3 lessons you must know about computer

<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnCkLxozjBNKCpDvdpQSOVu_IVTyt-D91NE60pUWkEPYkRTQ1WWCIon05C74aBSdyuyHgtgl2Th2MRkf5Sc7t4EkOvw5r_L0y_w7q0jO-Pzl6AiWWRmot7bv297KDbSJeRwGccjouNz37K/s1600/computer-lesson.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnCkLxozjBNKCpDvdpQSOVu_IVTyt-D91NE60pUWkEPYkRTQ1WWCIon05C74aBSdyuyHgtgl2Th2MRkf5Sc7t4EkOvw5r_L0y_w7q0jO-Pzl6AiWWRmot7bv297KDbSJeRwGccjouNz37K/s1600/computer-lesson.gif" /></a></div><br /> Computer is a very important part of our daily life now a days. So we all need to know some basic knowledge about computer. Computer is used to called calculator machine but now it can reduce a lot of human effort and work all alone and do multiple task without any help and in a very short time. As before we are going to start to post more computer lessons and basics fast of all you need to learn how a computer works. These are the basic three examples listed below how a computer works ?<br /> <b><br /> 1.Data representation<br /> 2.Data processing</b><br /> <b>3.Components affecting speed</b><br /> <br /> <span style="font-size: large;">How computer represent data ?</span><br /> <br /> <b>Number systems </b><br /> - A manner of counting<br /> - Several different number systems exist<br /> Decimal number system<br /> - Used by humans to count<br /> - Contains ten distinct digits<br /> Digits combine to make larger numbers.<br /> <br /> <b>Binary number system</b><br /> - Used by computers to count<br /> - Two distinct digits , 0 and 1<br /> - 0 and 1 combine to make numbers<br /> <br /> <b>Bits and bytes</b><br /> - Binary numbers are made of bits<br /> - Bit represents a switch<br /> - A byte is 8 bits<br /> - Byte represents one character<br /> <br /> <b>Text Codes</b><br /> - Converts letters into binary<br /> - Standard codes necessary for data transfer <br /> - ASCII<br />   - American English symbols<br /> - Extended ASCII<br />   - Graphics and other symbols<br /> - Unicode <br />   - All languages on the planet<br /> <br /> <span style="font-size: large;"><b>How a computer Process data ?</b></span><br /> <br /> <b>The CPU</b><br /> - Central Processing Unit<br /> - Brain of computer<br /> - Control unit<br />   - controls resources in computer<br /> - Arithmetic logic unit<br />   - simple math operations<br />   - registers<br /> <br /> <b>Machine cycles </b><br /> - Steps by CPU to process data<br /> - Instruction cycle<br />   - CPU gets the instruction<br /> - Execution cycle<br />   - CPU performs the instruction<br /> - Multitasking allows multiple instructions<br /> <br /> <b>Memory </b><br /> - Stores open programs and data<br /> - Small chips on the motherborad<br /> - More memory makes a computer faster<br /> <br /> <b>Nonvolatile memory</b><br /> - Holds data when power is off<br /> - Read only memory (ROM)<br /> - Basic Input Output System (BIOS)<br /> - Power On Self Test (POST)<br /> <br /> <b>Flash Memory </b><br /> - Data is stored using physical switches<br /> - Special form of nonvolatile memory<br /> - Camera cards , USB key chains<br /> <br /> <b>Volatile memory</b><br /> - Requires power to hold data<br /> - Random Access Memory (RAM)<br /> - Data in RAM has an address<br /> - CPU reads data using the address<br /> - CPU can read any address<br /> <br /> <span style="font-size: large;"><b>Components Affecting Speed</b></span><br /> <br /> <b>Registers</b><br /> - Numbers of bits processor can handle<br /> - Larger indicates more powerful computer<br /> - Increase by purchasing new CPU<br /> <br /> <b>Virtual RAM </b><br /> - Computer is out of actual RAM<br /> - File that emulates RAM<br /> - Computer swaps data to virtual RAM<br />   - Least recently used data is moved<br /> <br /> <b>The computer internal clock</b><br /> - Quartz crystal<br /> - Every tick causes a cycle<br /> - Speeds measured in Hertz (HZ)<br />   - Modern machines use Giga Hertz (GHz)<br /> <br /> <b>The bus</b><br /> - Electronic pathway between components<br /> - System bus connects CPU and RAM<br /> - Bus width is measured in bits<br /> - Speed is tied to the clock<br /> <br /> <b>Peripheral control interface (PCI)</b><br /> - Connects modems and sound cards<br /> - Found in most modern computers<br /> <br /> <b>External bus standards </b><br /> - Industry Standard Architecture (ISA)<br /> - Local bus<br /> - Penpheral control interface (PCI)<br /> - Accelerated graphics port (AGP)<br /> - Universal serial bus (USB)<br /> - IEEE 1394 (fireWire)<br /> - PC Card<br /> <br /> <b>Accelerated Graphics Port (AGP)</b><br /> - Connects video card to motherboard<br /> - extremely fast bus<br /> - Found in all modern computers<br /> <br /> <b>Universal Serial Bus (USB) </b><br /> - Connects external devices<br /> - Hot swappable [ device can be attached or detached without reboot]<br /> - Allows up to 127 devices<br /> - Cameras , printers and scanners , mouse , keyboard and others.<br /> <br /> <b>PC Card </b><br /> - Used on laptops<br /> - Hot swappable<br /> - Devices are the size of a credit card<br /> <br /> <b>Cache Memory</b><br /> - Very fast memory<br /> - Holds common or recently used data<br /> - Speeds up computer processing<br /> - Most computers have several caches<br /> - L1 holds recently used data<br /> - L2 holds upcoming data<br /> - L3 holds possible upcoming data

