Thin Is In

The client/server world measures a client's fatness by how much of an application runs on the workstation. According to industry analysts, fat increases total cost of ownership (TCO) because of the maintenance required to keep the client workstation running. Oracle and Sun Microsystems use this analysis to claim that network computers (NCs) reduce the fat, and therefore, can save organizations money.

CUT THE FAT
TCO has sounded the biggest wake-up call to the PC industry since the Internet. For the past year, the PC industry has been reacting to the TCO message. TCO has fueled the fire behind NCs, Network PCs (NetPCs), managed PCs, and more. Although PCs have increased user productivity compared with dumb terminals, PCs have also increased systems management costs. In a recent study, "The Real Cost of Network Computing" (Computerworld and IDG Research), most IS managers said that implementing PC-based networks has increased costs for staffing, hardware, software, training, support, consultants, and network maintenance. In response to this situation, TCO awareness has pointed a finger at suppliers and said, "Enough."

TCO causes businesses to rethink how to deploy clients in the enterprise. You face several strategies, which Figure 1, depicts. I group client strategies into three categories: thin, lean, and fat. I'll introduce these strategies, present key players in the industry, and focus on thin clients. A future article will concentrate on lean and fat clients, and how to decide which strategy is best for your environment.

Buying a client device is like buying a container of milk: You must decide whether you want skim, 2 percent, or whole. Regardless of the solution you choose, it must meet certain goals to reach TCO objectives: Client devices must be truly network-centric, letting anyone access anything, at anytime, from anywhere; users must be able to access legacy applications safely and securely from any location; you must be able to centrally control desktops to allow for easier software maintenance and upgrades; your solution must be secure and, of course, reduce costs.

THIN CLIENTS
A thin client is a network-dependent terminal capable of displaying remote applications running on an attached server. All applications, processing power, and user configurations reside on the server.

Imagine rolling out an Office 97 upgrade to your enterprise in only two hours. This scenario is the promise of thin client technology because you register the application with only a central server. You set all your user profiles and configurations at the server. Office 97 runs on the server and sends only screen updates across the wire to the terminals. You change nothing on the client devices.

Contrast that scenario with a typical PC client-based enterprise network. Even if you run Microsoft's Systems Management Server (SMS), each user must respond to an upgrade notice, wait until the application installs on the local hard disk, and then answer the appropriate prompts. If you're not running a software distribution program such as SMS, you must install the upgrade at each PC. If the PC needs more memory, more disk space, or a faster CPU, your upgrade could take months.

Because a thin client doesn't perform any processing, thin client environments require huge servers. For typical business applications such as Office 97, a 4-way Pentium Pro-based server with 512MB of RAM can service 60 users (15 users per CPU and 128MB of RAM). In a fat client environment, that 4-way server could handle 600 file-and-print users.

Stuck on NT Server 3.51
Today's thin clients are based on multiuser Windows NT Server extensions from Citrix Systems and Prologue Software. When you install these solutions, you install a modified version of NT Server 3.51 that includes the multiuser application server software as services in the core OS. Prologue replaces 29 files, and Citrix replaces 430 files from the standard version of NT Server 3.51. Both solutions modify NT's kernel (ntoskrnl.exe).

When Microsoft released NT 4.0, both Citrix and Prologue sought to build their solutions on this new version. Microsoft no longer wanted modified versions of NT in existence, seeking to have total control of the operating system. For a while, how Citrix and Prologue were going to update their NT Server 3.51 multiuser extensions was unclear. Last spring, Microsoft licensed Prologue's software and Citrix's multiuser extensions. This licensed code forms the basis for Microsoft's thin client solution (code-named Hydra), which I'll describe later in this article. As part of the license, Microsoft has agreed to upgrade existing Citrix and Prologue sites with Hydra for NT Server 4.0 (and future versions of NT).

Unfortunately, until Hydra ships (some time in 1998--beta 1 will come out in the fourth quarter of 1997), the only thin client solutions available are based on NT Server 3.51. Therefore, any application that requires NT 4.0 on the client won't work.

