|S N E A K P R E V I E W|
SCO Tarantella Offers New Twist On an Old Thin-Client Dance
January 24, 2000
By Mark Andrew Seltzer
Application deployment in a network environment is always a chore. The fundamental design of Microsoft Corp.'s Windows makes it difficult to install applications on a server and deliver them to desktop computers. Automated software-distribution systems hold some promise, but add significant complexity. And even if the installation process can be automated, new versions of software often require hardware upgrades if they are to maintain acceptable performance. It's no wonder that thin-client computing environments such as Windows NT Terminal Server and Citrix Systems' MetaFrame have enjoyed explosive popularity, but this approach has a down side, too, since a proprietary client-side application is still needed on each desktop PC. There must be a better way--and its name may be Tarantella Enterprise II.
Tarantella offers a new twist on thin-client computing, and it packs extraordinary Web-based functionality. Developed by SCO, Tarantella lets users access and run applications hosted on Windows NT Terminal Server, Unix X Window servers and legacy mainframes with little more than a Java-enabled Web browser. Tarantella Enterprise II runs in conjunction with a Web server on a variety of Unix platforms, including IBM Corp.'s AIX, Hewlett-Packard Co.'s HP-UX, SCO UnixWare and Sun Microsystems' Solaris. SCO says it plans to release a Windows NT version next year; additional versions for other Unix variations are scheduled to be released by the time you read this.
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.
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.