http://www.kroah.com/log/2004/09/26#2004_09_26_sun_rebuttal_round2

and I like this summary of some of the areas where Linux outshines Solaris. The list is interesting because its not a list of features (it’s relatively easy to add features) it’s an architecture and approach related list:

Device support - As I mentioned before, and as you mentioned, Linux’s device support is unmatched anywhere else. We support, out-of-the-box, more devices than any other operating system. We also support them on every platform that Linux is supported on (somewhere over 21 unique architectures with lots of minor arches last I looked). That’s power and flexibility that enables customers to start out with a small Linux box (running on a cheap i386 clone) and if needed, they can go out and buy a ia64, or amd64 box, and use the same investment in devices (disk controllers, etc.) and with no changes to their applications (other than a recompile) and “just work”. This also enables customers to not have to rely on any one specific hardware vendor, preventing any “lock in”. They can pit HP vs. IBM vs. Dell vs. the whitebox dealer down the street, or just build machines themselves (like a lot of places do, Google for example), in order to get the best service and price and support for their specific situation. That’s incredibly powerful for the customer/user, and very scary for the big companies that previously had relied on the cost that a customer had spent already to tie them to that company for a long time.

Speed – Last I looked, Linux beat the pants off of any other operating system on the same exact hardware configuration. Both in microbenchmarks like lmbench, and in macrobenchmarks like specweb and TPC numbers. I’ve seen loads of unpublished results at a lot of different companies for these macrobenchmarks backing this up (unpublished usually due to the cost of publishing them, and for political reasons because the company also sold other operating systems on the same hardware, and didn’t want to loose those customers in large numbers.) And, I’m sure the fact that we don’t have to keep around old, broken apis, or have padded structures to keep binary compatibility might have a little to do with this speed advantage

Flexibility - I touched on this up above in the device support point, but Linux scales from very tiny to very huge systems, all based on the exact same kernel code base. We support mmuless embedded devices, and NUMA systems. No other operating system can claim that kind of flexibility that I know of (ok, maybe NetBSD, but it doesn’t support the range of devices that we do…) But aside of the system flexibility, Linux’s main flexibility is that if it doesn’t do something you want it to do, then you can change it to do it yourself. If you are a customer, and really like Solaris, but happen to want to use it to put it into your barcode scanner, you can either try to convince Sun to do this for you, and pay them a whole lot of money, or you can find a os that can do this. Sure, I know you will say that Solaris isn’t in that market, and that they are only going for the enterprise, which is a completely valid response. It’s just that Linux meets the needs of everyone, not just a single market segment. It’s this point that will ensure that any feature that is missing from Linux, will allow it to be easily added.

http://blogs.sun.com/roller/page/eschrock/20040924

You can sum up the response with the following:

Sigh. It’s one thing to believe in sound engineering values, and quite another to develop them as an integral part of your OS . I’m not saying the Linux doesn’t care about these things at all, just that they’re just not a high priority. The original goal of my post was not “our technology is better than yours,” only that we have different priorities. But if you want a technology comparison, here are some Solaris examples:

http://www.kroah.com/log/2004/09/23/#2004_09_23_sun_rebuttal