Secondary Memory

All secondary storage devices which are capable of storing high volume data is referred to secondary memory. It's slower than primary memory. However, it can save a substantial amount of data, in the range of gigabytes to terabytes. This memory is also called backup storage or mass storage media.

Types of Secondary memory

Mass storage devices:

The magnetic disk provides cheap storage and is used for both small and large computer systems.

Two types of magnetic disks are:

• Floppy disks
• Hard disks

Flash/SSD

Solid State Drive provides a persistent flash memory. It's very fast compared to Hard Drives. Frequently found in Mobile phones, its rapidly being adopted in PC/Laptop/Mac.

Optical drives:

This secondary storage device is from which data is read and written with the help of lasers. Optical disks can hold data up to 185TB.

Examples

• CD
• DVD
• Blue Ray

USB drives:

It is one of the most popular types of secondary storage device available in the market. USB drives are removable, rewritable and are physically very small. The capacity of USB drives is also increasing significantly as today 1TB pen drive is also available in the market.

Magnetic tape:

It is a serial access storage device which allows us to store a very high volume of data. Usually used for backups.

Characteristic Secondary Memory

• These are magnetic and optical memories
• Secondary memory is known as a backup memory
• It is a non-volatile type of memory
• Data is stored permanently even when the power of the computer is switched off
• It helps store data in a computer
• The machine can run without secondary memory
• Slower than primary memory

Primary Memory

Primary memory is computer memory that is accessed directly by the CPU.RAM, or random access memory, consists of one or more memory modules that temporarily store data while a computer is running.

Primary memory is also known as Main memory or Internal memory.

RAM is volatile memory, meaning it is erased when the power is turned off.

Characteristic of Primary Memory

• The computer can't run without primary memory
• It is known as the main memory.
• You can lose data in case power is switched off
• It is also known as volatile memory
• It is a working memory of the computer.
• Primary memory is faster compares to secondary memory.

Two Types of Primary Memory are:

• RAM
• ROM

RAM

The full form of RAM is Random Access Memory. The information stored in this type of memory is lost when the power supply to the PC or laptop is switched off. The information stored in RAM can be checked with the help of BIOS. It is generally known as the main memory or temporary memory or cache memory or volatile memory of the computer system.

Two main types of RAM are:

• Static RAM
• Dynamic RAM

Static RAM

Static RAM is the full form of SRAM. In this type of RAM, data is stored using the state of a six transistor memory cell. Static RAM is mostly used as a cache memory for the processor (CPU).

Dynamic RAM

DRAM stands for Dynamic Random Access Memory. It is a type of RAM which allows you to stores each bit of data in a separate capacitor within a specific integrated circuit. Dynamic RAM is a standard computer memory of the many modern desktop computers.

This type of RAM is a volatile memory that needs to be refreshed with voltage regularly. Else it loses the information stored on it.

Uses of RAM

Here, are important uses of RAM:

• RAM is utilized in the computer as a scratchpad, buffer, and main memory.
• It offers a fast operating speed.
• It is also popular for its compatibility
• It offers low power dissipation

ROM

ROM (read only memory) is a flash memory chip that contains a small amount of non-volatile memory. Non-volatile means that its contents cannot be changed and it retains its memory after the computer is turned off.

Types of ROM

PROM: Programmable ROM, or PROM, is essentially a blank version of ROM that you can purchase and program once with the help of a special tool called a programmer. A blank PROM chip allows current to run through all possible pathways; the programmer chooses a pathway for the current by sending a high voltage through the unwanted fuses to “burn” them out. Static electricity can create the same effect by accident, so PROMs are more vulnerable to damage than conventional ROMs.

EPROM: Erasable Programmable ROM chips allow you to write and rewrite them many times. These chips feature a quartz window through which a specialized EPROM programmer emits a specific frequency of ultraviolet light. This light burns out all the tiny charges in the EPROM to reopen its circuits. This exposure effectively renders the chip blank again, after which you can reprogram it according to the same process as a PROM. EPROM chips will eventually wear out, but they frequently have lifetimes of over 1000 erasures.

EEPROM: To modify an Electrically Erasable Programmable ROM chip, apply localized electrical fields to erase and rewrite the data. EEPROMs have several advantages over other types of ROM. Unlike the earlier forms, you can rewrite EEPROM without dedicated equipment, without removing it from the hardware, and in specifically designated increments. You don’t have to erase and rewrite everything to make a single edit.

Cache Memory

Cache memory is an extremely fast memory type that acts as a buffer between RAM and the CPU. It holds frequently requested data and instructions so that they are immediately available to the CPU when needed. Cache memory is used to reduce the average time to access data from the Main memory.

Register

A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only.

 

 

 

 

 

 

Software Concepts

A Computer is an electronic device that can perform various operations of computation at a greater speed than what an ordinary machine or human mind can do. It is driven by many entities including the physical and tangible components that we can touch or feel, called the Hardware and programs and commands that drive the hardware, called the Software.
The Software refers to the set of instructions fed in form of programs to govern the computer system and process the hardware components. For example:

• The antivirus that we use to protect our computer system is a type of Software.
• The media players that we use to play multimedia files such as movies, music etc. are Software.
• The Microsoft Office we use to edit the documents is a Software.

Depending on its use and area of implementation, Softwares can be divided into 3 major types:

1. System Software
2. Application Software
3. Utility Software

System Software

These are the software that directly allows the user to interact with the hardware components of a computer system. As the humans and machines follow different languages, there has to be an interface that will allow the users to interact with the core system, this interface is provided by the software. The system software can be called the main or the alpha software of a computer system as it handles the major portion of running a hardware. This System Software can be further divided into four major types:

1. The Operating System – It is the main program that governs and maintains the inter-cooperation of the components of a computer system. For eg., Microsoft Windows, Linux, Mac OS etc.
2. The Language Processor – The hardware components present in the computer system does not understand human language. There are three types of languages involved in the world of human-machine interaction:
   
    
   
   
   • Machine-Level Language: The machines only understand the digital signals or the binary codes or the binary language which consist of strings of 0’s and 1’s. These are totally machine dependent language.
   • Assembly-Level Language: These are the Low-Level Language(LLL), that forms a correspondence between machine level instruction and general assembly level statements. Assembly language uses a mnemonics to represent each low-level machine instruction or operation-code also called the op-codes. For eg., ADD instruction is used to add two entities, the HALT instruction is used to stop a process etc. It is a machine dependent language and varies from processor to processor.
   • High-Level Language: These are the simple English statements, that humans use to program and code as it is easy to read and understand to the human world. For eg., Java, C, C++, Python etc.

