Basics of networks
Computer network – a set of interconnected stand-alone computers to work together on information, computer and other tasks.
Two computers are said to be related if they can share information. Requirement of autonomy is used here to avoid using distributed system (one computer can manage the work force others). System with one control unit and not more managed network. In a distributed system, there are numerous stand-alone personal computers, operating transparently (invisible to other users). Users of the system, setting the team, do not know about the existence of multiple processes running the command. In computer networks, the user must explicitly create a machine and explicitly delete the job.
The simplest form of an ad-hoc network that links personal computers and allows end users to share drives, printers, files.
More advanced network other than end-user computers (workstations) include a dedicated computer servers. The server is a computer that runs a network of service functions other computers in the network.
1.1. Computer Networks
The need to use computer networks:
1) Sale of air and rail / train tickets;
2) Access to information of computer data banks;
3) Exchange of information between the slave. a teacher, and a servant. places students.
1. In organizations:
1) Sharing of resources, cat provide access to programs that are given to any user, regardless of the physical. the location of the resource and the user;
2) Ensuring high reliability through the use of alternative sources of information;
3) Ability to save money;
4) Ability to scalability;
5) Ability to operational communications between remote employees.
1) Access to remote information
3) Interactive video games, TV;
1.2. Server types. ARCHITECTURE ” client-server ”
1) Print Server – printers connected to the network via a dedicated node processing print jobs;
2) The database server – a shared database;
3) File Server – a data warehouse;
4) Communication Server – controls access to remote resources, provides a link to the global compute. network;
5) Application Server – made special computational tasks (graphics processing);
6) Web server – Provides access to web pages.
Very popular today and are extremely promising technology for information processing in the network called. ” client-server ”.
The functions of the ” customer ” includes:
1) Provide the user interface, based on certain production duties and powers;
2) The form requests to the server;
3) Analysis of server responses to requests and presenting them to the user.
The main function of the server-specific implementation actions at the request of the client (for example, the complex mathematical problem, search the database, a client connection with another client, etc.), while the server itself does not have any interaction with the client. If the server to which the client is asked, unable to solve the problem of lack of resources, then ideally he finds another, more powerful server and transfers the problem to him, becoming, in turn, the customer, but not without informing the for primary client.