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Salem is wrong - not all modern OSs use virtual memory

This is a discussion on Salem is wrong - not all modern OSs use virtual memory within the Linux Programming forums, part of the Platform Specific Boards category; http://cboard.cprogramming.com/linux...on-*alloc.html Compute Node Kernel, a linux kernel derivative that's used extensively on IBM Blue Gene supercomputers, and even on some ...

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    Salem is wrong - not all modern OSs use virtual memory

    http://cboard.cprogramming.com/linux...on-*alloc.html

    Compute Node Kernel, a linux kernel derivative that's used extensively on IBM Blue Gene supercomputers, and even on some Cray offerings, uses a kernel that does not offer virtual memory.

  2. #2
    Master Apprentice phantomotap's Avatar
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    O_o

    Wow. That is some necromancy you have...

    *shrug*

    Anyway, have you both understood what virtual memory is and understood the design papers for the relevant memory system? The "Compute Node Kernel" indeed does use some of the same techniques and hardware facilities as virtual memory. The most significant difference seems to be massive "pages" and the expectation of a "singular thread" allowing them to use the same while "bypassing" the need to support general purpose computing.

    Soma
    “Often out of periods of losing come the greatest strivings toward a new winning streak.” -- Fred Rogers
    “Salem Was Wrong!” -- Pedant Necromancer

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    What design paper have you read for the compute node kernel?

    Quote Originally Posted by phantomotap View Post
    O_o

    Wow. That is some necromancy you have...

    *shrug*

    Anyway, have you both understood what virtual memory is and understood the design papers for the relevant memory system? The "Compute Node Kernel" indeed does use some of the same techniques and hardware facilities as virtual memory. The most significant difference seems to be massive "pages" and the expectation of a "singular thread" allowing them to use the same while "bypassing" the need to support general purpose computing.

    Soma

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    I'm mostly amused by the fact that you went back more than 4 years, so you could post a thread that seems more about pointing out an error another member made, than anything else. There is no real content in your post discussing or asking questions about kernels that don't implement "traditional" VM systems, benefits, trade-offs, why they're used and in what circumstances, etc. If you had anything else to say, you failed miserably in doing so.

    Note that too, it's pretty typical (and reasonable) on this forum to assume "common" OSes -- things like Windows, Linux, Mac, many other flavors of Unix, BSD and hell, we get a frightening amount of DOS-era code on here too, and various embedded OSes. Salem's comment, though not explicitly stating so, was probably made under that assumption, though Salem would have to verify that, and I doubt even he remembers for certain, what his exact thought was when writing that response 4+ years ago. In a reasonable context of "all the modern OSes the OP of that thread is likely familiar with, use kernels with VM support". Most people who write for Crays and IBM super computers running CNK, Blue Gene or whatever, or are even somewhat acquainted with their internals, are probably not asking such fundamental questions on this forum.

    So if you have some real information to share, or questions to ask, then feel free. If you have some other purpose, I think you should state it so we know what this thread is really about.

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    Master Apprentice phantomotap's Avatar
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    If you have some other purpose, I think you should state it so we know what this thread is really about.
    O_o

    If this was just informative or a query you wouldn't need the "Salem is wrong" title; I'd be shocked if this was anything other than "shaming" for whatever reason.

    [Edit]
    Also, if any of you reading this is popular on the "social" web, could you try to make "#salemwaswrong" a thing?

    *giggle*

    I think I'm going to start using the phrase to curse all the lessor torments.

    Stub your toe? SALEM WAS WRONG!

    Run out of ketchup? SALEM WAS WRONG!

    Portable run out of juice?SALEM WAS WRONG!
    [/Edit]

    Soma
    Last edited by phantomotap; 02-10-2014 at 06:21 PM.
    “Often out of periods of losing come the greatest strivings toward a new winning streak.” -- Fred Rogers
    “Salem Was Wrong!” -- Pedant Necromancer

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    I actually stumbled upon this when looking up something about when pages are actually assigned to frames in Linux. I didn't actually go back because I remembered this discussion.

    "Note that too, it's pretty typical (and reasonable) on this forum to assume "common" OSes"

    That's not what Salem said, though. Salem said *all* modern OSs. He was trying to be a pedantic jerk (I feel like 99% of software engineers are like this), but he was actually wrong.

    "I think you should state it so we know what this thread is really about."

    Software engineers are pedantic jerks and Salem was acting like one while simultaneously giving out false information.

    Quote Originally Posted by anduril462 View Post
    I'm mostly amused by the fact that you went back more than 4 years, so you could post a thread that seems more about pointing out an error another member made, than anything else. There is no real content in your post discussing or asking questions about kernels that don't implement "traditional" VM systems, benefits, trade-offs, why they're used and in what circumstances, etc. If you had anything else to say, you failed miserably in doing so.