WinFrame Model
Citrix has created an NT-based thin client market by shipping over 30,000 WinFrame servers. In a recent survey of Windows NT Magazine readers, 6 percent of you stated that you have Citrix-based servers, and an additional 6 percent of you plan to purchase Citrix-based servers over the next 12 months.

The current Citrix software includes three parts: NT Server, multiuser NT extensions (MultiWin), and Intelligent Console Architecture (ICA) client/server technology. For NT Server 4.0 and later, Citrix-based solutions will include NT Server, Hydra, and ICA. Citrix retained the rights to ICA, a core client/server technology that supports a large number of devices. The ICA client, which is available for NT, Windows 3.11, Windows 95, DOS, Macintosh, and UNIX, is a small piece of software that lets client devices display information sent by the ICA server. The ICA protocol sends only keystrokes and screen updates across the wire.

Why didn't Microsoft purchase the ICA client/server technology? "ICA is Citrix. To get ICA, Microsoft would have had to buy Citrix," said Mark Templeton, Citrix's marketing vice president. ICA clients can run anything that can run on NT Server 3.51, including Java-based applications.

Citrix has licensed its technology to several terminal manufacturers who have embedded an ICA client into their hardware devices. For example, Wyse Technology has created an ICA-based terminal called Winterm. Early adopters who bought Winterm clients when 486s were the standard have already bypassed two complete upgrade cycles. They simply upgraded their WinFrame servers and application software. They didn't need to make any changes to their Winterm clients.

Citrix has also licensed its WinFrame server technology to Tektronix, Network Computing Devices (NCD), and Insignia Solutions. These companies have added capabilities to WinFrame to emphasize specific areas of the market, including non-Windows clients such as Macintoshes and X-terminals.

NCD adds X-Windows support and other features to WinFrame and calls its server product WinCenter Pro. With the NCD solution, you can use existing X-terminals, commonly found in UNIX shops. WinCenter Pro lets thin client users copy text between X-Windows and Windows applications. NCD also manufactures X-terminals, NCs, and Windows-based terminals. When coupled with WinCenter Pro, this hardware and software combination provides a thin client solution.

Like NCD, Tektronix adds X-Windows support to WinFrame and calls it WinDD. WinDD has created ICA clients for the seven major UNIX platforms. Tektronix manufactures a variety of thin clients with protocol combinations. For example, you can buy terminals that natively support a combination of X, ICA, and 5250. With this combination, one terminal can attach to a UNIX Server, a WinDD server, and an AS/400, and display applications from their native environments.

Insignia adds support for Macintosh, X-Windows, and Java-based NCs to WinFrame and calls its product NTRIGUE. The goal of NTRIGUE is to let any device (fat, lean, or thin) run Windows-based applications. Insignia's newest product, Keoke, is a Java-based X-Windows terminal emulator that lets NCs and Java-enabled browsers access Windows applications via NTRIGUE. "We prefer to be the arms merchant in the battle between NCs, Windows terminals, and PCs. We support them all," said Peter Crosby, the product manager for Insignia's NTRIGUE.

Application configuration is a big concern for multiuser application servers. For example, software companies typically have not designed 16-bit applications to work in a shared environment. During installation, 16-bit applications assume they have total control of the PC and attempt to install .ini files in the system directory instead of a user directory. Similarly, some 32-bit applications write temporary files using fixed names in common locations (e.g., the TEMP directory), or they store information in HKEY_LOCAL_MACHINE instead of HKEY_CURRENT_USER.

Citrix intercepts about 80 percent of such installation problems, but the remaining 20 percent of the problems require workarounds. Insignia has dedicated a Web page (http://www.insignia.com/NTRIGUE/Application.html) to application configuration notes to help you overcome these problems. In addition, the company has developed an application configuration tool (ACT) to automate installing and configuring problem applications.

WiNTimes Model
Prologue Software and Exodus Technology have co-developed the WiNTimes multiuser NT technology, which runs as an NT service on top of a modified version of NT Server 3.51. Exodus' NTERPRISE combines NT Server 3.51, WiNTimes, distributed display technology, and a client/server protocol.

