A possible IBM acquisition of Sun Microsystems might have its good points. But users and analysts also have concerns that can be summed up in two words: uncertainty and fear.

Sun may be a diminished company these days, but it remains an influential one. Through its open-source products and the massive development communities that have been built up around them, Java and MySQL in particular, Sun has a pull that rivals those of companies with far larger and healthier balance sheets.

But with the reported acquisition talks between IBM and Sun, there are questions about what IBM might do with Sun's technologies,particularly Java and open source products.

Analysts warn of uncertainty around IBM bid for Sun Forrester analyst James Staten said, “IBM has wanted to get its hands on Java for some time as it is a key intellectual property for WebSphere.” However, Java developers are anxious about whether the comparative openness that surrounds Java would survive an IBM takeover.

Gordon Haff, an analyst at Illuminata, sees an inherent conflict between Sun's open-source culture and what he thinks is IBM's continuing proprietary direction. Although IBM has been a supporter of Linux, its embrace of the open-source operating system "is in the context of what serves IBM," Haff said.

That tack is even more obvious in the database market, according to Haff. Buying Sun would give IBM the MySQL open-source database, which Sun acquired last year. But, Haff said, "IBM doesn't push open-source databases, they push DB2."

There are a range of possible motives for why IBM might want to acquire Sun. Such a deal could be a defensive manoeuvre against Cisco Systems' decision to enter the server business and try to play a more prominent role in datacentres, long the domain of companies like IBM, Sun and Hewlett-Packard.

IBM also could be looking to bolster its ability to compete against Microsoft via technologies such as Linux and Java, and some observers think that MySQL would be an attraction for IBM.

And of course, Sun is still a major hardware vendor with a considerable installed base, even though the struggling company has bet its future on the success of its open-source strategy and its emerging cloud computing services. Sun's overall revenue dropped 11% in the quarter that ended in December, but the company still reported server sales of about $1.2 billion during that period.

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Sun's line of servers based on its own Sparc processors and Solaris operating system could face an uncertain path under IBM, which sells systems built around its Power processors and AIX software that compete directly with the Sun machines.

Another consideration is that fact that the market shares of all the major Unix operating systems - AIX, Solaris and Hewlett-Packard Co.'s HP-UX - have been eroding in the face of competition from both Windows and Linux.

But Unix systems continue to be embedded within many companies, often as the platform of choice for mission-critical applications and databases.

"Sun is a company that has been based on and driven by the work of mavericks," said Charles King, an analyst at Pund-IT. "I think it's critical for IBM to somehow maintain the culture of Sun in a way that preserves that history of innovation. It's one of the great things about Sun."

Sun's future "has been uncertain, and their financial performance uninspiring, for some time," said Rob Enderle, an independent analyst in San Jose. "IBM, on the other hand, has emerged as nearly invulnerable in this market, having shifted largely to a services and software model."

Enderle thinks that putting Sun under IBM's control would reassure existing customers and stabilise Sun's user base. And, he said, Sun's intellectual property holdings, in particular its software, "could significantly bolster IBM's portfolio for the battles for the cloud that are to come."

Forrester analyst James Staten said “We would expect Java, Solaris, MySQL, and Indentity Management Suite to live on with the new company with the possibility of GlassFish, NetBeans, Open ESB, and Java CAPS being spun off into open source projects if they are to continue on.”

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