    Note that too, it's pretty typical (and reasonable) on this forum to assume "common" OSes -- things like Windows, Linux, Mac, many other flavors of Unix, BSD and hell, we get a frightening amount of DOS-era code on here too, and various embedded OSes. Salem's comment, though not explicitly stating so, was probably made under that assumption, though Salem would have to verify that, and I doubt even he remembers for certain, what his exact thought was when writing that response 4+ years ago. In a reasonable context of "all the modern OSes the OP of that thread is likely familiar with, use kernels with VM support". Most people who write for Crays and IBM super computers running CNK, Blue Gene or whatever, or are even somewhat acquainted with their internals, are probably not asking such fundamental questions on this forum.

    So if you have some real information to share, or questions to ask, then feel free. If you have some other purpose, I think you should state it so we know what this thread is really about.

  7. #7
    Master Apprentice phantomotap's Avatar
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    I didn't actually go back because I remembered this discussion.
    O_o

    -_-

    o_o

    -_-

    o_O

    Yog Sothoth!

    You "remembered" a post from 4 years ago because you took casual offense for no reason over an almost universal assumption?

    Trust me, this thread would be way less creepy and stupid if you had desperately searched the forum for a case of Salem being wrong about something.

    Soma
    “Often out of periods of losing come the greatest strivings toward a new winning streak.” -- Fred Rogers
    “Salem Was Wrong!” -- Pedant Necromancer

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    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by phantomotap View Post
    O_o

    -_-

    o_o

    -_-

    o_O

    Yog Sothoth!

    You "remembered" a post from 4 years ago because you took casual offense for no reason over an almost universal assumption?

    Trust me, this thread would be way less creepy and stupid if you had desperately searched the forum for a case of Salem being wrong about something.

    Soma
    I think he's saying that he found it just now via search, i.e., that he didn't remember it. (Given a join date of last year, he probably wouldn't have read it at the time.) I think (I would hate to be certain about it in this thread, for sure).

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    Master Apprentice phantomotap's Avatar
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    I think he's saying that he found it just now via search, i.e., that he didn't remember it.
    ^_^

    [Edit]
    You should have waited four years to tell me.
    [/Edit]

    SALEM WAS WRONG!

    *giggle*

    Soma
    Last edited by phantomotap; 02-10-2014 at 06:56 PM.
    “Often out of periods of losing come the greatest strivings toward a new winning streak.” -- Fred Rogers
    “Salem Was Wrong!” -- Pedant Necromancer

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    Kernel != OS.

    Tim S.
    "Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the universe trying to produce bigger and better idiots. So far, the Universe is winning." Rick Cook

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    Quote Originally Posted by gzhispanic View Post
    That's not what Salem said, though. Salem said *all* modern OSs. He was trying to be a pedantic jerk (I feel like 99% of software engineers are like this), but he was actually wrong.
    Welcome to that 99% then. You're being extremely pedantic in your reading of his post, and being a much bigger jerk about it. I get that he used "all", which is not technically correct, but I don't see anything particularly rude about his comments in that thread. If you want to argue a point, it is customary to support your argument with good logic (no fallacies) and proper evidence. The burden of proof lies with you in this case.

    Oh, and I find it absolutely amazing that you can read Salem's mind, especially 4 years after he had those thoughts. That you are actually able to ascertain the purpose of his comments in that thread was not to help the user, but "to be a pedantic jerk" is amazing (this is your use of "he was trying" that implies you know his motivation). If you truly had such a skill, WTF are you doing on this forum, you could make millions scheming the financial markets, gambling and more?

    Quote Originally Posted by gzhispanic View Post
    Software engineers are pedantic jerks and Salem was acting like one while simultaneously giving out false information.
    That first half is a blanket statement which (being pedantic) encompasses all software engineers, and is (again, being pedantic) in direct conflict with your "99%" comment. Surely not *all* of us are pedantic jerks. I doubt even 99% of us are. The second half, while objectively true, seems to imply again, that Salem's intent was to be rude and misinform, when it was more likely done for simplicity's sake (avoiding the corner cases for an OP who likely neither needs to know, nor cares about such things). However, his intention 4 years ago, is something none of us can know or even infer.

    And all this begs the question: if we're all such pedantic jerks (objectively, or subjectively from your point of view), why do you hang out with us? Why do you feel the need to come up to us and say we're pedantic jerks? That's a very jerk-like thing to do. Nice people would at least be polite in addressing would could have very well been an honest mistake/omission/imprecision. You just proved you're one of the people you seem to despise.

