Learning posts

In star topology all devices or computers are connected to one centralized server. They are connected with server by hub.  Star topology is used in that network where end points are directly reachable from central location. Because each nodes link to the server by different cables. There is no risk of data collisions. Each computer connected to the hub by its own cable segments only a single computer can transmit at a time and every computer on the network wait for message. Thus it is best on broadcasting architecture. a.      Advantages i.                     Devices are attached to server by its own cable, thus break down of cable affects only to that nodes. ii.                   Failure of single node will not affect the rest of the network. iii.                 Central hub can be represent with other having more ports to plugs the nodes. b.      Disadvantages i.                     Failure of central hub will affect whole network. ii.                   More expens

In a bus topology all of the computers in a network are attached to a segment of cable that connects them in a sight line. Each connected computer or peripherals is called terminal or node. Of the network is connected by a terminating resistor which prevents single interference.           In a bus topologies the nodes are of passive participate i.e. listing on the line and waiting for message address to them. This type of network can transmit to any other node whenever it wants. Transmit is limited to one computer at a time thus at one time the computer is master and all others are waiting message to read. Terminator was used in end of cable. a.       Advantages i.                     It is simple reliable and easy to use. ii.                   Single backbone cable is required to connects all nodes, thus is cheaper. iii.                 Other computers are can easily added and network can be extended. iv.                  A repeated can also be used in extended cable.

A network topology is the arrangement of the computers cable and other components on a network. The major goal of network topology is to find out the most economical and efficient way to connect all the users to the network resources while providing adequate capacity to handle users demand, maintain system reliability and decrease the delay.    Topology is the map of physical network. The type of topology we use defect the type and capabilities network hardware’s its management and possibilities for future expansion. There are many types of network topology, some of these are:   Bus Topology Star Topology Mesh Topology   Ring Topology Tree Topology

The computer system has two types of memories in general; one is called volatile and the other is non-volatile. The word volatile is used for these devices because of their temporary or permanent data storage capacities. Memory means the data storage capacity in a device. Like we have brain a part of it is volatile and a part of it is non-volatile, how? This will be easily understood after reading the characteristics of the two memories of the computer system. Volatile Memory A device or a memory device in the computer that needs current to work and keeps the record or data in it is called volatile memory. As its name suggests it need current or electricity to work and to keep the record in it once the current is cut down the data disappears. The most common example of volatile memory is the RAM (random access memory) of the computer. The operating system loads in it and once the power is off, everything erases form RAM that’s why we need to start our system and wait for loading of th

Buffer   It is an area of computer’s memory or devices memory for holding data during data transfer. Normally I/O devices have low speed than processor. This speed adjusted by having temporary data storage in a memory typically called buffer. While the device is in operation data transfer can take place in buffer. The process of holding data temporarily during I/O operation is called buffering. Because of buffering , I/O channels place data in buffer and the processor or I/O devices can access data from the buffer.        Cache Memory The cache memory is placed in between CPU and main memory. It is a semiconductor memory. It consists of static RAMs. It is a special and very high speed memory that is used to increase the speed of processing by making current program and the data available to the CPU at a rapid rate. Cash memory holds the frequently used instruction and data so that it can provide CPU at a faster rate. It is fabricated along with the CPU so works same as the sp

        Computer is used in almost every field in developed countries. Industrial advancement, agriculture, defense, education, commerce and business, medicine, tourism, banking etc., are the core areas where computer science is utilized. Today man can communicate from one part of the world to the other part easily, which is an example of the advancement of computer science. Within a minute, man can communicate through telephone, Telex, Fax & TV from one part of the world to the other. Computer helped in banking network also. Your deposited money in a bank of foreign country can be withdrawn using ATM(Asynchronous Transfer Mode) card or Master Card from the other country, and your hand-prints can be sent to any part of the world at great speed.                   Computer has its application not only in manufacturing, medical research, education and defense,but it is also used in small business offices to handle day-to-day work easily and efficiently. Due to growing importance and

We know that a vehicle for communication is known as medium. It can be speech or still picture. The vehicles of communication that use some combination of speech, text, still graphics, animation, moving pictures and sound are known as Multimedia. From this definition we can say that TV show is multimedia experience. A multimedia has a characteristic feature of interactive. In interactive multimedia, users can choose their own path through the presentation. The Interactive multimedia has helped to make World Wide Web (WWW) popular. Most web pages include graphics along with the text and may of them offer animations, videos and sounds. 

The C language was developed at AT & T (American Telegraph & Telephone)  Bell Laboratories in the early 1972's by a system programmer named Dennis Ritchie. It was written originally for programming under an operating system called UNIX which itself was later rewritten almost entirely in C. Its name encrypted as C, derives from the fact that it is based on an earlier version written by Ken Thompson, another Bell laboratories system engineer. He adapted it from a language that was known by the initials BCPL (Basic Combined Programming Language). Thompson derived his programming language name as B, the first of the initials BCPL. When the language was modified and improved to its present state, the second letter of BCPL, C was given to it. The C language is often described as a middle level language. It permits programs to be written in much the same style as that of most of high-level programming language. It also interacts with the inner workings of the computer. The Americ

               All organizations have several types of information system. At any point in time, varying degree of these information systems may be computer based. For example, an organization's payroll information system may be computer based, but its strategics planning information system maybe processed manually. As time passes, organizational processes change. The organization's information system must change in response to the changing needs of the organization. When this occurs, management usually initiates some form of a system development life cycle(SDLC) to address the problem.

When a page is accessed, if the valid/invalid bit is set to valid, then the page is simply accessed in main memory via the logical address entry in the table. If the page is not contained in physical memory, then a page fault is generated. This causes the program to try and load the page into memory. The system first checks if the requested address is valid. If not, then the process is terminated. If the address is valid, then the system checks for free frames. If a free frame is found, then the system loads the requested data from the disk and places it in the free frame. The valid/invalid bit is set to valid in the paging table, the logical address is set to the previously free frame, and the program can continue executing. If no free frames are present, then the system must swap out a currently used frame and place the requested data in the frame. The system, an algorithm such as LRU, MRU, etc. to determine which page to swap out. The system swaps out the old page, loads in the new