Jesus, not this one again. First of all, yes, Linux has low code quality. If you missed that, you are really revealing your ignorance. Maybe you should read up on Linux instead?
You want proof of the low code quality? Here, straight from the Linux kernel developers themselves.
"The kernel is huge and bloated, and our icache footprint is scary. I mean, there is no question about that. And whenever we add a new feature, it only gets worse."
Andrew Morton says:
"I used to think [code quality] was in decline, and I think that I might think that it still is. I see so many regressions which we never fix....it would help if people's patches were less buggy."
"The [linux source code] tree breaks every day, and it's becomming an extremely non-fun environment to work in....We need to slow down the merging, we need to review things more, we need people to test their f--king changes!"
And also other developers agree that Linux code is bad.
"[Linux] is terrible," De Raadt says. "Everyone is using it, and they don't realize how bad it is. And the Linux people will just stick with it and add to it rather than stepping back and saying, 'This is garbage and we should fix it.'"
IT company CEO: "You know what I found? Right in the [Linux] kernel, in the heart of the operating system, I found a developer's comment that said, 'Does this belong here?' "Lok says. "What kind of confidence does that inspire? Right then I knew it was time to switch."
I have more links from Linux kernel developers. One say "The kernel is going to pieces". You want to read those links? Just tell me and I post more links for you.
The conclusion is: Yes, Linux code quality is poor. Even Linus and other Linux kernel developers say that. I am just repeating what they say. If you want to attack me, dont. Attack instead Linus, Andrew, etc - I just quote them. Dont shoot the messenger.
Regarding the top-500 supercomputers running Linux. Jesus not that one also. Those supercomputers are just a huge cluster on a fast network. Just add a new node, and you improved performance. Anyone can do that. Just like this SGI machine, which runs tasks which are embarassingly parallell. Have you ever heard about P-complete problems? Or NC-complete? No? Study som parallell algorithm complexity theory, then. And then, come back.
Regarding top-500 list, it says nothing. On 6th(?) place we find the IBM Blue Gene. It is one of the fastest supercomputers in the world. It uses 750 MHz POWERPC cpus. Does that mean that the POWERPC cpus are among the fastest in the world? No, it doesnt mean nothing. Top-500 runs Linux, because Linux is easy to strip and modify. Google runs modified Linux kernel, I have a link about that. Not here at work, but when I come home I can post it for you.
Linux is easy to modify. It is a naive kernel. It is not scalable. There is no way in hell it scales to 1000s of cores. Linux developers have never had access to servers with 8 cpus or more. Linux is not tailored to that many cpus and it scales bad. But for clustered solutions (just a network), Linux is fine.
Here we have a bunch of Linux scaling experts that "dispels the FUD from Unix vendors that Linux does not scale well" in an article:
"Linux has not lagged behind in scalability, [but] some vendors do not want the world to think about Linux as scalable. The fact that Google runs 10,000 Intel processors as a single image is a testament to [Linux's] horizontal scaling.
Today, Linux kernel 2.4 scales to about four CPUs
"-With the 2.6 kernel, the vertical scaling will improve to 16-way. However, the true Linux value is horizontal scaling [that is: clusters].
Q: Two years from now, where will Linux be, scalability-wise, in comparison to Windows and Unix?
A: It will be at least comparable in most areas"
According to the Linux experts, Linux scales to 10.000 cpus in one single image in the current v2.4, and in Linux 2.6 the kernel will improve to 16-way? Isn't that a bit strange? It doesnt add up, does it? Do you Linux fan boys ever think a bit?
The ALTIX machine sold in year 2006 with 4096 cores, was using Linux v2.6 (which had only been released 2 years earlier). I find it extremely hard to believe that in v2.4 Linux scaled bad (2-4 CPUs) and two years later it suddenly scales to 4096 cores in the ALTIX machine? It takes decades to scale well. The only conclusion is that ALTIX machine is a cluster, otherwise Linux would have not chance to scale to 4096 cores in two years.
Linux scales well on large clusters, yes. But that is not Big Iron. When people says Linux scales well (which it does) then they talk about clusters - that is scaling Horizontally.
In other words; Linux scales well HORIZONTALLY, but still not good at VERTICAL scaling (that is those huge Unix servers with 64 cpus weighing a ton)