5.11. Organization of work in a hierarchical network

Hierarchical networks have one or more servers. They contain information that is simultaneously used by different users. There are file servers, database servers, print servers, and mail servers.

The file server contains shared files and cumulatively used programs. At workstations there is only a small part of these programs that require little resources. Programs that allow this mode of operation are called programs that can be installed on the network.

The database server hosts a database, for example, ConsultantPlus, Garant, Bank Accounts, etc. The database on the server can be replenished from different workstations or provide information on requests from the workstation. In this case, there are three fundamentally different modes of processing requests from a workstation or editing records in the database:

1) Database records are sequentially sent from the server to the workstation, on which the filtering of records itself and the selection of necessary ones take place. In this case, the server requirements are reduced, but the load on the network channels and the computing power requirements of the workstations increase;

2) the server selects the required records from the database and sends them to the workstation. This reduces the load on the network and decreases the level of requirements for workstations. In this case, the requirements for server processing power increase dramatically. This method is the best and is implemented by special tools for working with modern network databases;

3) “drain-spill” mode is used when the server, workstation or network is low. It is used to enter new records or edit them if the database record can change no more than once a day.

To create a print server , a sufficiently powerful printer is connected to a low-power computer that is used to print information simultaneously from several workstations.

The mail server is designed to store information sent and received both via the local network and externally via a modem. In this case, the user can view the information that came for him at any convenient time or send his own mail server.

For each user on the server hard disk there are three areas:

1) personal, accessible only to the user with all rights, for example, creating folders and files in it, editing and applying files, deleting them. Other users are not given access to “foreign private areas”, they do not see them using the file system, since personal areas are used to store confidential user information;

2) General, to which all users of the network with simultaneous read and write access simultaneously have simultaneous access. This area is used to exchange information between different network users or workstations. To accomplish this, information from the user's personal area or from the local disk of the workstation is recorded in a common area. From this area, another user copies it to his personal area or to a local disk of another PC;

3) reading area in which the user can only read information.

In order to gain access to the personal area on the server, the user must complete the procedures for logging into the network or registering with the network. The procedure for entering the network is carried out after turning on or restarting the computer.