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The Tarantella client is browser-based, which means it can be used on almost any platform that supports a Java-based Web browser, including Netscape Communications Corp.'s Navigator or Microsoft Internet Explorer.

In Network Computing's Real-World Labs® at Syracuse University, I installed a prerelease copy of Tarantella Enterprise II and Windows Connectivity Pack on a Sun SPARC5 Server with 512 MB of memory. While a variety of Web servers are supported, including Netscape, I installed them with version 1.3.9 of the Apache Web server. The installation of the Beta 2 release went smoothly, though I had to change many settings within the Web server to make it work properly with Tarantella. Most notably, the Apache server's default port configuration (8080) did not work correctly with the beta version of Tarantella, which appeared to append the port number to the end of all images and links on the site, causing dead links (for example, server.org:8080: 8080). Once I changed to the standard Port 80, Tarantella worked fine.

Connection Jitterbugs
Testing a minimally configured Dell Optiplex running Windows NT 4.0 with Netscape Navigator 4.7, I attempted to connect to the server, but upon downloading Tarantalla's Java client application, Netscape promptly crashed. I was unable to rectify the problem immediately on that system, so I tried a different Dell Optiplex system running NT 4.0 and Service Pack 5, which worked right away. After successfully initiating a browser session with the Tarantella server, I was prompted to download its Java client application. Then I logged in as administrator and accessed the Tarantella Webtop--a customizable Java-based application manager similar to Windows Explorer. As an administrator, I accessed the Control Center, which let me add users, modify security privileges and add applications to be accessed from Tarantella clients.

I tested Tarantella as a broker for both Windows and Unix applications. Through the Control Center, I added application icons that let me access Windows applications on an NT Terminal Server host using Microsoft's RDP (Remote Desktop Protocol). It supports RDP, so users need not install Citrix's MetaFrame on the NT server, though Tarantella does support Citrix's ICA protocol. Applications can be displayed either in the Webtop widowed mode (within the browser window) or in full-screen mode. I also tested a variety of X-based Unix applications using the X-11 protocol, including simple Xterms and a Solaris version of Navigator. All applications performed well in our test configuration.

SCO built Tarantella to allow for scalability and load-balancing of Tarantella servers. When multiple Tarantella servers are on a network, they can be tied together for load-balancing. The Tarantella servers appear to the user as one system and allow for single-point administration and single-point logins. If one Tarantella server goes off the network, users are automatically routed to another.

Tarantella technology was designed to be used primarily in a LAN environment, but I tried connecting over a 26,400-bps modem. Performance was sluggish, but tolerable for text-based and word-processing applications that don't require the screen to be redrawn. Tarantella also ships with a security pack to implement SSL when connecting to Tarantella over dial-up or insecure Internet connections.

SCO offers two Windows-based "native clients," which run on the desktop PC as an alternative to its Java-based version. SCO includes a 16-bit version for Windows 3.1 and a 32-bit version for Windows 9x and NT. The native client runs without the presence of a Java-enabled Web browser. SCO says this client is useful on underpowered legacy Windows machines, which are incapable of running a Java-enabled Web browser.

SCO stresses the importance of running its software on a separate operating system from a Windows NT server because NT is more likely to crash or blue screen when it is presented with third-party (non-Microsoft) services such as Tarantella. Tarantella avoids this by running its application on a Unix platform that can be completely separate and isolated from the Windows Terminal Server.

Another impressive feature of Tarantella is "follow-me" printing, which lets printer output be directed to the correct printer according to the node to which you are connected. If a user is connected from home, Tarantella is able to print to his or her home printer, but at the workplace, it will print to the specified network printer on the user's LAN.

Mark Andrew Seltzer is a Syracuse, N.Y.-based freelance writer. Send your comments on this article to him at Mark@Seltzer.org.