2. Use of networks

Network access is a fully-fledged function of operating systems. These accesses are independent of the type of local, metropolitan or public network. In particular, Unix systems, followed by Novell and Microsoft, have popularized the TCP/IP protocol stack and related services. TCP/IP has become the universal protocol for computer networks. For several years now, Microsoft, Linux, Solaris and BSD operating systems have been integrating a TCP/IP stack and TCP/IP services that are widely used:

• virtual terminal (telnet): this service takes over the original function of computer networks. It enables you to connect to a remote system and execute commands. For Unix systems, programs such as rlogin or rsh are essentially equivalent;

• file transfer (ftp – file transfert protocol ): this service enables files to be...