   The machine level language is very complex to understand and code, therefore the users prefer the High-Level Language or the HLL for coding. These codes need to be converted into the machine language so that the computer can easily understand and work accordingly. This operation is performed by the Language Processor which is made up of further three components:

   • Assembler: This language processor is used to convert the assembly language into machine level language.
   • Compiler: This language processor is used to convert High-Level Language into machine level language in one go, thus execution time is fast. The error detection is difficult in a compiler. Programming Languages like C, C++ and Scala use compiler.
   • Interpreter: This language processor is also used to convert High-Level Language into machine level language line-by-line, thus execution time is slow. Error-detection is easier in an interpreter as it reports as soon as a bug is caught and restarts the process. This consumes unnecessary memory. Programming Languages like Python, Ruby and Java uses an interpreter.
3. The Device Drivers – The device drivers and the device programs or the system software that acts as an interface between the various Input-Output device and the users or the operating system. For eg., the Printers, Web cameras come with a driver disk that is needed to be installed into the system to make the device run in the system.
4. The BIOS – It stands for Basic Input Output System and is a small firmware, that controls the peripheral or the input-output devices attached to the system. This software is also responsible for starting the OS or initiating the booting process.

Application Software

These are the basic software used to run to accomplish a particular action and task. These are the dedicated software, dedicated to performing simple and single tasks. For eg., a single software cannot serve to both the reservation system and banking system. These are divided into two types:

1. The General Purpose Application Software: These are the types of application software that comes in-built and ready to use, manufactured by some company or someone. For eg.,
   • Microsoft Excel – Used to prepare excel sheets.
   • VLC Media Player – Used to play audio/video files.
   • Adobe Photoshop – Used for designing and animation and many more.
2. The Specific Purpose Application Software: These are the type of software that is customizable and mostly used in real-time or business environment. For eg.,
   • Ticket Reservation System
   • Healthcare Management System
   • Hotel Management System
   • Payroll Management System

Utility Software

These are the most basic type of software which provides high utility to the user and the system. These perform the basic but daily need tasks. For eg.,

• Antivirus Softwares: These provide protection to the computer system from unwanted malware and viruses. For eg., QuickHeal, McAfee etc.
• Disk Defragmenter Tools: These help the users to analyse the bad sectors of the disk and rearrange the files in a proper order.
• Text-editors: These help the users to take regular notes and create basic text files. For eg., Notepad, Gedit etc.

Device Drivers

A device driver is a small piece of software that tells the operating system and other software how to communicate with a piece of hardware.

For example, printer drivers tell the operating system, and by extension whatever program you have the thing you want to print open in, exactly how to print information on the page

sound card drivers are necessary so your operating system knows exactly how to translate the 1s and 0s that comprise that MP3 File  into audio signals that the sound card can output to your headphones or speakers. 

The same general idea applies to video cards, keyboards, monitors, mice, disc drivers, etc.

Keep reading for more on why drivers are important, including some more examples, as well as information on how to keep your drivers updated and what to do if they're not working properly.

Working of Device Driver:
Device Drivers depend upon the Operating System’s instruction to access the device and performing any particular action. After the action they also shows their reactions by delivering output or status/message from hardware device to the Operating system.For Example a printer driver tells the printer in which format to print after getting instruction from OS, similarly A sound card driver is there due to which 1’s and 0’s data of MP3 file is converted to audio signals and you enjoy the music. Card reader, controller, modem, network card, sound card, printer, video card, USB devices, RAM, Speakers etc need Device Drivers to operate.

Office Tools

Office Tools include some Application Software that are used to create, update, manage documents, handle large data, create presentations etc. These tools if used effectively, can save a large amount of time and effort. Lots of repetitive tasks can be done very easily. In this article, we will discuss the following concepts:

• Word Processor
• Presentation Tool
• Spreadsheet Package
• Database Management System

1. Word Processor

Word Processor is a software that is used to manage text documents. User can create, update and formatting text files using word processor. It makes text document related work faster an easier. A word processor is an essential part of any office suite. A word processor usually runs on local machine as a desktop application like Microsoft word but nowadays cloud based Word Processors like Google docs are also used which makes it easier for teams to manage their documents on cloud.

Examples of some word processors are:

• MS-Word: Retail Cross-Platform word processor
• WordPad: Retail windows only word processor
• WordPerfect: Retail Cross-Platform word processor
• Google Docs: Freeware Cloud Based word processor
• LibreOffice Writer: Open Source word processor

Characteristics of word processor:

• Create, save and edit text documents.
• Includes text formatting like font size, alignment, font color, background color, etc.
• Checks spelling.
• Allows adding images, screenshots etc to document.
• Allows adding header and footer, set page margins and insert watermarks to your document.

2. Presentation Tool

A Presentation Tool is a software package used to display data and information in the form of a slide show. The information is broken into small pieces called slides. It has three major parts: editor that allows formatting and editing of text, method used for inserting and manipulating graphic images, screenshots etc, slide-show system to display the content in form of a slide show.

The Slides together are stacked up to make an idea presentable to audience to make up presentation.

Examples of some presentation tool are:

• MS-PowerPoint: Retail Cross-Platform presentation tool
• Lotus Freelance: proprietary software presentation tool
• Google Slides: Freeware Cloud Based presentation tool
• LibreOffice Impress: Open Source presentation tool

3. Spreadsheet Package

Spreadsheet Package is a software that allows users to store, process and modify data in a tabular form easily. It is an accounting tool to manage tabular data. In a Spreadsheet data is always stored in cells. A cell is intersection of rows and columns. functions and formulas can be used easily on cell and data can be processed using a spreadsheet tool.

Examples of some spreadsheet software are:

• MS-Excel: Retail Cross-Platform spreadsheet package
• Google Sheets: Freeware Cloud Based spreadsheet package
• LibreOffice Calc: Open Source spreadsheet package

Characteristics of spreadsheet package:

• User can handle simple calculations like addition, subtraction, average, counting, etc, very easily.
• User can Prepare charts and graphs on a group of data easily.
• Data formatting is efficient and effective.
• Cell formatting is easy.
• Logical Calculations can be done.

4. Database Management System

Database Management System is a software that manages data by storing them in tables to make up a database. A database is an organised collection of data accessed on a machine. A Database Management System interacts with data, users and application. User can store, read, update and can delete data based on his/her needs. A good DBMS provides a set of utilities to administrator to manage the data effectively.

Examples of some Database Management System are:

• MySQL
• PostgreSQL
• Oracle Database
• Microsoft Access.

Characteristics of Database Management System:

• Data storing, reading and updating.
• User accessibility.
• Recovering damaged data facilities.
• Authorization of administrator and data access.
• Defining constraints for dataset.

