A move by four sellers of Linux to unite behind a single version of the operating system might help those allies--and boost Linux's popularity--but it isn't likely to dent the dominance of the top dog, Red Hat. Turbolinux and Caldera International in the United States, Conectiva in Brazil, and SuSE in Germany announced Thursday that they will merge their separate Linux products into a single version called UnitedLinux by the end of the year. The intent of the plan is for the companies to share research costs and to make it easier for software and hardware companies to certify that their products work with Linux.

Although the move might boost the allies' fortunes modestly, it probably won't turn the tables on dominant Linux seller Red Hat. Even pulling together, the UnitedLinux allies simply don't have enough clout to influence the market, said analysts. "Very little will change," said IDC analyst Dan Kusnetzky, who monitors the worldwide sales and revenue of Linux and other operating systems. "If you add up all those people's market share by shipments, it adds up to less than 20 percent of the market. Red Hat has at least twice that share."