.

High-level languages are very important, as they help in developing complex software and they have the following advantages −

  • Unlike assembly language or machine language, users do not need to learn the high-level language in order to work with it.

  • High-level languages are similar to natural languages, therefore, easy to learn and understand.

  • High-level language is designed in such a way that it detects the errors immediately.

  • High-level language is easy to maintain and it can be easily modified.

  • High-level language makes development faster.

  • High-level language is comparatively cheaper to develop.

  • High-level language is easier to document.

Although a high-level language has many benefits, yet it also has a drawback. It has poor control on machine/hardware.

The following table lists down the frequently used languages −

Languages
Languages

Operating System

An operating system is the fundamental basis of all other application programs. Operating system is an intermediary between the users and the hardware.

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Operating system controls and coordinates the use of hardware among application programs. The major services of an operating system are −

  • Memory management
  • Disk access
  • Creating user interface
  • Managing the different programs operating parallel
  • Likewise, it controls and manage the hardware’s working
Operating System
Operating System

Applications of Operating System

Following are the major applications of an operating system −

  • An operating system is accountable for the formation and deletion of files and directories.

  • An operating system manages the process of deletion, suspension, resumption, and synchronization.

  • An operating system manages memory space by allocation and de-allocation.

  • An operating system stores, organizes, and names and protects the existing files.

  • Further, an operating system manages all the components and devices of the computers system including modems, printers, plotters, etc.

  • In case, if any device fails, the operating system detects and notify.

  • An operating system protects from destruction as well as from unauthorized use.

  • An operating system facilitates the interface to user and hardware.

Types of Operating System

Following are the major types of operating system −

  • Disk Operating System (DOS)
  • Windows Operating System
  • Unix Operating System

Let us now discuss each operating system in detail.

Disk Operating System

MS-DOS is one of the oldest and widely used operating system. DOS is a set of computer programs, the major functions of which are file management, allocation of system resources, providing essential features to control hardware devices.

DOS commands can be typed in either upper case or lower case.

Features of DOS

Following are the significant features of DOS −

  • It is a single user system.
  • It controls program.
  • It is machine independence.
  • It manages (computer) files.
  • It manages input and output system.
  • It manages (computer) memory.
  • It provides command processing facilities.
  • It operates with Assembler.

Types of DOS Commands

Following are the major types of DOS Command −

  • Internal Commands − Commands such as DEL, COPY, TYPE, etc. are the internal commands that remain stored in computer memory.

  • External Commands − Commands like FORMAT, DISKCOPY, etc. are the external commands and remain stored on the disk.

Windows Operating System

The operating system window is the extension of the disk operating system.

It is the most popular and simplest operating system; it can be used by any person who can read and understand basic English, as it does not require any special training.

However, the Windows Operating System requires DOS to run the various application programs initially. Because of this reason, DOS should be installed into the memory and then window can be executed.

Elements of Windows OS

Following are the significant element of Windows Operating System (WOS) −

  • Graphical User Interface
  • Icons (pictures, documents, application, program icons, etc.)
  • Taskbar
  • Start button
  • Windows explorer
  • Mouse button
  • Hardware compatibility
  • Software compatibility
  • Help, etc.

Versions of Windows Operating System

Following are the different versions of Windows Operating System −

Version Year Version Year
Window 1.01 1985 Windows XP Professional x64 2005
Windows NT 3.1 1993 Windows Vista 2007
Windows 95 1995 Windows 7 2009
Windows 98 1998 Windows 8 2012
Windows 2000 2000 Windows 10 2015
Windows ME 2000 Windows Server 2016 2016
Windows XP 2001    

Unix Operating System

The Unix Operating System is the earliest operating system developed in 1970s. Let us consider the following points relating to the Unix Operating System −

  • It is an operating system that has multitasking features.

  • It has multiuser computer operating systems.

  • It runs practically on every sort of hardware and provides stimulus to the open source movement.

  • It has comparative complex functionality and hence an untrained user cannot use it; only the one who has taken training can use this system.

  • Another drawback of this system is, it does not give notice or warn about the consequences of a user’s action (whether user’s action is right or wrong).

Internet

Internet is a system that interconnects the different computer systems across the world. It uses the Internet protocol suite to link devices located in different corners of the world.

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The Internet system carries an extensive range of information resources and services including World Wide Web (WWW), telephony, electronic mail, etc. It uses standard internet protocols, such as TCP/IP and HTTP, etc.

Internet
Internet

An internal web comprises of all Hypertext Transfer Protocol (HTTP) nodes on a private network; for example, an organization’s LAN or WAN.

Features of Internet

Let us now discuss the features of Internet. The features are described below −

Accessibility

An Internet is a global service and accessible to all. Today, people located in a remote part of an island or interior of Africa can also use Internet.

