Personally, I've found this to be somewhat of a non issue. Each OS has its advantages and disadvantages. I've found Solaris x86 to be more reliable. For example, I used to run my web server on Solaris x86 and it ran 8 months without a crash. Under Linux, it runs at most 6 weeks before needing a reboot. There are various bugs in Linux in the kernel, nfsd, memory leaks, etc that caused crashes. For our NOAAPORT system, Solaris x86 has been rock solid and can run for months without a problem. I've also seen that Solaris x86 will run CPU and disk intensive applications much faster (10-20%) than Linux. Then there is the issue over BUGS... Linux is notoriously buggy which sends users scrambling for bug fixes. Even though these aren't serious 95% of the time, its still frustrating. Solaris has its pluses because of its stability and that little has changed in Solaris in the last 5 years. Also, Solaris has much better 3rd party device support especially in the areas of data acquisition. Many of these hardware groups are just now starting to support Linux. So for server issues, I'd probably pick Solaris x86 over Linux. Then there is the other hand... Documentation for Solaris x86 is virtually non-existent. If you are a Solaris guru, you're set. Otherwise, you're stuck either with a $40 book from Borders or $1000 worth of CDs from Sun. Even then there is no guarantee these will answer your question. I've yet to get a single question answered through Sun's online Solaris knowledge base. Most of these are due to the fact there is virtually no support for Intel version on Sun's web site. I've hit many brick walls in the Solaris environment that I couldn't extricate myself from without paying an arm and a leg. Linux's online help (man pages) and web knowledge databases have come to the rescue many times. The user environment for Linux is MUCH nicer than Solaris. Solaris, CDE and other standard tools have changed little in 5-8 years and are showing their age. Linux GUI environment and tools have kept up to date and are continuously adding new features. You could get the source for many of these packages and compile them for Solaris but this is time consuming. So for a user and development environment, I really prefer Linux. Then there is the issue over new hardware support. Solaris x86 seems to lag 9-18 months behind the curve of support for new hardware. This means you can't get the latest and greatest PCs from Dell, Gateway and Compaq and think all the COTS hardware will be supported. We've often found ourselves replacing newer hardware with older in order to get Solaris x86 to support it. For example, we had conflicts recently with networking and graphics cards which has sent us out looking for old 3COM and Intel Ethernet cards and settling for 640x480 VGA mode for graphics. Also, we've had a nasty problem with Solaris 7 not supporting hard drives greater than 8GB. So we have a ton of users in the field who need more disk space to support NOAAPORT and get a 20 GB drive and finding Solaris will only partition 8GB of it. So here... we use both. We use Solaris for mission critical/operation systems that need the reliability. We use Linux for development and quick deployment. We use Linux for the web environment because of the tools that are bundled with the operating system such as X11R6/Xvfb and others. As for interoperability, I've found that Linux is the closest to Solaris of most Unix systems. Solaris went its own route about 5 years ago, straying from the SysV route that IBM AIX, HPUX and others went. Linux has thanks to GNU, tried to stay reasonably compatible with Solaris so moving back and forth is not a big issue. The bottom line is.... go with whatever you are familiar with. It may be a religious issue. I know most universities have a long history of support for Solaris and wish to continue that route. I know others which have gone Linux due to its low cost and support. Dan.