7th Class

    Introduction to UNIX   UNIX is one of the time sharing operating systems primarily intended for program development and document-preparation environment. The first version of UNIX was written by Ten Thompson, later joined by Dennis Ritchie. It was a single user system written for the PDP-7 computer written in assembly language. Several specialized versions of UNIX, such as the programmer's Workbench, UNIX/ PWB and Writer's Workbench, UNIX/WWB are also available.       Some of the major features of UNIX are the following:

• Hierarchical file system.
• Device Independence.
• Multi-user operation.
• Tools and tool-building utilities.
• Probability.    

     

• In 1985 the first version of Windows was released in market.
• iPod, iPhone, and iPad all are developed by Apple.
• Steve Jobs established Apple in April 1976.  
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   Introduction to Windows vista   In the series of an operating system, windows launched its new version in comparison to other operating system of windows. Windows Vista is one of the highly security proof operating systems, its basic qualities are the following:

• Organizes files in a new way.
• Searches from within the folders.    
• Keeps devices in synchronized manner.
• Backups and encrypts files.
• Faxes and scans documents.
• Views, edits and organizes pictures.
• Uses improved networking features.
• Provides guidance with parental controls.  

 

     Introduction to Operating System     Operating system is a program which acts as an interface between a computer hardware and a user of the computer. It provides such an environment in which a user may execute programs. Basically there are two goals of an operating system, the primary goal is to make computer system convenient to use and a secondary goal is to use the computer hardware in an effective manner. OS helps in file management, program execution, system management and memory management. The internal structure of operating system is divided into three layers. The outermost layer is called user interface and innermost layer is hardware.                        The following are the main layers in OS:

• Kernel
• Shell
• User Interface  

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     Treatment of Wastewater   Disposal of waste water in water bodies pollutes the water bodies. To cope up with this pollution of water bodies, treatment or cleaning of waste water is done. However, due to increasing population, the more and more sewage is generated and therefore, the cleaning process is not adequately able to handle all the generated waste water.                Treatment of Municipal Waste Water Sewage is carried from sewers to a sewage treatment plant. In the sewage treatment plant, strainers separate large solids such as leaves, rags, plastic, etc.   Then the sewage is passed to settlement tank to settle down the suspended solids to the bottom. The solids settled at the bottom of more...

        Wastewater   Waste water refers to liquid waste and sewage. In urban areas, this type of waste is carried by sewers or underground pipes. The three main sources of waste water are:                  Municipal Waste Water This is the waste water that comes from homes, offices, etc. and is carried by sewers or sewage pipes. The waste water coming from toilets is referred to as black water and waste water coming from kitchens and bathrooms is called grey water.                 Industrial Waste Water This waste is also referred to as industrial effluent. This kind of waste is not mixed with municipal waste water and disposed separately. One of the most incorrect way of disposing this waste is to allow more...

         Forest – A Natural Habitat   Forest is a natural habitat for animals and micro-organisms. Plants, animals and micro-organisms are dependent on each other in a complex way. Plants and organisms in forests are linked to each other by the process called food chain. In food chain, different plants and organisms are linked to each other by the process of eating and being eaten. The food chain is complex. One organism can be eaten by many other organisms and then each of these organisms can be eaten by many others. This creates a complicated mesh called food web. This complex interlinking indicates that if any one type of plant or animal disappears due to some reason from forest, then the survival of other types of organisms will be endangered.         more...

       Forests: Our Lifeline   A forest is a dense growth of trees and various plants, covering a large area of land. It, in fact, is an ecosystem wherein. the community of plants and animals interacting with each other and with the physical environment. However, only about 30% of the world today is covered by forest. Forests are important for maintaining environmental balance and controlling pollution. Forests play the following roles:

• Maintains balance of gases: Forests maintain the balance of carbon dioxide and oxygen, by absorbing carbon dioxide and releasing oxygen.
• Checks pollution: Forests absorb dust and other pollutants. Forests absorb noise and act as barrier against wind.
• Protects soil: The roots of trees bind soil and prevent it from being washed away by rain water or blown by wind. The leaves of tree protect soil from direct rain showers. more...

       Weather Forecasting   Weather forecasting is the process in which the observation of the atmosphere of a particular place, in a particular duration is made. Weather at a particular place depends on its atmospheric pressure, speed of wind and temperature. Observation of weather is observed by automatic weather stations or buoys. Weather satellites give the overall coverage of the earth's atmosphere. Radar gives the information about the weather by radiation or IR (infrared). There after it is analyzed in comparison with previously recorded data. Temperature, humidity, rain gauge are the common parameters of weather. A thermometer is used to measure the temperature. Mercury or alcohol inside it expands on heating. Barometer is used to measure air pressure. An increase in the reading of barometer represents sunny and dry weather while falling reading of barometer represents stormy condition. A rain gauge indicates the more...

         Cyclones   Cyclone is formed naturally over the sea by the heavy and circular, flow of storm. When air of a particular area of upper surface gets heated, it goes upward, thereby creating low pressure area. Air from with high pressure moves to fill the air gap of the low pressure area. If this movement is very fast, it takes the shape of a cyclone. Center of the cyclone is called the eye of the cyclone. The radius of the eye is near about 10 to 30 km. The eye of the cyclone is free from clouds. The strength of the cyclone decreases on moving towards the earth surface.   Look at the following picture of satellite over view of cyclone         more...

       Generation of Wind Current   Wind current is generated by the flow of wind from high pressure area to low pressure area. The speed of wind is called wind current. Major pressure belt are subtropical highs, sub polar lows, polar highs and equatorial low. Subtropical highs lie over ocean and develop in summer. The region between 50° and 70° latitude is known as sub polar low. The region of south and north poles is called polar highs. The lack of sunlight causes the high pressure and low current of wind. Equatorial low, called low region due to the low pressure zone, is developed in the presence of heavy amount of solar radiation. Air gets heated around the equator and goes upwards. High pressure region allows flowing air towards low pressure area.             more...