 

Classification of Computers

The computer systems can be classified on the following basis:

1. On the basis of size.
2. On the basis of functionality.
3. On the basis of data handling.

According to purpose, computers are either general purpose or specific purpose. General purpose computers are designed to perform a range of tasks. They have the ability to store numerous programs, but lack in speed and efficiency. Specific purpose computers are designed to handle a specific problem or to perform a specific task. A set of instructions is built into the machine.

Type of computers on the basis of Functionality & Data Handling:

Analog Computer 

 An analog computer (spelt analogue in British English) is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.

Digital Computer

 A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.

Hybrid computer

Hybrid computers are computers that exhibit features of analog computers and digital computers. The digital component normally serves as the controller and provides logical and numerical operations, while the analog component often serves as a solver of differential equations and other mathematically complex equations.

Type of computers on the basis of Size:

Super Computer 

The fastest and most powerful type of computer Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. Other uses of supercomputers include animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration.

The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.

Mainframe Computer

A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe.

Mini Computer 

A mid sized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from 4 to about 200 users simultaneously.

Micro Computer or Personal Computer

• Desktop Computer: a personal or micro-mini computer sufficient to fit on a desk.

• Laptop Computer: a portable computer complete with an integrated screen and keyboard. It is generally smaller in size than a desktop computer and larger than a notebook computer.

• Palmtop Computer/Digital Diary /Notebook /PDAs: a hand-sized computer. Palmtops have no keyboard but the screen serves both as an input and output devices.

Workstations

A terminal or desktop computer in a network. In this context, workstation is just a generic term for a user’s machine (client machine) in contrast to a “server” or “mainframe.”

 

 

System software

A system software is a specific type of software that manages a computing device. The system software comprises the operating system, utility programmes, and device drivers. We will look at each of the three parts.

The system software is a collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software is generally prepared by the computer manufacturers. These software products comprise of programs written in low-level languages, which interact with the hardware at a very basic level. System software serves as the interface between the hardware and the end users.

Some examples of system software are Operating System, Compilers, Interpreter, Assemblers, etc.

Here is a list of some of the most prominent features of a system software −

• Close to the system
• Fast in speed
• Difficult to design
• Difficult to understand
• Less interactive
• Smaller in size
• Difficult to manipulate
• Generally written in low-level language

AN OPERATING SYSTEM

An operating system is software that manages hardware, software and other applications on a computing device. The operating system has different functions and tasks it carries out on a computing device. In order to make these functions easy to understand, they are grouped into the following categories:

• Disk management: Used to manage the drives installed in a computer e.g. partition drives, format drives, assign drive letters.
• Hardware management: Managing the interaction between hardware and software, as well as the different hardware devices.
• Graphics User Interface (GUI) management: Provides and manages the user interface that interacts with graphics and visual content on a computing device.
• I/O management: Managing the signals received from an input device and sending the correct signals to an output device.
• Process management: Managing the applications and the resources used by applications (Apps) on a computing device.
• File management: Managing the storage of files and folders on your storage device.
• Memory management: Managing the data stored on a computing device’s memory and once the processing is complete, this function tends to free up some space.
• Storage management: Processes used to improve the performance of data storage resources.

Types of operating systems

Up to now, you have been learning about and working with Microsoft Windows as an example of an operating system. This particular type of operating system is commonly known as a stand-alone operating system. In this unit, we will focus on the following three types of operating systems namely, stand-alone, network and embedded operating systems.

THE STAND-ALONE OPERATING SYSTEM

These operating systems function entirely independently from a network on a computer or mobile device. This ensures that the tasks of an operating system can be performed on the device.

THE NETWORK OPERATING SYSTEM

Network or server operating systems are operating systems designed to help computers work together on a network, rather than used in a stand-alone mode. For example, a large company may have a server running the Windows Server operating system in the organisation. A computer can connect to the same network to gain access to its information, resources, etc. Examples include: Windows Server, Red Hat Enterprise, Ubuntu Server, and UNIX.

THE EMBEDDED OPERATING SYSTEM

The embedded operating system is designed for a specific purpose e.g. Smart TVs that connect to the internet, a video camera (Wi-Fi) that can stream live footage and the GPS system that is installed in most mobile devices.

Compiler

A compiler is a special program that processes statements written in a particular programming language and turns them into machine language or "code" that a computer's processor uses. Typically, a programmer writes language statements in a language such as Pascal or C one line at a time using an editor.

Interpreter

In computer science, an interpreter is a computer program that directly executes instructions written in a programming or scripting language, without requiring them previously to have been compiled into a machine language program.

Assembler

An assembler is a program that converts assembly language into machine code. It takes the basic commands and operations from assembly code and converts them into binary code that can be recognized by a specific type of processor. Assemblers are similar to compilers in that they produce executable code.

Difference Between Compiler Interpreter and Assembler

Functionality

Compiler converts the whole high level language program to machine language at a time. Interpreter converts the high level language program to machine language line by line. In contrast, assembler converts assembly language program to machine language.

Language

Languages such as C, C++ use compilers to convert the code. Languages such as Ruby, Perl, Python, PHP uses an interpreter and assembly language uses an assembler.

Conclusion

Compiler, Interpreter and Assembler are language translators. The difference between compiler interpreter and assembler is that compiler converts whole high level language programs to machine language at a time while interpreter converts high level language programs to machine language line by line and assembler converts assembly language programs to machine language.

 

 

 

Utility software

Utility software is software designed to help to analyze, configure, optimize or maintain a computer. It is used to support the computer infrastructure - in contrast to application software, which is aimed at directly performing tasks that benefit ordinary users.

Utility software usually focuses on how the computer infrastructure (including the computer hardware, operating system, software and data storage) operates. Utility software, along with operating system software, is a type of system software, distinguishing it from application software.

• Anti Virus utilities scan for computer viruses.

• Archivers output a stream or a single file when provided with a directory or a set of files. Archive utilities, unlike archive suites, usually do not include compression or encryption capabilities. Some archive utilities may even have a separate un-archive utility for the reverse operation.

• Backup Software can make copies of all information stored on a disk and restore either the entire disk (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion).

• Clipboard Managers expand the clipboard functionality of an operating system .

• Cryptographic utilities encrypt and decrypt streams and files.

• Data Compression utilities output a shorter stream or a smaller file when provided with a stream or file.

• Data Synchronization utilities establish consistency among data from a source to a target data storage and vice versa. There are several branches of this type of utility:

  • File Synchronizatiion utilities maintain consistency between two sources. They may be used to create redundancy or backup copies but are also used to help users carry their digital music, photos and video in their mobile devices.

  • Revision Control utilities are intended to deal with situations where more than one user attempts to simultaneously modify the same file.

• Debuggers are used to test and “debug” other programs, mainly to solve programming errors. Also utilized for reverse engineering of software or systems.

• Disk Checkers can scan operating hard drive.

