MultiWin Gets Its Audition

NetPC was just the overture; Citrix's MultiWin will be the tune Windows administrators want to hum.

Dick Pountain

The high cost of maintaining Windows PCs has become a strategic issue as Sun and its allies challenge Microsoft's domination of the desktop with their centrally maintained network computer (NC) concept. Microsoft countered with the hastily concocted NetPC standard. But behind the scenes it's readying Citrix's MultiWin technology as a not-so-secret weapon in the cost-of-ownership wars.

MultiWin boosts NT so that many users can run applications such as Word and Excel simultaneously on the same server, driving them remotely from user interfaces running on inexpensive terminals. Unlike NCs, these client terminals don't need to download any OS or application code, so they can be very "thin" indeed. Citrix claims a minimum hardware requirement of an Intel 286 processor or equivalent and 640KB o f RAM, far skinnier than any NC or X Window System terminal. An independent report found that 30 MultiWin clients can run Excel simultaneously on a twin-Pentium server without taking a big performance hit.

Like X, MultiWin works by packing up the Graphical Device Interface (GDI) commands that ordinarily control an application's local display and sending them across a communications link to the client for execution ( see the figure ). The client doesn't have to be a PC; it can be a Mac or a Unix workstation running suitable client software. Citrix has invented an efficient protocol, called Intelligent Console Architecture (ICA), to send the display commands.

Unlike the bit-mapped scree n images that a conventional remote-control program would send, ICA messages are very compact, needing as little as 20 Kbps of bandwidth to interactively control a typical Microsoft Office application. Thus, humble transports, such as 10-Mbps Ethernet, ISDN, and even 28.8-Kbps modem links, are adequate -- they act as thin wires for thin clients. ICA can run over all the popular network protocols, including TCP/IP, IPX/SPX, NetBEUI, and PPP.

Citrix developed the MultiWin technology for its own WinFrame application server, which already has 500,000 users worldwide. Microsoft purchased a license for MultiWin and rolled it into Windows NT5.0, under the code name Hydra. Microsoft is substituting its own T.Share protocol (which is used in NetMeeting) in place of ICA, but Citrix will offer suitable adapter software to its own user base.

MultiWin/Hydra will enable roving laptop users to dial in to mission-critical applications running on their home server and allow task-based users of green-scre en mainframe terminals to painlessly upgrade to Windows applications. Expect the technology to also turn up in special-purpose terminals, from street kiosks to pocketable PDAs. Desktop Windows terminals are expected to cost around $500; the server and client software cost is currently $200 to $400 per seat.

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Where to Find

Citrix

Ft. Lauderdale, FL
Phone:    954-267-3000
Internet: 
http://www.citrix.com




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ICA Servers Shoulder the Load

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ICA enables application logic to execute on the WinFrame multiuser application server.

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Citrix in 1998

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AT A GLANCE: MultiWin technology turns W indows NT Server into a multiuser OS: It lets you run desktop applications on a server while controlling them from inexpensive terminals.

WHO SUPPORTS IT: Bell Mobility, British Telecom, Chase Research, Compaq, Dell, Dr. Solomon's Software, Eicon, Equinox, Hyperion Software, IBM, Insignia, Intergraph, Microsoft, Multi-tech, Novell, Sequent, Shiva, Tektronix, Ventana, Wyse.