Easy to Use

The software, which is used to access the Internet (web browser), is designed very simple; therefore, it can be easily learned and used. It is easy to develop.

Interaction with Other Media

Internet service has a high degree of interaction with other media. For example, News and other magazine, publishing houses have extended their business with the help of Internet services.

Low Cost

The development and maintenance cost of Internet service are comparatively low.

Extension of Existing IT Technology

This facilitates the sharing of IT technology by multiple users in organizations and even facilitates other trading partners to use.

Flexibility of Communication

Communication through Internet is flexible enough. It facilitates communication through text, voice, and video too. These services can be availed at both organizational and individual levels.

Security

Last but not the least, Internet facility has to a certain extent helped the security system both at the individual and national level with components such as CCTV camera, etc.

Security
Security

Internet Software

Internet Software comprises of all the tools needed for networking through computer. Following are a few important components of the Internet Software −

  • Transmission Control Protocol/ Internet Protocol (TCP/IP)
  • Dialer Software
  • Interment Browser

Internet Applications

Internet applications are server-based applications. Following are a few Internet Applications −

  • World Wide Web (WWW)
  • Electronic mail (e-mail)
  • File Transfer Protocol (FTP)
  • Telnet (i.e., log-in to the computer located remotely)
  • Internet Relay Chat (IRC) (Real time video chatting)

Types of Computer

All the computers that are developed are not alike rather they have different designs and features. Some computers have very high capacity as well as working speed; however, some are slow. Depending upon the requirements, computers are being developed.

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Types of Computer

Depending upon the internal structure and subsequent features and applicability, computer system is categorized as follows −

Mainframe Computer

It is high capacity and costly computer. It is largely used by big organizations where many people can use it simultaneously.

Super Computer

This category of computer is the fastest and also very expensive. A typical supercomputer can solve up to ten trillion individual calculations per second.

Workstation Computer

The computer of this category is a high-end and expensive one. It is exclusively made for complex work purpose.

Workstation Computer
Workstation Computer

Personal Computer (PC)

It is a low capacity computer developed for single users.

Apple Macintosh (Mac)

It is a sort of personal computer manufactured by Apple company.

Laptop computer (notebook)

It is a handy computer that can be easily carried anywhere.

Tablet and Smartphone
Tablet and Smartphone

Tablet and Smartphone

Modern technology has advanced further. It has helped develop computers that are pocket-friendly. Tablets and smartphones are the best examples of such computer.

Computer Networking Terminology

In this chapter, we will discuss the major terminologies used in computer networking 

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WAN

It stands for Wide Area Network and covers a wide area such as a city.

LAN

It stands for Local Area Network and covers a small area such as a small office or home. It physically connects all the computers located in the premises.

Internet

It is a computer network system that connects the computers of the world. It is normally connecting through WAN and LAN.

Intranet

It is a close room computer network system, as it covers a small area and only authorized people can access it.

Extranet

It is also a sort of Internet the access to which is granted only to a few.

World Wide Web (WWW)

It is the service that is used on Internet to view and search contents (in the form of web-pages).

Instant messaging (IM)

It is an online facility that facilitates us to chat or talk. Such service is provided by Skype, Google Talk, Windows Live Messenger, Yahoo Messenger, etc.

Voice over Internet Protocol (VoIP)

It is a Protocol, which is used especially for voice transfer over IP network. Likewise, it facilitates users to make phone-calls by using internet.

Really Simple Syndication (RSS)

It is a technique, which is used for the dissemination of information, articles, etc. Users normally subscribe to the RSS channel in order to receive news. After subscription, users do not need to visit the respective website rather they receive emails regarding the same.

Web log

It is a sort of online inventory (normally on a specialized topics) that consists of a series of entries. These entries are arranged in opposite chronological order. The person who maintains the weblog regularly update it with a new information.

Podcast

It is a digital file that normally contains audio or video record and is available on the Internet as well.

Social networking websites

It refers to the websites that facilitate users with a common platform where they can share their message (in text, audio, or even video form), images, videos, etc. For example, Facebook, Google+, Twitter, LinkedIn, MySpace, etc.

Social Networking Websites
Social Networking Websites

Chat Rooms

It is a dedicated area on the Internet that facilitates users to communicate.

Public Switched Telephone Network (PSTN)

It is a technical expression for public telephone system.

Integrated Services Digital Network (ISDN)

It is a set of communication standards that transmits voice, video, data, and other network services simultaneously.

Asymmetric Digital Subscriber Line (ADSL)

It is a sort of digital subscriber line (DSL) technology that facilitates faster data transmission.

Download

It is a process that saves data from Internet onto a personal computer.

Upload

It is a process that transfers the saved data from a personal computer to Internet server.

Dial-up

It is a technique in which a phone line is used in order to connect to the Internet.

Broadband

It is a wide bandwidth data transmission that transports multiple signals and traffic types swiftly.