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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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Your choice!
I still don't see any references to anything countering my position yet. You said at least one of the articles I linked to is counter to what I've said - please, quote which part. I'm inviting you to prove me wrong, and even provided links, but all you ever post back is "you're wrong", but never substantiate it?? Does that have anything to do with the fact you can't prove me wrong, because it would actually undermine your position? I think the phrase I'm looking for here is "I've got you on the run". Best regards, Vulcan. |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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define "drop" define "backed pages" and provide links to technical descriptions that substantiate your definitions from Microsoft please. Best regards, Vulcan. |
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Magic Man
Chief Pilot Joined: 02 Apr 2008 Location: South Wales Points: 5336 |
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"drop" as in drop from ram, release from memory etc. etc. "backed pages" as said, stuff that already exists as physical files on the drive as opposed to unbacked stuff, i.e. memory pages that have changed, user changed stuff etc. that exist only in RAM (unless you have a page file)
No, irrelevant. They are just words.
Nope. The links you've provided have been mostly irrelevant to the issue here which is your insistence that running without a page file is better than with. You have yet to prove your case or provide relevant links that agree with this... Little snippet. Granted, not a tech net article nor anything more than advice but from the horses mouth at least...
Why would they say that if, actually, you get better performance by doing the opposite?
So are you saying that your whole argument that the page file is not required and better performance is gained by switching it off is based on the experimental condition that we have unlimited memory...? Really, surely you are not serious...? Your whole issue is that it is better to run without a paging file than with it, we don't have the fantastical gift of "unlimited memory space" unfortunately. None of your extensive posted links have even mildly pointed in that direction let alone prove it so rather than asking me and the others here following the advice of the designers, developers and experts who are actually responsible for the page file, its use by the memory manager and Windows as a whole, to prove why it's better to leave it there, give us your reasons why those people are wrong...
Ha, in your dreams... |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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OK...
OK, to ensure there is no confusion on my part: If I have a block of data from hard disk loaded into the memory address at 0x00FE457 for 10 bytes to 0x00FE461 and then the system freed the memory to load something else, instead of copying this block of memory to the swap file, it simply "forgets" it, and overwrites this 10 byte block of memory with something else, and just loads the 10 bytes it just overwrote, off the hard disk again, should it require it? Am I understanding this correctly? Best regards, Vulcan. |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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You might be interested in this:
http://www.ece.cmu.edu/~ece548/handouts/05vmarch.pdf Just to highlight it before you do:
A swap device (typically a disk) that holds pages not resident in physical memory (that’s why it’s referred to as backing store as well) See the difference? I've personally never seen it referenced as a "backing store", but hey-ho - like I said, it's just terminology. HOWEVER... You will note that NOWHERE in these notes does it say it drops data that *already* resides on the hard disk in the traditional sense of a program or user data. All it does (and as I said it did), is it copies physical memory locations to the hard disk. Nothing more, nothing less. You can write and argue with Prof. Philip Koopman if you like. You can find his contact details on the Carnegie Mellon University website. Best regards, Vulcan. |
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MartinW
Moderator in Command Joined: 31 Mar 2008 Location: United Kingdom Points: 26722 |
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Why would they say that if, actually, you get better performance by doing the opposite?
So why would they Pointy? Or are you saying Microsoft, the very designers of the OS are idiots and you know better? Or are Microsoft conspiring against us? Sorry to be on the opposing camp, [I’m hardly qualified to be on either] but this just looks like you thinking you know better than the experts again, and in this instance the experts that actually coded the thing. It's there product, wouldn't they know better than you? Bet you don't answer. At the end of the day, It's YOU that’s making the controversial claim, it's YOU disagreeing with the designers in regard to their own software, so it's YOU not Magic Man that must prove YOUR point, not him.
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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I don't see performance being cited as a reson to keep it. It just says not to disable it.