• Disk Cleaners can find files that are unnecessary to computer operation, or take up considerable amounts of space. Disk cleaner helps the user to decide what to delete when their hard disk is full.

• Disk Compression utilities can transparently compress/uncompress the contents of a disk, increasing the capacity of the disk.

• Disk Defregmenters can detect computer files whose contents are scattered across several locations on the hard disk, and move the fragments to one location to increase efficiency.

• Disk Partitions can divide an individual drive into multiple logical drives, each with its own file system which can be mounted by the operating system and treated as an individual drive.

• Disk Space Analysers for the visualization of disk space usage by getting the size for each folder (including sub folders) & files in folder or drive. showing the distribution of the used space.

• Disk Storage utilities

• File Managers provide a convenient method of performing routine data management tasks, such as deleting, renaming, cataloging, uncataloging, moving, copying, merging, generating and modifying data sets.

• Hex Editiors directly modify the text or data of a file. These files could be data or an actual program.

• Memory Testers check for memory failures.

• Network Utilities analyze the computer’s network connectivity, configure network settings, check data transfer or log events.

• Package Managers are used to configure, install or keep up to date other software on a computer.

• Registry Cleaners clean and optimize the Windows Registry by removing old registry keys that are no longer in use.

• Screensavers were desired to prevent phosphor burn-in on CRT and plasma computer monitors by blanking the screen or filling it with moving images or patterns when the computer is not in use. Contemporary screensavers are used primarily for entertainment or security.

• System Monitors for monitoring resources and performance in a computer system.

• System Profilers provide detailed information about the software installed and hardware attached to the computer.

 

Functions of Operating System

An operating system has three main functions:

(1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers.

(2) establish a user interface.

(3) execute and provide services for applications software.

Operating System supports the basic functions of the computer and is a low-level software. The functions of operating systems are as described below:

i)  I/O Management:

OS manages I/O devices and makes the I/O process effective. OS accepts the input from the input device, stores it in the main memory, ask the CPU to process it and finally provides the result to the output devices for output.

ii) Command Interpreter:

Command interpreter is one of the part of operating system which reads the commands that user types in at a terminal, interprets them and translate them into a detailed set of instructions that the computer hardware can understand. It varies widely from one OS to other OS. Every OS must provide command interpreter for its operation.

iii) Memory Management:

Memory is the large array of words or bytes, each with its own address. When user requests CPU for read/write operation, OS determines the amount of memory required for the program instructions and data. Then, OS allocates required memory to load the program and data into RAM. When program terminates its memory area is free and the same memory area is allocated for other programs.

iv)  Process Management:

OS finds the status of processor and processes, chooses a job, chooses processer in the job, allocates the processor to the process and frees the processor when the process is executed.

v)  Time Sharing:

OS manages the time of CPU. The kernel OS checks frequency for other processes requesting CPU time. Time-sharing checks for CPU request from higher priority processes that are made every 10 milliseconds. When two or more processes at the same priority level are competing for the CPU time, CPU time is sliced into segments, defined by time slice and passed from process to process in a round robin fashion, preventing a single process from monopolizing the CPU until it blocks or terminates.

vi)  Security:

OS makes sure that only authorized users get access to the computer and its data and the users only do things they are authorized to do.

vii) Deadlock Prevention:

During processing, a situation can arise in which a resource shared by two or more processes cannot continue because the resource required by one process is held by the other. This situation is called deadlock. OS ensures that the above condition do not hold by carefully allocating resources.

viii)  Interrupt Handling:

Interrupt is a signal generated from a device or program when they need attention of the CPU. OS determines the type of interrupt and priority of the interrupt, stops the execution process of CPU, preserves the initial state of the CPU, perform the requested operation and brings the CPU at the same state when it was stopped.

ix) Virtual Storage:

If there are programs larger than main memory (RAM) of the computer, OS uses the reserved space in the secondary memory which is termed as virtual memory. It makes the execution of larger program (than RAM) possible but at the same times the operation becomes slower.

Features of Operating System (OS)

Here is a list important features of OS:

• Protected and supervisor mode
• Allows disk access and file systems Device drivers Networking Security
• Program Execution
• Memory management Virtual Memory Multitasking
• Handling I/O operations
• Manipulation of the file system
• Error Detection and handling
• Resource allocation
• Information and Resource Protection

 

 

 

Basics of computer

A computer is a machine that can be instructed to carry out sequences of arithmetic or logical operations automatically via computer programming. Modern computers have the ability to follow generalized sets of operations, called programs. These programs enable computers to perform an extremely wide range of tasks. A "complete" computer including the hardware, the operating system (main software), and peripheral equipment required and used for "full" operation can be referred to as a computer system. This term may as well be used for a group of computers that are connected and work together, in particular a computer network or computer cluster.

Computers are used as control system for a wide variety of industrial and consumer devices. This includes simple special purpose devices like microwave oven and remote contols, factory devices such as industrial robots and computer-aided design, and also general purpose devices like persnol computer and mobile devices such as smartphones. The Internet is run on computers and it connects hundreds of millions of other computers and their users.

Characteristics of Computer

1. Speed: – As you know computer can work very fast. It takes only few seconds for calculations that we take hours to complete. You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second.

Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nanosecond (10 to the power -9 part of a second). From this you can imagine how fast your computer performs work.

2. Accuracy: – The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is 7.

 

determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

3. Diligence: – A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.

4. Versatility: – It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.

5. Power of Remembering: – Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.

 

6. No IQ: – Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can. 

7. No Feeling: – It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users.

8. Storage: – The Computer has an in-built memory where it can store a large amount of data. You can also store data in secondary storage devices such as floppies, which can be kept outside your computer and can be carried to other computers.

Basic Parts of Computer

Computer case

The computer case is the metal and plastic box that contains the main components of the computer, including the motherboard, central processing unit (CPU), and power supply. The front of the case usually has an On/Off button and one or more optical drives.

Computer cases come in different shapes and sizes. A desktop case lies flat on a desk, and the monitor usually sits on top of it. A tower case is tall and sits next to the monitor or on the floor. All-in-one computers come with the internal components built into the monitor, which eliminates the need for a separate case.

Monitor

The monitor works with a video card, located inside the computer case, to display images and text on the screen. Most monitors have control buttons that allow you to change your monitor's display settings, and some monitors also have built-in speakers.

Newer monitors usually have LCD (liquid crystal display) or LED (light-emitting diode) displays. These can be made very thin, and they are often called flat-panel displays. Older monitors use CRT (cathode ray tube) displays. CRT monitors are much larger and heavier, and they take up more desk space.

Keyboard

The keyboard is one of the main ways to communicate with a computer. There are many different types of keyboards, but most are very similar and allow you to accomplish the same basic tasks.

