SCO Goes Hunting for Citrix Customers

Until now, UnixWare company The Santa Cruz Operation Inc. (SCO) has been little-known to NT aficionados. That situation is about to change. As of today, SCO has declared open season on NT thin-client provider Citrix Systems Inc.

SCO's Tarantella Enterprise II, shipping this week, expands the company's thin-client offerings to include NT applications - an area monopolized by Citrix and its primary licensee, Microsoft.

The move is bound to garner attention - if for no other reason than the economic implications. SCO has loaded both barrels with a 10-for-1 Citrix MetaFrame license replacement program. Growing enterprises that decide to dance the Tarantella will reap a significant financial windfall. Want to trade in those 50 Citrix licenses? SCO will replace them with 500 of its own.

I've scoured the substantial literature available at SCO's Tarantella site (, and it certainly appears that the company has a credible offering.

Like Citrix, SCO implements what it terms a "thin display engine" as a Java client as well as a "native" client for environments such as Windows 3.1, where running Java is painful or impossible.

While citing no specifics, SCO claims that dial-up performance via Tarantella is comparable to running applications locally across a fast LAN. Citrix makes the identical claim. Feature-for-feature, this product is positioned squarely against Citrix. But there are some critical differences.

Like Citrix's MetaFrame, Tarantella is used in conjunction with the basic Windows NT/2000 Terminal Server Edition (TSE). TSE is built using base thin-client code that Microsoft licenses from Citrix. The product communicates with TSE using the proprietary Microsoft Remote Desktop Protocol (RDP). Unlike Citrix, whose engineers developed RDP, SCO engineers reverse-engineered the protocol.

Microsoft, it seems, was in no rush to work out a deal with the only credible competitor to Citrix. To its credit, SCO refused to be stonewalled by Microsoft.

Still, given the relatively mysterious nature of RDP, Microsoft and Citrix will have no problem using SCO's "bootleg" code to instill fear, uncertainty and doubt in any potential converts.

For its part, SCO should promote what it has done and seek to demystify RDP.

Heck, the company should even post its decodes and offer them up to vendors of network analysis tools. I believe that Tarantella's success or failure will hinge upon how SCO handles the RDP issue.

There is another significant issue that is buried deep in the SCO material.

Whereas the Citrix server-side code is coresident with TSE, Tarantella is not.

It runs on a different server.

In any case, Citrix cannot afford to ignore SCO's play. Before long, the hunter may become the hunted.

Tolly is president of The Tolly Group, a strategic consulting and independent testing firm in Manasquan, N.J. He can be reached at (732) 528-3300, or