The reason not to disable is because if you have 128 Mb of RAM and tried to run FS, without a page file, FS would not even start as it would run out of memory. @Marmite: see why I said it was important to discuss the page file and performance from the point of view of UNLIMITED memory??? Best regards, Vulcan. |
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Marmite
Chief Pilot Joined: 11 Apr 2008 Points: 1029 |
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That link just proves the point you argue against - "Components that make virtual memory work... A swap device" So therefore disabling a page file means there is no swap device, ergo screwing over the functionality of virtual memory since it has nowhere to store swapped pages. Edit: You posted while I was typing, memory cannot be "unlimited", you can probably theorise that but in the end it's a physical impossibility. The more memory you have the more computers will use that available memory |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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You see the word VIRTUAL? Do you need a dictionary?
Of course disabling the swap file will affected VIRTUAL memory. Sheesh. Virtual memory is but one small part of the overall scheme of memory management. You need to read the more general notes on memory management to understand this. Best regards, Vulcan. |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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I know that in reality it is impossible, but when discussing the benefits of disabling the swap file, by assuming unlimited memory, and the fact that the system will swap memory out ANYWAY despite having lots of spare memory (unlimited in our example) then obviously it has performance BENEFITS. At the other extreme end of the scale is a system with 16 Mb of RAM running Windows XP. The system will be positively living out of the swap file, yes???? Best regards, Vulcan. |
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Marmite
Chief Pilot Joined: 11 Apr 2008 Points: 1029 |
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Which in turn affects physical memory.
http://support.microsoft.com/kb/555223 As I've said before, I'd rather leave paging turned on, at least it gives the OS something to fallback on if I run out of physical memory. |
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Marmite
Chief Pilot Joined: 11 Apr 2008 Points: 1029 |
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Sure if you have unlimited memory in that sense then you would see an improvement since you wouldn't be writing to the slower hard drives, however you'd still run out of memory eventually |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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Yes, if you run out of physical memory. If you have plenty of physical memory, then disabling the swap file is not a problem. Further, it increases performance because like it or not, even if there is free physical memory (several hundred megabytes) Windows will still copy memory to the swap file!!! The result of this is if the system then tries to access memory that was swapped out, even if it is for 10 bytes, it has to make disk I/O and performance instantly suffers.
Only if you were stupid to try and run the system to the limits and beyond. Memory is so cheap there is no excuse not to add more physical RAM if you regularly run out of physical memory (swap file enabled or not). You WILL see increased performance for doing so. It is best to have more memory than you will use (hence my choice to go for 4 Gb for Vista for example - I know I won't use more than this at the current time. If I do, I'll simply buy more RAM). Some limitations: 32-bit OS can never ever address more than 4Gb of memory. Because of memory mapped I/O present in current computer systems that you or I run, this limit is further decreased (in my case, to 2.6 Gb as the rest of the upper address lines are used for addressing hardware, etc. and are unavailable for memory addressing). The page file can not exceed 4096 Mb in size, and XP x86 will never acknowledge more than 4 Gb of physical memory. Here is a question: if you have two page files, both 4096 Mb in size, will Windows use them up to the full 8 Gb available? From your link: http://support.microsoft.com/kb/555223 Let me clarify one important point: Virtual memory is NOT the page file. It has nothing to do with it. Best regards, Vulcan. |
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Marmite
Chief Pilot Joined: 11 Apr 2008 Points: 1029 |
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The page file size limit for 32bit Windows (with PAE enabled, which most XP are by default) is 16TB.
I'd rather leave my paging turned on, than risk BSODs and system crashes over a slight possible performance increase (not that I've seen any figures that prove such an increase exists). |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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That's stupid. You'd have to have 4096 page files to make use of that!!!
Best regards, Vulcan. |
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Marmite
Chief Pilot Joined: 11 Apr 2008 Points: 1029 |
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Figure came from a technet article http://technet.microsoft.com/en-us/magazine/2007.04.desktopfiles.aspx
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Magic Man
Chief Pilot Joined: 02 Apr 2008 Location: South Wales Points: 5336 |
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If the memory manager decides to release memory pages occupied by code that is backed, i.e. .exe’s, .dll’s, etc., stuff that already exists on the disk, then yes it is just freed, unless the page has changed, there is no need to copy it to a page file (why would it need to, it already exists). When that page is required again it is simply paged back in, i.e. re-read from the file on disk, i.e. from the .exe, .dll etc.
