Linux Has Fewer Bugs Than Rivals

sushant_bhatia_progr writes "Wired has an article stating that according to a four-year analysis of the 5.7 million lines of Linux source code conducted by five Stanford University computer science researchers, the Linux kernel programming code is better and more secure than the programming code of most proprietary software. The report, set to be released on Tuesday, states that the 2.6 Linux production kernel, shipped with software from Red Hat, Novell and other major Linux software vendors, contains 985 bugs in 5.7 million lines of code, well below the industry average for commercial enterprise software. Windows XP, by comparison, contains about 40 million lines of code, with new bugs found on a frequent basis. Commercial software typically has 20 to 30 bugs for every 1,000 lines of code, according to Carnegie Mellon University's CyLab Sustainable Computing Consortium. This would be equivalent to 114,000 to 171,000 bugs in 5.7 million lines of code."

Comments

Apple != Orange

[kin_korn_karn]

Talk about misleading stats...

The Windows XP code base includes all of the extraneous crap that gets bundled with and on top of the kernel.

The "Linux" code base just includes the kernel.

Not completely scientific

[The-Bus]

First off, what does this statement mean?

"[Linux has] 985 bugs in 5.7 million lines of code, well below the industry average for commercial enterprise software. Windows XP, by comparison, contains about 40 million lines of code, with new bugs found on a frequent basis."

So Linux has 985 bugs. Windows has bugs that appear frequently. Ok that doesn't really tell me anything. I tried to dig a bit deeper and came up with: "Coverity has not analysed the source code to Microsoft Windows because the company does not have access to the source code, Hallem said. Apple Computer's Mac OS X has a great deal of proprietary programming, but the core of the operating system is based on BSD, an open-source operating system similar to Linux."

So everything is based on estimates. Now, you know and I know that the Linux kernel has less bugs... but this is a tentative (at best, shoddy at worst) way of presenting that idea.

Re:20-30 bugs per 1000 lines???

[Iphtashu Fitz]

I'm gonna call bullshit on this figure.

Keep in mind that you need to know the definition of a bug. It's not necessarially what you think it might be, but what the researchers defined. By their definition a condition that could never occur could be considered to be a bug. For example:

int foo ()
{
if (0)
return;

do_something();

return (0);
}

This overly-simple example could be considered to be a bug. If the condition is ever true the function will return an undefined value, but the condition will never be true so you couldn't possibly return an undefined value. It's not at all uncommon to find code with similar logic scattered throughout - improperly defined loops, conditionals, etc. could result in theoretical bugs that no path of execution can actually get to.

Then there are the kinds of bugs that only occur in extremly specific situations. About 13 years ago I had to track down a bug that caused a report package to crash. It took me a while to figure it out but eventually I did. The program would crash only on specific days. It'd only crash on Wednesdays. It'd only crash on certian Wednesdays - Wednesdays in September. Even more specifically, usually only the 3rd or 4th Wednesday in September.

The bug was that whoever wrote the code that printed a header on the reports was extremely anal about memory usage. He calculated exactly how many characters it would take for a buffer to hold the full date. The problem was he miscalculated by 1 character. With "Wednesday" being the longest day spelled out and "September" being the longest month, a 2 digit date (eg. Wednesday September 23) meant that the full date string would overflow the buffer by 1 character. This kind of bug wouldn't show up very often - only a few times a year - but it was a pretty nasty one when it did.