Mouse

The mouse is another important tool for communicating with computers. Commonly known as a pointing device, it lets you point to objects on the screen, click on them, and move them.

There are two main mouse types: optical and mechanical. The optical mouse uses an electronic eye to detect movement and is easier to clean. The mechanical mouse uses a rolling ball to detect movement and requires regular cleaning to work properly.

Mouse alternatives

There are other devices that can do the same thing as a mouse. Many people find them easier to use, and they also require less desk space than a traditional mouse. The most common mouse alternatives are below.

• Trackball: A trackball has a ball that can rotate freely. Instead of moving the device like a mouse, you can roll the ball with your thumb to move the pointer.
• Touchpad: A touchpad—also called a trackpad—is a touch-sensitive pad that lets you control the pointer by making a drawing motion with your finger. Touchpads are common on laptop computers.

Advantages Of Computer

Computer has made a very vital impact on society. It has changed the way of life. The use of computer technology has affected every field of life. People are using computers to perform different tasks quickly and easily. The use of computers makes different task easier. It also saves time and effort and reduces the overall cost to complete a particular task.

Many organizations are using computers for keeping the records of their customers. Banks are using computers for maintaining accounts and managing financial transactions. The banks are also providing the facility of online banking. The customers can check their account balance from using the internet. They can also make financial transaction online. The transactions are handled easily and quickly with computerized systems.

People are using computers for paying their bills, managing their home budgets or simply having some break and watching a movie, listening to songs or playing computer games. Online services like skype or social media websites are used for communication and information sharing purposes.

Computer can be used as a great educational tool. Students can have access to all sort of information on the internet. Some great websites like Wikipedia, Khan’s Academy, Code Academy, Byte-Notes provides free resources for students & professionals. 

Disadvantages Of Computer

The use of computer has also created some problems in society which are as follows.

Unemployment

Different tasks are performed automatically by using computers. It reduces the need of people and increases unemployment in society.

Wastage Of Time And Energy

Many people use computers without positive purpose. They play games and chat for a long period of time. It causes wastage of time and energy. Young generation is now spending more time on the social media websites like Facebook, Twitter etc or texting their friends all night through smartphones which is bad for both studies and their health. And it also has adverse effects on the social life.

Data Security

The data stored on a computer can be accessed by unauthorized persons through networks. It has created serious problems for the data security.

Computer Crimes

People use the computer for negative activities. They hack the credit card numbers of the people and misuse them or they can steal important data from big organizations.

Privacy Violation

The computers are used to store personal data of the people. The privacy of a person can be violated if the personal and confidential records are not protected properly.

Health Risks

The improper and prolonged use of computer can results in injuries or disorders of hands, wrists, elbows, eyes, necks and back. The users can avoid health risks by using the computer in proper position. They must also take regular breaks while using the computer for longer period of time. It is recommended to take a couple of minutes break after 30 minutes of computer usage.

Impact On Environment

The computer manufacturing processes and computer waste are polluting the environment. The wasted parts of computer can release dangerous toxic materials. Green computer is a method to reduce the electricity consumed and environmental waste generated when using a computer. It includes recycling and regulating manufacturing processes. The used computers must be donated or disposed off properly.

 

SYSTEM SOFTWARE

As you know, system software acts as an interface for the underlying hardware system. Here we will discuss some important system software in detail.

Operating System

Operating system (OS) is the lifeline of computer. You connect all the basic devices like CPU, monitor, keyboard and mouse; plug in the power supply and switch it on thinking you have everything in place. But the computer will not start or come to life unless it has an operating system installed in it because OS 

•  Keeps all hardware parts in a state of readiness to follow user instructions
•  Co-ordinates between different devices
•  Schedules multiple tasks as per priority
•  Allocates resource to each task
•  Enables computer to access network
•  Enables users to access and use application software

Besides initial booting, these are some of the functions of an operating system 

•  Managing computer resources like hardware, software, shared resources, etc.
•  Allocating resources
•  Prevent error during software use
•  Control improper use of computer

One of the earliest operating systems was MS-DOS, developed by Microsoft for IBM PC. It was a Command Line Interface (CLI) OS that revolutionized the PC market. DOS was difficult to use because of its interface. The users needed to remember instructions to do their tasks. To make computers more accessible and user-friendly, Microsoft developed Graphical User Interface (GUI) based OS called Windows, which transformed the way people used computers.

Assembler

Assembler is a system software that converts assembly level programs to machine level code.

These are the advantages provided by assembly level programming 

•  Increases efficiency of the programmer as remembering mnemonics is easier
•  Productivity increases as number of errors decreases and hence debugging time
•  Programmer has access to hardware resources and hence has flexibility in writing programs customized to the specific computer

Interpreter

The major advantage of assembly level language was its ability to optimize memory usage and hardware utilization. However, with technological advancements computers had more memory and better hardware components. So ease of writing programs became more important than optimizing memory and other hardware resources.

In addition, a need was felt to take programming out of a handful of trained scientists and computer programmers, so that computers could be used in more areas. This led to development of high level languages that were easy to understand due to resemblance of commands to English language.

The system software used to translate high level language source code into machine level language object code line by line is called an interpreter. An interpreter takes each line of code and converts it into machine code and stores it into the object file.

The advantage of using an interpreter is that they are very easy to write and they do not require a large memory space. However, there is a major disadvantage in using interpreters, i.e., interpreted programs take a long time in executing. To overcome this disadvantage, especially for large programs, compilers were developed.

Compiler

System software that store the complete program, scan it, translate the complete program into object code and then creates an executable code is called a compiler. On the face of it compilers compare unfavorably with interpreters because they 

•  are more complex than interpreters
•  need more memory space
•  take more time in compiling source code

However, compiled programs execute very fast on computers. The following image shows the step-by-step process of how a source code is transformed into an executable code 

These are the steps in compiling source code into executable code 

•  Pre-processing : In this stage pre-processor instructions, typically used by languages like C and C++ are interpreted, i.e. converted to assembly level language.

•  Lexical analysis : Here all instructions are converted to lexical units like constants, variables, arithmetic symbols, etc.

•  Parsing : Here all instructions are checked to see if they conform to grammar rules of the language. If there are errors, compiler will ask you to fix them before you can proceed.

•  Compiling : At this stage the source code is converted into object code.

•  Linking : If there are any links to external files or libraries, addresses of their executable will be added to the program. Also, if the code needs to be rearranged for actual execution, they will be rearranged. The final output is the executable code that is ready to be executed.

SOFTWARE CONCEPT

As you know, the hardware devices need user instructions to function. A set of instructions that achieve a single outcome are called program or procedure. Many programs functioning together to do a task make a software.

