Sun is to offer its Solaris operating system free for "non-commercial" use, the company said yesterday. Sun's version of Unix is already heavily-discounted for educational customers, but the latest move seems to represent a determined effort to expand use into other markets. This is the route Linux, the freeware Unix implementation that has recently been attracting support from major application developers, has taken, and although Sun denies that it's specifically targeting Linux, the example probably played a part in the decision. Sun will be making Solaris available for free on both Sparc and PC platforms, and in the latter case it will hope to benefit from enthusiasts, voluntary and cash-strapped organisations just as Linux does. Giving the OS away won't seriously damage Windows sales in the short run, but it's certainly likely to broaden Sun's base, and stimulate application development a la Linux.