3 lessons you must know about computer

Computer is a very important part of our daily life now a days. So we all need to know some basic knowledge about computer. Computer is use...

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What is an information system ?

<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCGgXDiBe2Z4wlk6vGOdqZRUeRm3yp4QuPwb2-5xKUvF9yqpxsGLIYboQwEhBdDo5g0N5wq9RiQw3w1VQPCenWyF4SYrBfLamaEb-HnBHEVy2AuP6izMabXhBRQuaO6j8dETU7THB9ih3N/s1600/information-system.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="142" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCGgXDiBe2Z4wlk6vGOdqZRUeRm3yp4QuPwb2-5xKUvF9yqpxsGLIYboQwEhBdDo5g0N5wq9RiQw3w1VQPCenWyF4SYrBfLamaEb-HnBHEVy2AuP6izMabXhBRQuaO6j8dETU7THB9ih3N/s320/information-system.jpg" width="320" /></a></div><br /> <b>Data :</b> we call raw facts and figures data. Facts and figures often have little meaning until they are sorted or until we calculate something from them. This sorting or calculation is called data processing. When data is processed , it provides information. Data > processed > information.<br /> <br /> <b>Information :</b> Information is the meaning we attach to the data. For instance , a red traffic light is a form of data. The meaning we attach to this data is the information. Somethings data can give rise to ambiguous information.If you are driving a car and a car traveling in the opposite direction flashes its light at you , what does it mean ? it could just mean that a friend has spotted you and is saying hello. It could also mean that there is an accident further up the road. The information that may be obtained from data depends on the way that the data is interpreted and the context in which it is used.<br /> Data is often meaningless. For instance consider the number 131212. We could interpret this in any number of ways. for example :<br /> 1. Your driving liecence number.<br /> 2. the date 13/12/2012<br /> 3. the number of cars going down a certain road in week.<br /> <br /> The tree stages odd doing task<br /> All task can be broken down into three stages : input, process and output. Like input > Process > Output<br /> <br /> <b>Manual information system</b><br /> We are all used to dealing with some sort of manual information system. A telephone directory is an example. There may be several hundred thousand entires, but if we know the surename and address of the person we are trying to contact, we can find the number provided that it is in the directory. Manual information systems have many disadvantages. lets look at an example. Suppose you have a friend whose phone number and surename you know but whose address you need to find. You do not know their parent's initial and their surename is, unfortunately, Rahman. You could find the address by taking the following steps:<br /> 1. Look up the section for Rahman.<br /> 2. Start from the beginning and work through the phone numbers, looking for the area code look for 1207 and see if the rest of the number coincides.<br /> 3. Once the phone number has been found you can read off the address.<br /> <br /> An even worse problem might be if you had phone number of a person scribbled down on a piece of paper and you wanted to find out who you were ringing first. The telephone directory is ordered alphabetically according to surename and not in numerical order.According to the telephone number, so to find the number would prove an immense and time consuming task.<br /> <br /> <b>Computerised information system</b><br /> Computerised information systems are much more flexible than manual ones and a lot faster. With computerised system you could type in a phone number and if the number was stored in the system the name and the address could be provided immediately to you.<br /> <br /> Examples of computerised information system<br /> <br /> <b>The Driver Vehicle Licensing Authority</b><br /> The driver vehicle licensing authority (DVLA) keeps a huge collection of information concerning every driver and every vehicle in the country. Such a huge collection of data is called a database. Summarised details of this database are passed to the Police National Computer (PNG).<br /> Suppose there has been a hit and run accident and a witness is able to remember part of the registration number like _294_N ___.