For example, a word-processing software enables the user to create, edit and save documents. A web browser enables the user to view and share web pages and multimedia files. There are two categories of software 

•  System Software
•  Application Software
•  Utility Software

Let us discuss them in detail.

System Software

Software required to run the hardware parts of the computer and other application software are called system software. System software acts as interface between hardware and user applications. An interface is needed because hardware devices or machines and humans speak in different languages.

Machines understand only binary language i.e. 0 (absence of electric signal) and 1 (presence of electric signal) while humans speak in English, French, German, Tamil, Hindi and many other languages. English is the pre-dominant language of interacting with computers. Software is required to convert all human instructions into machine understandable instructions. And this is exactly what system software does.

Based on its function, system software is of four types 

•  Operating System
•  Language Processor
•  Device Drivers

Operating System

System software that is responsible for functioning of all hardware parts and their interoperability to carry out tasks successfully is called operating system (OS). OS is the first software to be loaded into computer memory when the computer is switched on and this is called booting. OS manages a computer’s basic functions like storing data in memory, retrieving files from storage devices, scheduling tasks based on priority, etc.

Language Processor

As discussed earlier, an important function of system software is to convert all user instructions into machine understandable language. When we talk of human machine interactions, languages are of three types 

• Machine-level language: This language is nothing but a string of 0s and 1s that the machines can understand. It is completely machine dependent.

•  Assembly-level language: This language introduces a layer of abstraction by defining mnemonics. Mnemonics are English like words or symbols used to denote a long string of 0s and 1s. For example, the word “READ” can be defined to mean that computer has to retrieve data from the memory. The complete instruction will also tell the memory address. Assembly level language is machine dependent.

•  High level language: This language uses English like statements and is completely independent of machines. Programs written using high level languages are easy to create, read and understand.

Program written in high level programming languages like Java, C++, etc. is called source code. Set of instructions in machine readable form is called object code or machine code. System software that converts source code to object code is called language processor. There are three types of language interpreters

•  Assembler: Converts assembly level program into machine level program.

•  Interpreter: Converts high level programs into machine level program line by line.

•  Compiler: Converts high level programs into machine level programs at one go rather than line by line.

Device Drivers

System software that controls and monitors functioning of a specific device on computer is called device driver. Each device like printer, scanner, microphone, speaker, etc. that needs to be attached externally to the system has a specific driver associated with it. When you attach a new device, you need to install its driver so that the OS knows how it needs to be managed.

Application Software

A software that performs a single task and nothing else is called application software. Application software are very specialized in their function and approach to solving a problem. So a spreadsheet software can only do operations with numbers and nothing else. A hospital management software will manage hospital activities and nothing else. Here are some commonly used application software 

•  Word processing
•  Spreadsheet
•  Presentation
•  Database management
•  Multimedia tools

Utility Software

Application software that assist system software in doing their work is called utility software. Thus utility software is actually a cross between system software and application software. Examples of utility software include 

•  Antivirus software
•  Disk management tools
•  File management tools
•  Compression tools
•  Backup tools

CLASSIFiCATION

Historically computers were classified according to processor types because development in processor and processing speeds were the developmental benchmarks. Earliest computers used vacuum tubes for processing, were huge and broke down frequently. However, as vacuum tubes were replaced by transistors and then chips, their size decreased and processing speeds increased manifold.

All modern computers and computing devices use microprocessors whose speeds and storage capacities are skyrocketing day by day. The developmental benchmark for computers is now their size. Computers are now classified on the basis of their use or size.

•  Desktop
•  Laptop
•  Tablet
•  Server
•  Mainframe
•  Supercomputer

Let us look at all these types of computers in detail.

Desktop

Desktop computers are personal computers (PCs) designed for use by an individual at a fixed location. IBM was the first computer to introduce and popularize use of desktops. A desktop unit typically has a CPU (Central Processing Unit), monitor, keyboard and mouse. Introduction of desktops popularized use of computers among common people as it was compact and affordable.

Riding on the wave of desktop’s popularity many software and hardware devices were developed specially for the home or office user. The foremost design consideration here was user friendliness.

Laptop

Despite its huge popularity, desktops gave way to a more compact and portable personal computer called laptop in 2000s. Laptops are also called notebook computers or simply notebooks. Laptops run using batteries and connect to networks using Wi-Fi (Wireless Fidelity) chips. They also have chips for energy efficiency so that they can conserve power whenever possible and have a longer life.

Modern laptops have enough processing power and storage capacity to be used for all office work, website designing, software development and even audio/video editing.

Tablet

After laptops computers were further miniaturized to develop machines that have processing power of a desktop but are small enough to be held in one’s palm. Tablets have touch sensitive screen of typically 5 to 10 inches where one finger is used to touch icons and invoke applications.

Keyboard is also displayed virtually whenever required and used with touch strokes. Applications that run on tablets are called apps. They use operating systems by Microsoft (Windows 8 and later versions) or Google (Android). Apple computers have developed their own tablet called iPad which uses a proprietary OS called iOS.

Server

Servers are computers with high processing speeds that provide one or more services to other systems on the network. They may or may not have screens attached to them. A group of computers or digital devices connected together to share resources is called a network.

Servers have high processing powers and can handle multiple requests simultaneously. Most commonly found servers on networks include 

•  File or storage server
•  Game server
•  Application server
•  Database server
•  Mail server
•  Print server

Mainframe

Mainframes are computers used by organizations like banks, airlines and railways to handle millions and trillions of online transactions per second. Important features of mainframes are 

•  Big in size
•  Hundreds times Faster than servers, typically hundred megabytes per second
•  Very expensive
•  Use proprietary OS provided by the manufacturers
•  In-built hardware, software and firmware security features

Supercomputer

Supercomputers are the fastest computers on Earth. They are used for carrying out complex, fast and time intensive calculations for scientific and engineering applications. Supercomputer speed or performance is measured in teraflops, i.e. 1012 floating point operations per second.

Chinese supercomputer Sunway TaihuLight is the world’s fastest supercomputer with a rating of 93 petaflops per second, i.e. 93 quadrillion floating point operations per second.

Most common uses of supercomputers include 

•  Molecular mapping and research
•  Weather forecasting
•  Environmental research
•  Oil and gas exploration

INTRODUCTION TO COMPUTER

Being a modern-day kid you must have used, seen, or read about computers. This is because they are an integral part of our everyday existence. Be it school, banks, shops, railway stations, hospital or your own home, computers are present everywhere, making our work easier and faster for us. As they are such integral parts of our lives, we must know what they are and how they function. Let us start with defining the term computer formally.

The literal meaning of computer is a device that can calculate. However, modern computers can do a lot more than calculate. Computer is an electronic device that receives input, stores or processes the input as per user instructions and provides output in desired format.