    Anyway, you don't appear to want to be in any way a positive, helpful, constructive, or otherwise useful member of this community, so feel free to remove yourself, and find someplace that will coddle your hypersensitive ego. Good luck in anything STEM related though, we're all pedantic jerks -- perhaps try the fine arts, or kindergarten.

    EDIT: Oh, and one more point of pedantry: if you want to whine, b*tch and rant, while providing no technical content, you should be on the "General Discussions" forum, there is nothing really Linux-related about your post.

    #salemwaswrong
    Last edited by anduril462; 02-10-2014 at 07:37 PM.
    phantomotap likes this.

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by gzhispanic
    That's not what Salem said, though. Salem said *all* modern OSs. He was trying to be a pedantic jerk (I feel like 99% of software engineers are like this), but he was actually wrong.
    Reading the thread that you linked to, Angus was not making some assertion that left open the question as to whether all modern operating systems use virtual memory, but rather seemed surprised that "calloc() does lazy allocation, in that it doesn't allocate any real memory, but just virtual memory". Therefore, Salem's reply dispels the notion that the use of virtual memory should be surprising. That reply certainly does not support your claim that Salem was "trying to be a pedantic jerk".

    Sometimes, someone states something is an old thread that is wrong, and nobody corrected him/her back then. If the thread was resolved based on that incorrect point, then it makes sense to post to correct it, even years later, if that correction matters. In this case, it doesn't. Salem could have easily written "most modern OS's allocate virtual memory" and it would have made no difference in the answer as long as the point made is equivalent to "do not be surprised as virtual memory is a commonly used technology". Hence, reviving that thread by making your statement would be poor form: let sleeping threads lie.

    If you still wanted to talk about the correction, then starting a new thread with a link to the old one like what you did here can make sense. However, the point would be to invite further discussion on the topic, not to prove a particular person wrong, and certainly not to state that:
    Quote Originally Posted by gzhispanic
    Software engineers are pedantic jerks and Salem was acting like one while simultaneously giving out false information.
    I think you need to learn how not to be a "pedantic jerk". Many of the regulars on this forum community are software engineers. Starting a thread specifically to insult them is... well, I will put the ball in your court: apologise now.
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    I find your post hilarious. You're clearly attempting to discredit someone who has a long and solid reputation of skill and knowledge about a craft. But the best you could come up with was to find an old, unrelated post, take the wording literally, and set out to find an obscure contradiction to what you perceive was stated.

    This is where the hilarity comes into play - if that's the "worst" offense you could find to back up your insult, then you're actually giving Salem a lot of credit, since you could not find an example with real substance to support your spiteful claim. You've achieved the opposite of what you've set out to do! Good job.

    By your reasoning, we shouldn't listen to anything that Stephen Hawking says since he was wrong about not being able to find the Higgs Boson particle.

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    Actually, I found this reference while searching for stuff on lazy allocation and calloc/malloc in Linux. I saw it, saw he made an incorrect statement *while simultaneously being pedantic* and had to point it out. If you want to try to be a pedantic little trivial software engineer from a 3rd tier university, you best make sure you are 100% correct.

    Quote Originally Posted by Matticus View Post
    I find your post hilarious. You're clearly attempting to discredit someone who has a long and solid reputation of skill and knowledge about a craft. But the best you could come up with was to find an old, unrelated post, take the wording literally, and set out to find an obscure contradiction to what you perceive was stated.

    This is where the hilarity comes into play - if that's the "worst" offense you could find to back up your insult, then you're actually giving Salem a lot of credit, since you could not find an example with real substance to support your spiteful claim. You've achieved the opposite of what you've set out to do! Good job.

    By your reasoning, we shouldn't listen to anything that Stephen Hawking says since he was wrong about not being able to find the Higgs Boson particle.

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    Quote Originally Posted by gzhispanic View Post
    Actually, I found this reference while searching for stuff on lazy allocation and calloc/malloc in Linux. I saw it, saw he made an incorrect statement *while simultaneously being pedantic* and had to point it out. If you want to try to be a pedantic little trivial software engineer from a 3rd tier university, you best make sure you are 100% correct.
    It's not that you pointed it out (and I fail to see why you "had" to), but how you chose to do so. Especially when your "argument" has little to no merit.

    I also find it strange that you are attacking people on the same forum that you've received helpful answers to your queries, based on reviewing your past threads. Laserlight gave you an opportunity to apologize for this, but it looks like that won't be happening.

    Anyhow, I'm not interested in engaging in a dialog with you. You're entitled to your opinions, and you're entitled to air them publicly. Anyone else is entitled to write you off as a childish prat and ignore you as they see fit.

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