<br /> Imagine trying to search through the thousands of car registration having those letters or numbers in them. Even a computer can take some time doing these sorts of searches. Even rose , what would happen if we only knew that the car was a Audi r8 with partial registration L__N__. this type of situation happens all the time when the police are trying to trace cars. Computerised information systems are one of the main weapons in the fight against crime.<br /> <br /> <b>A computerised school management system</b><br /> Consider your school or college. In the secretaries office there will be a computer containing all information on all the students in the school or college. What are the requirements of a school infromation system ? <br /> Here are some of the taks that the system would need to deal with.<br /> 1. The system must record the attendance details twice a day for all the students. It must be able to identify students have poor attendance records so that they may be investigated.<br /> 2. It must list students personal details. This would include such things as name , address , mobile number , telephone number, date of birth , name of the parents or guardian , day time contact numbers, sex , religion , medical problems, form. form teacher's name, mode of travel to school, whether students stay for school dinners and so on.<br /> 3. It must be easy to produce the various lists such as lists of students for registration groups, teaching groups, parents evenings and school trips.<br /> 4. It must be possible to get infromation easily from the system so that letters may be generated and send to certain students.<br /> 5. The system must be able to cope with the administration for examination entries.<br /> 6. It must cope with all the financial aspects of running a school.<br /> 7. The system should be able to help organise a timetable, making the best use of the teachers and the rooms.<br /> <br /> As you can see from the above list, a lot of work goes on behind the scenses in school.<br /> <br /> <b>Advantages of a computerised information management system</b><br /> 1. You dont need lots of filing cabinets to hold all the students files and other forms.A single computer can store all the information needed. <br /> 2. Terminals can be used, So that many people can access the infromation in differet places at the same time. Whenever data is updated it is instally available to all the people using the system.<br /> 3. There is no duplication of information. The students details need only be entered once and then used for different tasks. it is possible to produce year lists, class lists, option lists etc. Using the data from the students files.<br /> 4. The system can be used in conjunction with a word processor to product mail shots to students home.<br /> 5. some information can be transferred to the system without using the keyboard.<br /> <br /> <b>Disadvantages of a computerised information management system</b><br /> 1. Everything depends on the computer system. If there is a power failure occurs, or if the system breaks down then an alternative system will need to be used.<br /> 2. To use the system, the staff will need to be trained. When staff leave their expertise will be lost and new staff will need to be trained.<br /> 3. Security will need to be provided to protect personal students and staffs information from prying eyes.<br /> Students personal details need only be recorded once on the system. Even a photograph can be put into it.The system is easy for everyone to use and can use the Windows style of menus.All aspects of the school administration can be dealt with by the system, from running the school library to recording students option choices. The form is used to record students option choices. Each option has different barcode, which can be stuck to the form. The details can be read by using optical character reader.<br /> <br /> The schools information management system enables the head teacher of the school to run the school as effiently as possible for benefit of all the students. Taks that would have taken a long time now can be done quickly.

What is an information system ?

Data : we call raw facts and figures data. Facts and figures often have little meaning until they are sorted or until we calculate somethi...

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