Centralized administration and thin clients are issues of priority today for many IT departments in organizations around the world. The need for thin clients is being driven by the desire to lower device and management costs as well as adequately meet new application and user requirements, such as kiosk-type applications in a hotel room or airport.
Terminal Services offers the Windows experience on a diverse set of desktop hardware, providing a complete, Windows-based thin-client solution. It simultaneously provides all of the benefits of distributed computing and centralized administration, as in a mainframe model, to Windows customers. Specifically, Terminal Services delivers the Windows NT operating system experience to desktops that cannot currently run the 32-bit Windows operating system. Examples of such desktops include dedicated thin client devices, personal computers running 16-bit versions of the Windows operating system, Windows CE-based devices, or UNIX and Apple Macintosh based machines (available through an add-on package).
Terminal Services provides clients access to 32-bit Windows-based applications running entirely on the server. Multiple client sessions are supported at the server. The server manages all computing resources for each client connected to the server and provides all active users with their own operating environment. All keystrokes and mouse clicks sent by the remote client are received and processed by the server. All display output for both the operating system and applications are sent to the appropriate client. After logging on, users can access all of their authorized network resources and can run applications made available to them on the server. Because Terminal Services supports virtually every application supported by Windows NT, users potentially have access to virtually all major 16- and 32-bit Windows-based applications via a thin client environment.
If there is one area in which Solaris 7 shines it is in the availability of thin clients. The multi-user environment is where Solaris and other UNIX variants were originally developed. Therefore, it is no surprise that a wealth of tools and third-party applications can take advantage of the multi-user aspects of the server via various types of thin clients.
The most common thin client implementation is probably that of the X terminal. This is a device (specialized terminal, PC with appropriate software, etc.) that runs an X Windows application that allows it to remotely execute applications on the server with a local console session. This is a very mature technology and enjoys wide support from the vendor (both software and hardware) community.
Though not as popular, various Java-based solutions, ranging from Java-only terminals to Java applications running on a PC, offer the same type of support available from an X Windows terminal in running remote applications. They also add the ability to locally execute Java applications.
While not specifically a thin client solution, the Solstice AutoClient application allows systems to remotely boot from a Solaris 7 server. All system files and user data are stored on the server and only cached on the client machine while the session is active. These clients can run an X Windows session while maintaining the full processing power of the local workstation. They also give the system administrator the benefits of centralized administration available to the other thin client solutions. Therefore, it is a very popular alternative in the Solaris 7 environment. As of version 3.0, however Solstice AutoClient is no longer included with Easy Access Server. You must obtain and install this component separately from the operating system.
If there is a single weak spot in the thin client support available for Solaris 7, it is the lack of an integrated management solution for the thin clients.
Windows NT Server 4.0 Implementation Details
The Windows NT Server 4.0 Terminal Server Edition is a separate edition of Windows NT Server 4.0 with the Terminal Services feature integrated into the operating system.
The Terminal Services feature extends Windows NT Server 4.0 to provide true, multi-user support. The operating system has added two new management tools – Client Connection Manager and License Manager – to help administer Terminal Services. Client support is provided for 16-bit and 32-bit Windows-based machines. Additional client-support for Macintosh or UNIX-based clients is obtainable through Citrix MetaFrame. Windows-capable terminals, such as those available from Tektronix, NCD, Cruise Technologies, Boundless Technologies, Wyse, or Neoware connect to a machine running Windows NT Server 4.0 Terminal Server Edition as-is – no additional client software is required.
The Client Connection Manger utility, available as part of the Terminal Services Client software, allows administrators and end users to setup predefined connections to one or several servers for single application or full desktop access. It creates an icon that can be used for single-click connectivity to one or more Terminal Servers. This provides the necessary support for administrators to provide a single line-of-business application across an entire enterprise by simply creating an icon, saving it, and then distributing it using the client software to all desktops.
The License Manager tool assists system administrators and purchasing officers in keeping track of client connectivity for license monitoring and tracking purposes. It is similar to the licensing tools provided as part of Windows NT Server 4.0, except that it has been modified to track per desktop. Licensing continues to be honor-based as has always been the policy with Windows NT; the tool has been provided merely to aid administrators.
Application compatibility has been a focus for Terminal Services throughout the development process. Almost all applications that will run in a Windows NT 4.0 environment will run on Terminal Services. Microsoft has performed extensive testing on a wide range of applications and has provided setup scripts for all popular business and productivity applications to help address any multi-user issues that may arise.
Windows 2000 Server Implementation Details
Terminal Services have been fully integrated into the Windows 2000 Server as an optionally installable service and is no longer shipped as a separate product. Every feature in the Windows NT Server 4.0 Terminal Server Edition is present as part of the Terminal Services feature of Windows 2000 Server. However, the Terminal Services implementation in Windows 2000 Server has been enhanced to support Windows 2000-based applications and the new features in the Windows 2000 environment. This is in addition to continuing to provide full support for all existing 16- and 32-bit Windows-based applications.
Also new in Windows 2000 Server is Distributed File System (DFS) support. Terminal Services clients can connect to a DFS share and DFS shares can be hosted from machines running on Terminal Services. A new MMC based utility facilitates the creation and distribution of client software for Terminal Services. Additionally, several new features are under development for inclusion in the Windows 2000 Server edition of Terminal Services including an RDP Web Client (via an ActiveX control), load balancing, shadowing, public Terminal Services APIs, support for all OLE/DCOM activation modes, persistent caching, and redirection of COM, printing, clipboard, and audio.
Where thin client support is a priority, Windows NT Server 4.0 Terminal Server Edition and Windows 2000 Server provide a thin client solution that runs standard, line-of-business Windows-based applications such as Microsoft Office. In Windows 2000, terminal clients can connect to and host DFS shares.
Solaris 7 provides a wealth of thin client solutions. These solutions range from the traditional UNIX serial terminal-based connection option through Java clients. The most widely used thin client solution is X Terminal. X Terminal is a very mature technology and enjoys wide support from the vendor community. Beyond a strict thin client solution, Solaris 7 also supports Solstice AutoClient. With AutoClient workstations, all operating system files and services are loaded from a server.