Comparing Linux To System VR4

robyannetta writes "Paul Murphy from LinuxInsider.com asks the question What's the difference between Linux and System VR4? From the article: 'If there's a real bottom line here, the one thing I'm clear on is that I haven't found it yet, but the questions raised have been more interesting that the answers -- so more help would be welcomed.'"

Comments

What does this say?

[aluser]

There are several paragraphs in the article which, I think, don't actually say anything. Example:

Imagine, for example, trying to build a compiler able to produce an efficient executable in exactly one pass. Nobody does this now, for obvious design reasons consequent to an underlying sequential processing assumption, but it shouldn't be impossible. "All" it would take is a complete re-appraisal of everything we know about optimization and related issues in a truly concurrent, shared-everything, multi-threading environment with enough threads.

Am I completely out of my depth? What does threading have to do with efficient one-pass optimizing compilers? What's his issue with concurrency under linux anyway?
Or this:

On the other hand, this variation on the main question also raises new issues because many of the changes made to process and memory management between the 2.4 and 2.6 Linux kernels look a bit artificial -- meaning that they don't seem to be direct continuations of code evolution up to 2.4 and thus raise the suspicion that the SCO/IBM lawsuit might be having some unexpected design consequences.

What makes a patch "artificial" ? Whatever that means, how does it imply anything about the sco/ibm lawsuit? Weren't the 2.5 development line split and the major scheduler changes introduced before the lawsuit? Even if not, what would he consider a continuation of the development up to 2.4? In short, can somebody explain to me what this guy is saying?

Re:RTFA

[Bruce Perens]

He's not interested in data either. The article's a troll, with almost zero real technical content.

Bruce

WARNING: BACKGROUND AHEAD

[Anonymous Coward]

The author of TFA thinks that SCO has a case. Hopefully, that should alert you all which corner this guy is in. I've tried reasoning with him over e-mail, but:

• He would not respond to my argument that there is BSD code in UNIX.
• He thinks SCO has a case, but their lawyers are doing a bad job of explaining it.
• He thinks IBM's lawyers are in cahoots with Groklaw to make SCO look bad

Just for grins, I will now debunk TFA:

• "Imagine, for example, trying to build a compiler able to produce an efficient executable in exactly one pass. Nobody does this now" - Except TCC.
• "raises new issues because many of the changes made to process and memory management between the 2.4 and 2.6 Linux kernels look a bit artificial" - Bold claims (and no reference) for someone who claims to be ignorant. But historically, a large fraction of Linux gets re-written between major versions anyway. Compare V2.0 and V2.2 or V2.2 to V2.4. I dare you!
• "which kernel would better illustrate the implementation ideas? [..] the right answer here is System VR4, mainly because it's almost equally portable but simpler and clearer." - It also performs terribly. An O(1) scheduler will look messier than an O(n) scheduler. Hmm, MINIX is even simpler and clearer still.. Hey, I see where this is going!
• "Compare Microport's AT&T Unix port [..] in 1992 to CDE running under Linux 2.4 [..] today and there are enormous practical differences, but few conceptual ones." - Maybe because they both stick to the POSIX API? Look at it the other way: Windows XP is conceptually the same as Windows 3.1. You just send messages and handle events, right?
• "they didn't come from the Minix/SysV foundation." - Aha! Here he is red-handed implying that Linux was "founded" on Minix/SysV. Go read Groklaw you SCO shill.