Comparing Host-Based and Windows 2000-Based Terminal Services
In some ways, Terminal Services are analogous to older, centralized host or mainframe, environments. In the centralized host architecture, dumb terminals provide a simple, character-oriented conduit between the user and the host. Users can log on, run programs, read/write shared files, direct output to shared printers, and access shared databases. Furthermore, each terminal session functions independently from other terminal sessions because the arbitration between shared resources is performed deep inside the host operating system.
Terminal Services differ somewhat from the centralized host architecture. The primary difference is the graphical nature of the Windows 2000 Server operating system environment. Host environments have traditionally been character-oriented, requiring only a small amount of traffic (ASCII characters) to travel the communication lines between the host and the terminal or terminal emulator. With Terminal Services, all of the graphical screen output and related input/output (for example, from a mouse or keyboard) must flow between the desktop client (that is, the Windows-based Terminal or terminal emulator running on a computer) and the Windows 2000 Server running Terminal Services. This means for highly graphical and animated applications, a lot of information must travel over the network to the client device. Fortunately, the display protocol that operates between the Terminal Services client and the server optimizes this transmission and is completely transparent to the application developer. Additional information on the Microsoft Remote Desktop Protocol (RDP), the display protocol used by Terminal Services, can be found at the Microsoft Windows 2000 Web site.
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