Computer Security

Computer security refers to the protection of the computer’s resources from accidental, intentional or natural disasters, including theft, physical damage, heat power management, illegal access, data piracy, virus infection, etc.

Computer security can be studied under two major categories:
       1. Hardware security
       2. Software security

* Hardware Security

    Hardware security refers to the protection of computers hardware resources from physical loss or damage.

Hardware Security Measures:
1. Computers should be kept in an appropriate temperature i.e. the        

     room temperature should be maintained in between 18 to 24                                               degree Celsius for older system and between 0 to 40 degree Celsius for modern system otherwise the system may cease to work.

2. The computers room should be clean, bright, dust/smoke free, dry and well ventilated.

• Software security

             Software security refers to the protection of computers software resource from being pirated, deleted, corrupted, infected from viruses, etc.

Software Security Measures

1. Operating system/ network system with adequate automatic protection capabilities and system security measures should be used.
2. Operating system and application programs should be virus free and safety measures to stop virus infiltration should be adopted.

      

Computer Database

Database which is a collection or well organized and structured information is found in almost all the organizations whether it is school, college, Business Company, government or private offices, etc. Database is very important for carrying any kind of business or activities.

The telephone directory of your city; the railway time table or library catalogues are large collections of information. The telephone directory gives information about names, addresses and telephone numbers of people, the railway time table gives information about routes and timings of trains, while a library catalogue has information regarding all the books available in the library- title, author, publisher, edition, or which shelf it is available on. Each of the above collections of information is called database. A system that manages data, i.e. organizes, processes, and retrieves data, is called a database management system. In early days when there were no computers, handling of database were all done manually, which faced many problems.

Advantages of a Computer Database

The shortcomings of a manual database management system can be overcome to an extent by maintaining the database management so it helps to store, organize process and retrieve information much more efficiently. Some of its advantages are listed below:

- Large amounts of information can be stored easily on computers.

- All data is in one place. The same database can be accessed by people located different places.

- The database can be regularly updated from a single place. Hence there is no confusion about someone having the latest information and others not having it.

- The same database can be used to access information in different ways. A telephone database maintained on a computer will make it possible for us to find out   someone's telephone number from the first name or the address, or to find the name and address of a person whose telephone number is known.

- Any number of different reports can be generated quickly from one database.

Quick Basic (Q basic)

Quick Basic (Q Basic) is a language developed by Microsoft, USA.  Quick Basic is a high level language. This language provides more powerful tools than GW-BASIC for writing, editing, running and debugging programs.  Its also provides online help when required.  This language has no doubt an edge over BASIC.  One of the important differences is that Quick Basic is faster than BASIC.  The second difference is that it is more flexible than BASIC and also provides more advanced features than BASIC.  Because of these qualities Quick Basic has gained popularity in many fields.  Quick Basic eliminates the confusing line of codes for every instruction that is compulsory in BASIC.

Features of Q Basic

1)      It provides online help whenever required.

2)      Quick Basic has a built in editor.  This editor provides different options to effectively make programs writing easy, to debug programs or to modify programs.  It also provides the facility of importing program parts.

3)      A single program can be divided into different parts, each part doing an independent task.  In fact, the set of instructions which carry out the task can be grouped together.  These are called’ function’ or ‘producers’.  Quick Basic allows these types of modules to define in a program.

4)      Most of the time in programming, different tasks is to be carried out depending on different conditions. These conditions have to be checked first of all before carrying out the action.

Introduction to windows xp operating system of the computer

The Windows XP o/s is the most widely used operating system for desktop and laptop computer. Its was developed by Microsoft Coporation, USA. Windows provides a graphical user interface and desktop environment in which applications are in resizable, movable windows on screen.

The previous client version of Windows XP was a major upgrade to the client version of Windows 2000 with numerous changes to the user interface. XP improved support for gaming, digital photography, instant messaging, wireless networking and sharing connections to the Internet. 

Features OF Windows…………………

1)      It is a multitasking operating system where multiple programs can be run at the same time. The operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn.

2)      It manages the sharing of internal memory among multiple applications.

3)      It handles input and output to and from attached hardware devices, such as hard disks, printers, and dial-up ports.

4)      It sends messages to each application or interactive user (or to system operator) about the status of operation and any errors that may have occurred.

5)      Windows GUI feature provides user friendly environment.

Computer Networking

A computer network links two or more computers so that they can exchange data and share resources including expensive peripherals such as high -performance laser printers. Let us consider a situation in which many people in an organization need to work with the same data. A copy of data can be loaded in each computer so that the employee can access the data individually. However, a more efficient method is to load the data on one computer and provide the other computers access to the data from this computer remotely. This option saves disk space on the computers and provides a central location for storing and managing the data that multiple users need to access. In other words computer network is a group of computers and associated peripherals connected by a communications channel capable of sharing files and other resources between several users.


