One carrot would appear to be Java, an area where IBM has been a tireless advocate, partner and investor. Some think the Java brand may be valuable enough to entice IBM, but not at the rumored US$6.5 billion price tag for the whole of Sun. Others say the Java franchise is in a lull that seriously downgrades its value.

"Sun has tried over a 12-year period to be a leader in Java middleware and they have not accomplished much," says Dana Gardner, president and principal analyst for Interarbor Solutions. "And it tried to double down with open source projects such as Glassfish and , but the Java Community Process right now is probably the weakest it has been."

GlassFish is an open source application server, while OpenSolaris is the open source implementation of Sun's Solaris operating system.

"If IBM thought highly of OpenSolaris or GlassFish, there is nothing preventing them from developing around the community process and creating code," says Gardner.

The same could be said for productivity software, where Sun has developed StarOffice off the OpenOffice.org project while IBM has developed Symphony around the same code base.