Computers and Software 4

TCP / IP protocol makes it possible to transmit information, but it used a variety of network services in different ways to manage this information. Internet has not solved the problem of storing and ordering information, but solved the problem of transmission, making it possible to get it anytime, anywhere. Since Network (hereinafter referred to as network-with a capital-would mean the Internet) is decentralized, then turn off, even a large part of the computers will not affect its functionality. According to analysts, in 1995 the number of fully networked computers accounted for about 7 million and continues to grow rapidly. By the same estimates, at the beginning of the next century the network may be as accessible as the telephone or television today.

In the web there are a large number of services. We will continue to be interested in the WWW or simply Web (Word-Wide Web-the World Wide Web). This is the most popular web service and convenient way to work with information. Today, there are at least 30 thousand servers, WWW. It is through the WWW network is growing so rapidly. Using simple language descriptions can be Hypermedia documents for subsequent publication in the web (I mean a hypermedia document that can contain all kinds of information - from simple text to multimedia clips). To see the contents of the document as it imagines the author must have client-side viewer browser. The most popular today, Netscape Navigator, supports many extensions to HTML (Hyper Text Markup Language-Hypertext Markup Language documents - namely with the help of formalized information in WWW). Further, under words the browser or viewer I mean is this program, although not excluded that some other program is able to display all the way it was intended.

Now a little information about the technology "client-server". It has been known for quite a long time, but had often been used in large scale enterprise networks. Today, with the development of Internet, this technology is increasingly attracting the eyes of software developers. The world has accumulated a wealth of information on various issues. Most of this information is stored in databases (DB). To publish it in the web had to export the database in HTML-documents, which required costly and complicated the search for information. Today there is wide experience of similar works. Almost every web user is often faced with such a database. For example, the main thing in the popular search engine Yahoo (address-http:: \ \ www.yahoo.com) - a query to a database of WWW-server keywords. A server-list of hypertext links found in web pages that contain the necessary information. It is today the problem of Web-interface to the database as never before.
Internet - a global computer network covering the whole world. Today the Internet has 15 million subscribers in more than 150 countries. Monthly size of the network increases by 7-10%. Internet forms the core, providing us various information networks belonging to various institutions throughout the world, with one another.
Previously the network was used exclusively as a medium for file transfer and e-mails, now solve more complex problems of distributed access to resources. About two years ago created a shell that supports a network search function and access to distributed information resources, electronic archives.

Internet, which served as a purely research and academic groups, whose interests extended until access to supercomputers, is becoming increasingly popular in the business world.

Companies tempt fast, cheap global communication, convenience to carry out joint operations, the available programs, a unique database on the Internet. They see the global network as a complement to their own local networks.
With a low cost of services (often only a fixed monthly fee or telephone line used), users can gain access to the commercial and noncommercial information services USA, Canada, Australia and many European countries. The archives of free access to the Internet can find information on almost all spheres of human activity, from new scientific discoveries to the weather forecast for tomorrow.
Besides Internet provides unique opportunities for cheap, reliable and confidential global communications around the world. This is very convenient for companies with branches all over the world, transnational corporations and governance structures. Typically, the use of Internet infrastructure for international communication is considerably cheaper than direct computer connection via a satellite channel or via telephone.

E-mail - the most common service on the Internet. Currently your address by e-mail are approximately 20 million people. Sending emails is considerably cheaper than sending regular letters. Besides the message, sent by e-mail reaches the recipient for several hours, while an ordinary letter can reach the recipient several days or even weeks.

Currently, Internet is experiencing the period of recovery, thanks largely to strong support from European governments and the United States. Every year in the United States allocated about 1.2 million dollars to build new network infrastructure. Research in network communications funded by the Governments of Great Britain, Sweden, Finland and Germany.

However, public money - only a small part of the inflows, as more visibly "kommertsizatsiya" network (it is expected that 80-90% of the funds will come from the private sector).

Community reshivshie connect your computer to the network should pay special attention to the protection of information. Strict requirements for protection of information related to the fact that the connected computer is accessible from anywhere in the network, and therefore a much more exposed to defeat viruses and nesanktsioirovannomu access.

So non-compliance regime for the protection from unauthorized access could lead to information leaks, and failure modes of protection against viruses may lead to failure of critical systems and destroy the results of many days of work.
Computers operating in multitasking operating systems (such as Unix, VMS) enough to become infected with viruses, but they should be very carefully protected from unauthorized access. In this regard, users are multitasking operating systems must fulfill the following requirements.

Each user must have their own individual login to the Unix-server and a password.
Installed for users' passwords are not required to report to others.
Changing the password the user must perform at least once per quarter, as well as in all cases of leakage of information about the password.
Administrators and users of file-servers NetWare LANs must also follow the above requirements within their LAN. This is due to the fact that if a file server connected to the network, loaded utility Iptuunel, then the file server also becomes accessible from anywhere in the network.

PC working in odnozadachnyh operating systems (such as MS-DOS), suitably protected from unauthorized access (by virtue of their odnozadachnosti), but they should be particularly careful to protect from the virus.

To protect against viruses is recommended to use security software (such as aidstest), as well as hardware and software (such as Sheriff).