Type of computer network: -

 Today’s computer networks include computers and computer operating system associated with all of the computing models. A typical network includes main frame, personal computers, and a variety of other computers and communicating devices. Computer network fit the general definition of networking since they share electronic data and computing devices. Computer networks are often classified by size, distance covered or structure. Even though the distinctions are rapidly fading, the following network classifications are commonly used:

A.       Local Area Network(LAN)

B.       Metropolitan Area network(MAN)

C.        Wide Area Network(WAN)

Computer Languages

A computer actually cannot perform any task automatically, as it does not have any thinking power like human. Computers are just machine or tools. We must instruct or teach them to do all the jobs we want to do. The basic task of a computer is to solve problems and process data provided by us. Computers cannot solve problems on their own. They do what we teach or tell them to do. They do not have reasoning ability of their own. So, we have to provide instructions to computers to carry out a given task. We use languages to communicate with one another. No communication is possible without a language.
Computer Language in Detail
There are many languages used to communicate with the computers and they are simpler in structure. One statement conveys only one message to the computer, which makes the computer language precise. They have strict grammar and have very few rules compared to natural languages.
We communicate to the computer in form of instructions and data and the computer does the same with the results. We provide instructions to solve a particular problem and a computer solves it according to our instructions.
Computer language is an artificial language that specifies instructions to be executed on a computer.
Based on the nature of the languages, they are divided mainly in two categories:

A.     Low Level Languages: -

Low level languages are the languages, which are machine oriented, i.e. they are easily understood by computers compared to human.

B.     High Level Languages: -

There are many high level languages in use today. They take less time to program and the programs written in them can be transported from one computer to another without having to make changes. The use of these languages reduces the need to have a detailed knowledge of the computer architecture as opposed to low level languages. Therefore example: BASIC, COLBOL, FORTAIN, C, C⁺⁺⁺, etc.

Computer Virus

A computer virus is a program that attaches itself to, overwrites and/or otherwise replaces another program in order to reproduce itself without the knowledge of the computer user. Generally, the first thing a virus does is attach itself to other files in such a way that the virus code is in effect when the infected files are run. Viruses may be written to multiply, to damage other programs or to alter certain data.

A computer virus is nothing more than a computer program that is coded to remain hidden in your computer. The virus takes advantage of operating system to copy itself onto other files or disks. When a new disk is inserted into an infected computer, the virus than copies itself onto files on that disk. When an infected disk is inserted into another computer, the virus than copies itself onto files on that computer’s hard drive. The cycle continues as long as files are shared between computers.

Booting your computer with an infected floppy disk is one of the most common ways of catching a virus. Downloading a file from the Internet or an online service is another common way of catching a computer virus. Most reputable Internet sites and online services now scan all their files for virus but that still does guarantee that all their files will be virus free. You can also catch computer viruses from E-mail attachments.  While you cannot catch a virus from simply reading an E-mail message, viruses can be spread through programs or office application files that may be sent as attachments to E-mails.  Always save and scan E-mail attachment for viruses before opening the attachment

The most important thing you should do to protect your system and your data is to install a reputable anti-virus program on your computer. There are many companies that currently provide this type of software and many of them offer free downloadable trial versions from their web sites.  All anti-virus software have different options or settings that you can select to optimize its scanning properties.  Many anti-virus programs now also offer the ability to automatically scan any file you download from the Internet or any file that you may receive as an attachment to E-mail.

In order for your anti-virus software to remain effective, you must update it regularly for the simple fact that there are new viruses being introduced at an alarming rate.  All anti-viruses software companies offer regular updates to combat these new viruses. Some offer these updates free from the Internet once you purchase their software, and some charge a fee for their updates. This is something to consider as you shop around for yours anti-virus software.  No anti-virus software is 100% effective. Therefore any anti-virus protection strategy should also include regular back-ups of your data.  This won’t prevent any viruses but it will reduce your computers down time if you ever catch one. There may be some other problem causing erratic behaviour of computer.  Computer viruses are not always responsible for the damage of computers. Damage to hardware, such as Keyboards and monitors are not caused by viruses.  Though you may experience strange behaviours such as screen distortion or characters not appearing when typed, a virus has, in fact, merely affected the programs that control the display or keyboard. Not even your disks themselves are physically damaged; just what’s stored on them. Viruses can only infect files and corrupt data.

While very few people actually seen a computer virus, they are real and they are here to stay. As the software companies develop new improved methods to combat viruses, new viruses appear to defeat them. In conclusion, one fact remains. If you are one of the millions of computer users surfing internet or uploading files from disks, you need to be aware of the threat of computer viruses and protect yourself accordingly.