The problem of providing users with access to all the applications they need to do their jobs can be huge. And if those users work on a variety of platforms, the problem can seem unsolvable. SCO's Tarantella takes a stab at providing a unique solution. Based on our tests of the product, however, the first release of Tarantella is a half measure; it requires significant help from third-party products to deliver on SCO's promise of providing universal client access to applications running on any platform.
Tarantella is an application-brokering platform, meaning that the product works between applications running on various back-end machines, such as a Unix host and a browser-based client, to provide an interface to the application. Overall, we found that this approach worked well. On its own, however, Tarantella delivers browser-based access only to Unix programs. To access other applications, such as a mainframe or Windows programs, you'll need products from third parties.
For access to Windows applications Tarantella requires Network Computing Devices' (NCD's) WinCenter, which provides a remote interface to those applications for X-Window clients (or servers, as they're called in the Unix world).
Tarantella treats the WinCenter-provided program as a typical X-Window application when presenting it to a browser-based client. The trick is that WinCenter actually runs on Citrix's WinFrame platform, which provides remote access to Windows applications running on a modified version of Windows NT 3.51 server.
Fortunately, NCD ships a copy of WinFrame with its WinCenter product, so there's no further charge; but you'll still pay extra if you want to use WinCenter with Tarantella, which already carries a steep price tag on its own, starting at $300 per user. The thing that really left us scratching our heads was that we could already get browser-based access to Windows applications through WinFrame. So why all the application runaround with WinCenter and Tarantella?
SCO also turns to third parties to provide access to mainframe or minicomputer applications. Although you can use Telnet to connect to a mainframe or AS/400 from a Tarantella-hosted terminal session, there is very little benefit to this approach over using a typical Telnet application on your client machine. There are, however, benefits from using a richer 3270 or 5250 terminal-emulation program; SCO has formed partnerships with Computer Network Technology, Interface Systems, and StarQuest to provide these capabilities through Tarantella. For now, this capability requires an extra purchase, but SCO plans to add to Tarantella the host connection for 3270 and 5250 terminals sometime in 1998.
We did like the overall interface of Tarantella, which provided each user with a Java-based console or "Web-top" that contained a menu of each user's assigned applications. And the applications that we set up and used performed adequately. However, given the performance of the Java code, you can expect to wait while applets initialise when connecting to Tarantella - especially with slow clients or over a slow connection, such as with a modem. The product worked well on the different platform and browser combinations we tested, although we did notice some problems, particularly on our Macintosh client.
We were able to set up new applications and users fairly easily, as well as assign users a number of applications. When creating user accounts, the product by default refers to the local user account on the Unix host to authenticate clients for Tarantella.
This is convenient, but it also means that we had to set up two accounts - one on the Unix host and one in Tarantella - to get the job done. We felt the product could have done more to synchronise users' accounts on both systems.
One welcome feature allowed us to resume a client's access to a running application if, for example, the user's connection to the server terminated. We were also able to kill suspended user sessions with the Control Centre.
However, we were unable to delegate to users any administrative functions without having to grant full management access to Tarantella.
One key advantage of Tarantella is that it can provide access to applications running on various back-end servers, and not just to the server hosting Tarantella. (This is unlike Citrix's WinFrame and Microsoft's forthcoming multiuser version of Windows NT, code-named Hydra.) Tarantella's approach gives it an innate distributed-processing architecture.
Unfortunately, there is no way to configure the product to automatically balance the load for a particular application across several back-end servers.
You could achieve this end, however, through a painstaking manual process.
Tarantella's approach to universal application delivery is certainly a good concept, and this debut offers some nice capabilities. However, the product just doesn't go far enough in this release to provide universal client access to cross-platform applications and hosts.
If you're willing to bear the price, and you're concerned only with delivering Unix applications to disparate client operating systems, then Tarantella may be a good choice for you. But, if you also need to deliver Windows applications and mainframe connectivity, then be prepared to write more than one cheque.
SCO's Tarantella provides browser-based access to Version 1.0 Unix applications, but fails to deliver support for Windows and mainframe applications without help from third-party applications.
Pros: Easy to install; works with local user-security profiles; can provide access to applications running on a number of back- end servers; allows client to resume sessions if disconnectedCons: Pricey for its capabilities; requires extensive third-party support to deliver non-Unix applications; Java reliance will affect remote application performancePlatforms: Tarantella server runs on SCO UnixWare 2.1.2 and later and Sun Solaris 2.4 and later with a CGI-compatible Web serverPrice: Starts at $590 per user for a single- user licence; $300 per user for a 500- user licence.
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