Absolutely astounding logic there... “Well Mr President, the reason I pushed the big red button with ‘Do not push’ printed on it was because it didn’t say it would cause any harm...”
Winner of the grand prize in the ultimate copout competition 2009. Explanation of theory by reference to an unobtainable quantity, brilliant!
Your whole point was that you have disabled your page file because it is beneficial, not because in a hypothetical situation with unlimited memory. You haven't got unlimited memory. It's irrelevant anyway since if you did have unlimited memory then the mm would never need to page out unbacked store to the page file anyway so it wouldn't be used. Turning it off would gain nothing other than recover the small amount of drive space - and in this hypothetical world of unlimited memory then surely we have unlimited drive space as well so why bother?...
You do not have plenty of physical memory. 4GB was enormous and certainly more than plenty in most cases a few years ago, now it’s average. The more we have the more we use, you can never really have plenty...
Reducing the memory managers options does not increase performance. The page file will only be used if the memory manager needs to use it, if it needs to use it then you need a page file. Without it you are limiting its options.
And disk space is even cheaper. There is absolutely no excuse not to use a page file if you regularly run out of physical memory, buying extra RAM is a second option limited by funds and, if you are running a 32bit OS, limited by the addressable range. As said, 4GB is not that large. Go with it by all means, I have 4GB in my main box, but why then not give yourself the additional use of a page file for the mm to use if it requires it?
On a 32bit OS a single page file is ‘limited’ by that size by default. It can be made larger as Marmite noted. You can also have additional page files on distinct drives (I have one on each of my two drives). You can also have multiple page files on the same drive (different directories) with a registry edit.
It will use them as it sees fit. It will choose which to use based on I/O metrics for best performance.
Thanks for that, wasn’t in question. “Nothing to do with it” is a but extreme though, they are obviously related. |
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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No it isn't. Not at all. Please refer back to my link to the slides from the Carnagie Mellon University website. As I demonstrated when I deleted the FS9.exe file - the file was no longer on disk for this behavior to work. If this is how it did work, deleting the FS9.exe file should have created chaos, regardless of whether the swap file existed or not. As should be clearly apparent to you by now, no reference is ever kept of which file data came from. The system doesn't know, and it doesn't care. All it does when it writes to the page file to clear some physical memory, is copy the memory location verbatim. That's it. What occurs to files on disk, it doesn't care. Again, please study the link very carefully. You have a flawed understanding. Best regards, Vulcan. |
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Magic Man
Chief Pilot Joined: 02 Apr 2008 Location: South Wales Points: 5336 |
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[pantomime audience]Oh yes it is…[/pantomime audience]
What exactly did you demonstrate and conclude from this and how is this trying to prove your case that a page file isn't needed...? Loading it and then removing the physical file is only going to cause a problem if the situation arises that the virtual memory manager decides to drop memory pages relating to FS9.exe and then tries to page them back in. Actually, since the file no longer exists I’m not sure if the pager will even permit those code pages to be released or, if a pagefile is present, whether it instead uses it for backing store of the pages moved out.
Rubbish. Unbacked pages will have no physical reference because they don’t exist on disk. Backed pages will have since their pages are paged in from the .exe, .dll file etc. It obviously knows where it came from. Or are you saying that all memory pages that are paged out go to the pagefile? If so then that is wrong and if so then where are you without a pagefile since in your world you would never be able to page anything out. You've already correctly said that paging still occurs without a page file, in your world how can it if "All it does when it writes to the page file to clear some physical memory, is copy the memory location verbatim"...?
You have a flawed understanding (sorry, left the quotes off that...)
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VulcanB2
Chief Pilot Joined: 02 Apr 2008 Points: 13365 |
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The point I am making, and you don't understand, is that the system does not care if the file is on disk or not. It has no bearing on memory and whether the system will try to page it out or not. Clearly you're never going to understand this.
Huh? Read my links again. Keep reading until you understand. I'm finished here. Best regards, Vulcan. |
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