Input-Process-Output Model

•  Computer input is called data and the output obtained after processing it, based on user’s instructions is called information. Raw facts and figures which can be processed using arithmetic and logical operations to obtain information are called data.

The processes that can be applied to data are of two types

•  Arithmetic operations: Examples include calculations like addition, subtraction, differentials, square root, etc.

•  Logical operations: Examples include comparison operations like greater than, less than, equal to, opposite, etc.

The corresponding figure for an actual computer looks something like this

The basic parts of a computer are as follows

•  Input Unit: Devices like keyboard and mouse that are used to input data and instructions to the computer are called input unit.

•  Output Unit: Devices like printer and visual display unit that are used to provide information to the user in desired format are called output unit.

•  Control Unit: As the name suggests, this unit controls all the functions of the computer. All devices or parts of computer interact through the control unit.

•  Arithmetic Logic Unit: This is the brain of the computer where all arithmetic operations and logical operations take place.

•  Memory: All input data, instructions and data interim to the processes are stored in the memory. Memory is of two types primary memory and secondary memory. Primary memory resides within the CPU whereas secondary memory is external to it.

Control unit, arithmetic logic unit and memory are together called the central processing unit or CPU. Computer devices like keyboard, mouse, printer, etc. that we can see and touch are the hardware components of a computer. The set of instructions or programs that make the computer function using these hardware parts are called software. We cannot see or touch software. Both hardware and software are necessary for working of a computer.

Characteristics of Computer

To understand why computers are such an important part of our lives, let us look at some of its characteristics

•  Speed: Typically, a computer can carry out 3-4 million instructions per second.

•  Accuracy: Computers exhibit a very high degree of accuracy. Errors that may occur are usually due to inaccurate data, wrong instructions or bug in chips all human errors.

•  Reliability: Computers can carry out same type of work repeatedly without throwing up errors due to tiredness or boredom, which are very common among humans.

•  Versatility: Computers can carry out a wide range of work from data entry and ticket booking to complex mathematical calculations and continuous astronomical observations. If you can input the necessary data with correct instructions, computer will do the processing.

•  Storage Capacity: Computers can store a very large amount of data at a fraction of cost of traditional storage of files. Also, data is safe from normal wear and tear associated with paper.

Advantages of Using Computer

Now that we know the characteristics of computers, we can see the advantages that computers offer−

•  Computers can do the same task repetitively with the same accuracy.

•  Computers do not get tired or bored.

•  Computers can take up routine tasks while releasing human resource for more intelligent functions.

Disadvantages of Using Computer

Despite so many advantages, computers have some disadvantages of their own

•  Computers have no intelligence; they follow the instructions blindly without considering the outcome.

•  Regular electric supply is necessary to make computers work, which could prove difficult everywhere especially in developing nations.

Booting

Starting a computer or a computer-embedded device is called booting. Booting takes place in two steps

•  Switching on power supply
•  Loading operating system into computer’s main memory
•  Keeping all applications in a state of readiness in case needed by the user

The first program or set of instructions that run when the computer is switched on is called BIOS or Basic Input Output System. BIOS is a firmware, i.e. a piece of software permanently programmed into the hardware.

If a system is already running but needs to be restarted, it is called rebooting. Rebooting may be required if a software or hardware has been installed or system is unusually slow.

There are two types of booting

•  Cold Booting: When the system is started by switching on the power supply it is called cold booting. The next step in cold booting is loading of BIOS.

•  Warm Booting: When the system is already running and needs to be restarted or rebooted, it is called warm booting. Warm booting is faster than cold booting because BIOS is not reloade.

AntiVirus

Antivirus software is designed to find known viruses and oftentimes other malware such as Ransomware, Trojan Horses, worms, spyware, adware, etc., that can have a detrimental impact to the user or device.

Antivirus programs provide a way to protect against known threats. The effectiveness of an antivirus program is heavily dependent on how often it is updated. Therefore, it is important to have the antivirus program scheduled to update daily.  Most antivirus programs rely on a library or database of known viruses that they use to compare with programs on a user’s device. If a match is found, the malicious program will either be deleted or placed into a quarantine area from which a user can decide to restore or delete the program manually.

One limitation of traditional antivirus programs is that they only provide protection against known threats. Therefore, if someone cooks up new malicious code, an antivirus program may fail to detect it when a scan is done. Users should not consider an antivirus program to be universal protection against all viruses and malware. Instead, users should consider an antivirus program to be one part of a comprehensive online security hygiene regimen. Security experts refer to this aspect of information security as Endpoint Protection.

There are some antivirus manufacturers that are incorporating predictive analysis and artificial intelligence into their antivirus software to be able to detect new malicious programs. They focus on detecting malicious software based on what it does, as opposed to whether it exists in a library or dictionary. While we cannot recommend one antivirus program over another, we encourage users to do independent research to find which antivirus program will work best for them.

Have you ever downloaded a file, opened it and been a victim of excessive pop-ups thereafter? Chances are the file installed an adware program on your computer when you opened it. An antivirus program could have stopped this if:

1. The malicious software was known to the antivirus company. 
2. The antivirus program was up to date.

This example showcases the strengths and weaknesses of antivirus programs. They are very efficient at what they do, but they will only protect against malicious programs that are known, and only if kept updated. The good news is, there are countless types of malicious software that antivirus companies know about, and they are becoming more and more efficient at discovering new varieties every day.

We recommend that users take several steps to avoid infection by a virus or malware.

1. The first step a user must make is to decide which antivirus program will be best for them. There are many free and paid versions of antivirus programs available. We encourage users to examine trusted sources or reviews of different antivirus programs.
2. When installing the antivirus program, it is best to set up scheduled updates. The antivirus program will usually prompt you during the setup process to schedule a certain time or frequency for updates. We recommend a daily update at a time when your computer will be on but not in use. It is also a good idea to have a thorough first scan to remove any viruses or malware that may already be on the device.
3. Ensure scans are performed at regular intervals. We recommend daily scans at a time when you are not using the device.
4. If you are using a paid antivirus program, it is important to ensure the subscription is renewed to avoid gaps in coverage.
5. Finally, be careful what sites you visit. All an attacker needs is for you to land on their dirty page. Visit only reputable sites.

With an antivirus program configured with regular updates and scans, users should feel safe from known threats. Antivirus programs are a key part to a user’s total cybersecurity hygiene practice.

Advantages

1. Virus Protection

The main role of an antivirus program is to stand against viruses and other forms of malwares. The viruses will not only cause damages to your data, it can degrade the overall system performance. All of them can happen without your knowledge. The antivirus software installed on your computer detects and removes these malwares before they cause any harms to your computer.