Unlike Citrix, which uses the ICA protocol, Exodus bases its client/server protocol on X (more than 16 million terminals use X today). If a client can use X, that client can access Windows applications via NTERPRISE. In addition, Exodus supports the Alpha platform, which Citrix does not support.

Because of its distributed display technology, NTERPRISE can sense the native GUI of the attached client. For example, if an X-terminal is accessing a Win95 application, NTERPRISE configures the application to emulate the Motif window behavior: minimize, maximize, and close. This feature lets users maintain the look and feel they're accustomed to while using the application. Users can turn the multiwindow mode feature on and off from the client.

Another advantage of NTERPRISE is Exodus' pricing model. Currently, Citrix-based solutions charge a client access license (CAL) fee for every session. In contrast, Exodus charges a CAL fee for every client, regardless of the number of sessions that client uses. For example, 10 users, each of whom logs on to the multiuser server twice, generate 20 logons, or sessions. Citrix charges you for 20 CALs, but Exodus charges you for only 10 CALs.

NTERPRISE installs over an off-the-shelf version of NT 3.51 and modifies NT during installation. In contrast, Citrix bundles NT Server 3.51 with its product. Therefore, when you compare total solution prices, you must add the cost of NT Server 3.51 to the price of NTERPRISE to compare the products equitably.

Exodus positions NTERPRISE as the preferred platform for running networked, non-Windows clients, such as X-terminals. In performance tests, several vendors found that the X11 protocol performed better for locally attached thin client devices. ICA, with its compression scheme, performed better in low bandwidth situations such as WAN, dial-up, Internet, and wireless environments. With its reliance on the X protocol, Exodus positions NTERPRISE for only locally attached devices. In the future, Exodus plans to add support for low bandwidth environments.

IGC and Maxspeed
Intelligent Graphics Corporation's (IGC's) MultiNode for Windows NT uses the WiNTimes engine to support terminals that Maxspeed manufactures. Instead of using ICA or X, Maxspeed uses a direct video connection at 32Mbps. An NT workstation with IGC MultiNode can simultaneously behave as a client to a main server, and as a server to Maxspeed's MaxStation clients. This technology eliminates network traffic overhead to the MaxStations. The NT workstation remains fully operable as a local workstation when you need to access a floppy or a CD-ROM.

Figure 2 shows a typical Maxspeed configuration, in which one NT workstation hosts multiple terminals via the ISA or PCI bus. Each slot can host a MaxStation connection card, which comes in 1-, 2-, or 4-port configurations. A MaxRack lets one slot expand into a 7-port MaxStation connection. Each MaxStation connects over CAT5 wiring to an RJ45 connector. You can place the MaxStation up to 500 feet from its host.

Maxspeed positions its solution as a low-cost point-of-sale (POS) application. For example, the total price of a four-terminal solution is less than $5000. Because IGC MultiNode for Windows NT is tied to the Prologue multiuser engine, this solution runs on only NT 3.51.

Hydra Model
Microsoft bases its multiuser application server on the technology it licensed from Citrix and Prologue. Microsoft code named this project Windows NT Hydra, after the mythical multiheaded serpent. Analogously to the serpent, Hydra Server will support multiple Windows sessions from a common server. Hydra clients can be Windows-based PCs running Hydra client software, non-Windows clients (e.g., Mac or UNIX workstations) running ICA-based client software, or Windows-based terminals that contain a thin operating system--only enough to boot from the server and run either the ICA or T.Share protocol. (To run ICA clients, you must buy an ICA add-on from Citrix.)

T.Share is Microsoft's version of the International Telecommunications Union (ITU) T.120 conferencing protocol. Currently, the only application using T.Share is Microsoft's NetMeeting application. Microsoft believes that T.Share can be optimized for both local and remote performance situations, thus providing the benefits of both X and ICA.

Microsoft is creating Hydra for several reasons. First, Hydra lets Microsoft beat NC proponents at their own game. Because NCs require that Java-based applications run on the client, Microsoft can now label NCs as fat compared with Windows-based terminals that do not run software on the client.

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