a must read: THE LAY OF THE LAND: THIN CLIENT OPTIONS. The "thin" comes from the opposite of the acronym "fat" seen on MSFT File Manager when you look at your C Drive: ("Fat" means File application Profile?)
'Ultra-Thin Client - Client/Server' Architecture
Ultra-Thin Client compared to NCs, NetPCs, and Windows Terminals
Introduction
The terminal, once closely associated with mainframe computing, has come into its own. Operator desktops in the mainframe and mini-computer eras were dominated by character mode terminals. Terminals were regarded as a means of providing the operator with an interface to the computer system and its applications. With the introduction of the personal computer, user focus shifted. PCs enabled users to have direct control of applications and functions locally. The need for this control launched a billion dollar computer industry.
Today the tide has shifted. Once again the desktop workstation is being evaluated as a tool where lower cost and functional characteristics are the driving motivation. Surveys conducted in 1992 showed that large installations typically expected to have one time client/server costs of $7,000 per seat with 64% of this amount allocated to hardware and software maintenance. Desktop support, operator training, and PC administration, combined with network administration costs send the total cost of networked PC ownership soaring. As a result the computer industry is searching for more cost effective solutions.
As an example of this changing trend, Microsoft recently announced it has plans to develop client and server software for a sub-$500 Windows terminal that will go head-to-head with network computers. The move is a radical shift for the software giant. Microsoft has traditionally been a staunch proponent of network-ready PCs that store all software and data on a local hard drive ("fat" clients).
Thin-Client Alternatives
Other computer companies have proposed a number of cost effective thin-client computing alternatives to networked PC's. These options can be separated into four basic groups: the NetPC model, the NC (network computer) model the Citrix WinFrame model, and Microsoft's Windows Terminal model.
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NetPC Model
The NetPC computing model is the closest to traditional client-server model in which there are several PCs running off an NT or UNIX server. In this model PC's are replaced with NetPCs (diskless PCs). The client downloads its operating system and applications from a server at startup. The software and data are stored remotely, reducing the cost of service and support of the software. However, processing is done locally and access to remote data uses an Ethernet protocol. Because NetPCs are essentially PCs, they have signifacant hardware costs and the problem of administration still exists.
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NC Computing Model
The NC (network computer) consortium has proposed another option. It has created a completely different architecture that uses Java OS and moves all applications to the Web browser. This option eliminates the need for PC's and uses a server (UNIX or NT) which is hooked up to a series of NC terminals. The terminals download the operating system, browser and software from the server and do Java-based processing locally. They have local memory and processing and receive data using TCP/IP protocol.
The advantages of this model are lower initial hardware and software costs and lower maintenance costs. Also, because most client system software is downloaded at the time of booting up the terminal, changes to the software are easily accomplished. A major disadvantage to the NC computing option is that existing Windows and server applications are not able to run because the architecture must be coded in Java.
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Citrix WinFrame & Prologue WinTimes Model
The Citrix WinFrame or Prologue WinTimes solution brings multi-user capability to the Windows NT environment in a similar manner to how terminals have been supported by Unix. Users run Win32 applications from a central Windows NT host on terminals. The Citrix designers have created ICA (Intelligent Console Architecture) that allows WinFrame clients to communicate with the server with reasonable performance.
This solution lowers cost by providing a single software maintenance point like other thin-client solutions, and enables users to run existing Windows applications like a NetPC. Unlike other thin-client solutions all application processing, with the exception of graphics, occurs on the host, which runs on Citrix's modified Windows NT kernel.
Unfortunately because the solution is reliant on Microsoft's NT Server and Citrix's WinFrame, software licensing costs are high on a cost-per-seat basis. In addition, Microsoft has currently restricted Citrix's and Prologue's license of the Windows NT software to version 3.5.
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Windows Terminal Model
Microsoft's newly proposed idea, the Windows Terminal is yet to be exactly defined. It appears that it will be thin-client or ultra-thin client on which software and data will be received remotely using a yet to be decided protocol and where processing may be remote or local at the terminals.
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The Ultra-Thin Client Alternative
Maxspeed's MaxStations, provide standard Windows software capability at an even more reduced cost than these thin-client alternatives. This solution gives multiple users simultaneous access to a single client PC which can in turn be connected to a server. The OS, applications, and graphics display run on the Windows 95 system and are accessed by the MaxStations using a direct video connection at 32 Megabits per second. The Windows 95 systems can behave as a client to a main server for access to common databases, and a server to the very-thin MaxStation clients simultaneously.
Any software changes on the server or PC are immediately manifested at the user's MaxStation. This technology eliminates the overhead of network traffic to the stations. The PC itself remains fully operable as a local station when access is needed to the diskette or CD-ROM drive.
MaxStations are able to run any browser, Java-enabled applications and standard Windows or UNIX applications. They can act as NC terminals, effectively creating multi-user NC systems. This configuration dramatically reduces cost per seat and maintenance cost to provide Internet access to all users. |