2. Spyware Protection

Spyware as the name suggests is a kind of malware that spies on your computer stealing all the confidential informations. These details also include credit card details, passwords and other financial datas. This ultimately leads to identity theft. The antivirus software has the capability to prevent these kinds of spyware attacks.


3. Web Protection

While surfing the internet, users can come across various other forms of threats. In an untrustworthy sites, cyber attackers can gather your credit card and bank account details. One of the way to overcome this is by using an antivirus software. Using antivirus program you can protect your valuable informations while surfing the web.


4. Spam Protection

Viruses can also enter your computer through means of spam emails and ads. These emails and ads can show up many times even if your have no interest in it. Once the virus finds the way to sneak into your PC it cause irreversible damages. An Antivirus works by the way of blocking these spam emails and ads.


5. Firewall Feature

Most antivirus programs include a firewall feature in them. Antivirus program with firewall feature ensures 2 way protection to your PC. This means that whatever the information that is sent or received will be double checked here. Therefore, no hackers can dig any personal informations from your system.


6. Cost Effective

Even thought there are many premium versions of antivirus programs for a monthly/yearly subscription fee, there are some antivirus programs those are completely free of charge. These kinds of antivirus programs offer almost the same level of protection provided by the subscription based. Even if you choose to afford a premium version, they are relatively inexpensive.

Disadvantages

1. System Slowdown

Using an antivirus program means that a lot of resources from the memory and the hard drive is being used. As a result it can drastically slowdown overall speed of the computer. Moreover, the process of scanning can also cause lags in the network.


2. No Complete Protection

If you are using a free antivirus program, there is no guarantee that it will provide you the complete protection. Most free antivirus programs out there only offer a basic level of protection. Moreover they are capable of identifying only certain types of threats. In order for acquiring complete level of protection, you have to use a firewall as well.


3. Security Holes

When security holes are present inside the operating system or the networking software, it will provide a chance for the virus to bypass the antivirus software. Unless the user takes actions to keep it update, the antivirus software won't be effective.


4. Limited Detection Techniques

For identifying a potential threat, there are always more than one method available. However in the case of antivirus program, it mostly executes the method of virus scanning. Basically what happens in the process of scanning is, it will try to search for the virus code patterns. Sometimes the antivirus programs can give you false alarms if the scanning matches with the normal file. Furthermore, if there are any new types of viruses the antivirus program will fail to identify it completely. That is the reason why antivirus software needs to be updated often.


5. Frequent Advertisements

Apart from premium versions of antivirus programs, through some means the free antivirus softwares needs to generate an income. Advertising is one of the ways to achieve them. Many at times these advertisements degrade user experience by showing up every time.


6. No Customer Support

Another drawback of a free antivirus program is that it lacks on the side of customer support. Unless you pay for the premium version, there won't be any customer support given to you. In the event of any problem, the only way to overcome is through forums and knowledge bases.

 

 

What is computer security?

Computer security basically is the protection of computer systems and information from harm, theft, and unauthorized use. It is the process of preventing and detecting unauthorized use of your computer system.

There are various types of computer security which is widely used to protect the valuable information of an organization.

What is Computer Security and its types?

One way to ascertain the similarities and differences among Computer Security is by asking what is being secured. For example,

• Information Security is securing information from unauthorized access, modification & deletion
• Application Security is securing an application by building security features to prevent from Cyber Threats such as SQL injection, DoS attacks, data breaches and etc.
• Computer Security means securing a standalone machine by keeping it updated and patched
• Network Security is by securing both the software and hardware technologies
• Cybersecurity is defined as protecting computer systems, which communicate over the computer networks

It’s important to understand the distinction between these words, though there isn’t necessarily a clear consensus on the meanings and the degree to which they overlap or are interchangeable.

 

So, Computer security can be defined as controls that are put in place to provide confidentiality, integrity, and availability for all components of computer systems. Let’s elaborate the definition.

Components of computer system

The components of a computer system that needs to be protected are:

• Hardware, the physical part of the computer, like the system memory and disk drive
• Firmware, permanent software that is etched into a hardware device’s nonvolatile memory and is mostly invisible to the user
• Software, the programming that offers services, like operating system, word processor, internet browser to the user 

Computer security threats

Computer security threats are possible dangers that can possibly hamper the normal functioning of your computer. In the present age, cyber threats are constantly increasing as the world is going digital. The most harmful types of computer security are:

Viruses

A computer virus is a malicious program which is loaded into the user’s computer without user’s knowledge. It replicates itself and infects the files and programs on the user’s PC. The ultimate goal of a virus is to ensure that the victim’s computer will never be able to operate properly or even at all. 

Computer Worm

A computer worm is a software program that can copy itself from one computer to another, without human interaction. The potential risk here is that it will use up your computer hard disk space because a worm can replicate in greate volume and with great speed.

Phishing

Disguising as a trustworthy person or business, phishers attempt to steal sensitive financial or personal information through fraudulent email or instant messages. Phishing in unfortunately very easy to execute. You are deluded into thinking it’s the legitimate mail and you may enter your personal information.

Botnet

A botnet is a group of computers connected to the internet, that have been compromised by a hacker using a computer virus. An individual computer is called ‘zombie computer’. The result of this threat is the victim’s computer, which is the bot will be used for malicious activities and for a larger scale attack like DDoS.

Rootkit

A rootkit is a computer program designed to provide continued privileged access to a computer while actively hiding its presence. Once a rootkit has been installed, the controller of the rootkit will be able to remotely execute files and change system configurations on the host machine.

Keylogger

Also known as a keystroke logger, keyloggers can track the real-time activity of a user on his computer. It keeps a record of all the keystrokes made by user keyboard. Keylogger is also a very powerful threat to steal people’s login credential such as username and password.

Why is Computer Security Important?

In this digital era, we all want to keep our computers and our personal information secure and hence computer security is important to keep our personal information protected. It is also important to maintain our computer security and its overall health by preventing viruses and malware which would impact on the system performance.

Computer Security Practices

Computer security threats are becoming relentlessly inventive these days. There is much need for one to arm oneself with information and resources to safeguard against these complex and growing computer security threats and stay safe online. Some preventive steps you can take include:

• Secure your computer physically by:
  • Installing reliable, reputable security and anti-virus software
  • Activating your firewall, because a firewall acts as a security guard between the internet and your local area network 
• Stay up-to-date on the latest software and news surrounding your devices and perform software updates as soon as they become available
• Avoid clicking on email attachments unless you know the source 
• Change passwords regularly, using a unique combination of numbers, letters and case types
• Use the internet with caution and ignore pop-ups, drive-by downloads while surfing
• Taking the time to research the basic aspects of computer security and educate yourself on evolving cyber-threats
• Perform daily full system scans and create a periodic system backup schedule to ensure your data is retrievable should something happen to your computer.