computer teacher

 Cloud Services A better way to understand the cloud is to interpret everything as a service. A “service” corresponds to any facility provided by the cloud.  There are three standard models to categorize different computing services delivered through cloud as shown in Figure 3.12.  These are Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Infrastructure as a Service (IaaS) The IaaS providers can offer different kinds of computing infrastructure, such as servers, virtual machines (VM), storage and backup facility, network components, operating systems or any other hardware or software.  Using IaaS from the cloud, a user can use the hardware infrastructure located at a remote location to configure, deploy and execute any software application on that cloud infrastructure.  They can outsource the hardware and software on a demand basis and pay as per the usage, thereby they can save the cost o...

 Grid Computing A grid is a computer network of geographically dispersed and heterogeneous computational resources as shown in Figure 3.13.  Unlike cloud, whose primary focus is to provide services, a grid is more application specific and creates a sense of a virtual supercomputer with an enormous processing power and storage.  The constituent resources are called nodes.  These different nodes temporarily come together to solve a single large task and to reach a common goal. Nowadays, countless computational nodes ranging from hand-held mobile devices to personal computers and workstations are connected to LAN or Internet. Therefore, it is economically feasible to reuse or utilise their resources like memory as well as processing power.   The grid provides an opportunity to solve computationally intense scientific and research problems without actually procuring a costly hardware. Grid can be of two types— (i) Data grid, used to manage larg...

 Blockchain technology  Traditionally, we perform digital transactions by storing data in a centralized database and the transactions performed are updated one by one on the database. That is how the ticket booking websites or banks operate. However, since all the data are stored on a central location, there are chances of data being hacked or lost. The blockchain technology works on the concept of decentralized and shared database where each computer has a copy of the database.  A block can be thought as a secured chunk of data or valid transaction. Each block has some data called its header, which is visible to every other node, while only the owner has access to the private data of the block. Such blocks form a chain called blockchain as shown in Figure 3.14. We can define blockchain as a system that allows a group of connected computers to maintain a single updated and secure ledger. Each computer or node that participates in the blockchain receives...

COMPUTER MALWARE malware is used to describe any malicious program on a computer or mobile device installed without the consent of the user and can cause a number of annoying effects, such as  the hard disk has more files than it had earlier;  computer tends to run slower than normal;  computer starts rebooting unexpectedly; applications take a long time to load and may not work properly; computer often hangs and stops responding and tends to restart on its own; the keyboard keys seems to lock and at times you will see distorted menus and dialog boxes on the screen. A malware may enter your computer system through the internet or through an infected pen drive, a DVD, a CD, while you are working on a computer, for example: sharing files - photos, audio or video visiting malicious website opening a spam email or an email attachment or link in the mail downloading free games, media player and other system utilities installing mainstream software applications without reading ...

DBMS APPLICATION In today's competitive world, application of DBMS is not just limited to a a bank, but it pays a vital role in stock exchange, Railway and airline ticket Reservation, schools & the list goes on and on. Not only at this level, database and database management system is required at all levels and areas of an organization.  Also DBMS is required, if you want to - * build computerized business  applications. * create business applications that operate on multiple locations * conduct business on the internet * Enable customers to place orders using the web. application of DBMS in an organization :  * marketing professional to analyze sales data. * Human Resource managers to evaluate employees. * operation manager to track and improve quality. * Accountant ti integrate data across  the enterprise. * Financial analyst to analyze firm's performance. some specific applications of DBMS are as follows :  *banking : For customer ...

               DATA INDEPENDENCE Any software has mainly two parts, first is the database and second is the application or program which accesses and uses the database. First the database is designed and then the application program are written for it, which heavily depends on database design. sometimes, after the application program has been written there is need to change the storage structure or database design. data independence is all about, the ability to modify a schema definition (i.e. storage structure) in one level without affecting a schema definition in the next higher level.  There are two levels of data independence. 1. physical data independence : physical data independence is the ability to modify the physical schema without causing application programs to be written. 2.logical data independence : logical data independence is the ability to modify logical schema without causing application programs to be rewritten. ...