Virtual memory is a technique to provide more address space than the available physical memory. Each process can be given its own virtual memory, and the hardware translates every virtual memory reference to a physical memory address. To accommodate situations when more virtual memory is in use ...

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How big are copy on write pages in linux?

We used RHEL 5.8 at my office. Our program relies on fork for parallelism. The application is very memory hungry (up to hundreds of GB) so we're relying on copy-on-write functionality to make this ...
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193 views

High latency when writing big files. How to prevent more-than-second page faults when quickly filling up FS?

When I do cat /dev/zero > /some/file all processes tends to become slow (even non-IO related). latencytop shows "Page Faults" are more than 2 seconds. Swap is not used. Adjusting vm.dirty* does ...
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39 views

Is there a way to choose which applications go to virtual memory?

The way I understand virtual memory is that when an application is not being used for a period of time, the memory being used gets written to disk. When I use an application (netbeans), it seems to be ...
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81 views

Is CPU cache (L1 - Ln) equal to TLB

If we are talking about CPU cache. Is Ln synonym for saying 'TLB (translation lookaside buffer) of type Ln' or does Ln include also somethin else than just TLB?
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711 views

Virtual memory (caching) on Windows 8

I have read a bit about the issue, and I understood that the OS constantly pushes memory to the disk, so later, when another application needs a lot of RAM, it allocates that memory to it and "moves" ...
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2k views

Top command cache vs free memory

When I am running top command (on embedded system with 64 MB RAM) I am getting below description on total memory usage: "Mem: 43468K used, 968K free, 0K shrd, 1280K buff, 21896K cached" It looks ...
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102 views

Virtual memory paging

If the page size is 512 bytes and the paging table has 64 elements, each 11 bit. Howmany bits is the physical address then? - What does '11 bit' mean in this case? Is it the number of the frame (2^11) ...
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200 views

Mouse disconnecting and programs not closing and more

My mouse keeps disconnecting and reconnecting as well as my usb modem. My programs don't always close when i tell them to and even when I use task manager. T hey are also using all my RAM for a lot ...
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Seemingly inconsistent output from `top` re: Swap header vs. SWAP column

How should I interpret this seemingly inconsistent output from top re: swap? Running free confirms that no swap space is in use: $ free -m total used free shared ...
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What is the exact difference between the parameters (pgpgin, pswpin) and (pswpout, pgpgout) in /proc/vmstat?

Please note that this question is specific to linux only. And by swap space, I mean the dedicated swap partition. I did google a bit on this, and found these definitions: Paging refers to writing ...
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How can I see the correct “private bytes” value in process explorer?

I have a process that intentionally uses large amounts of memory. When I view this process in Process Explorer's list view with all memory-related columns enabled, this is what I see: Note that all ...
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115 views

Virtually Indexed Physically Tagged Cache

I have been going through the four types of data cache used in virtual memory, I came across this problem and I could not solve it. Consider a Virtual Memory system with 20-bit virtual byte address, ...
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Windows tells me there isn't enough memory and asks to close Firefox, but why this actually happens is unclear

My system has 4GB of physical memory, and a system managed paging file on an SSD. It seems like the paging file's size is capped to 12GB for a total of 16GB memory, which should be more than enough, ...
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7k views

Create a Virtual USB disk drive and connect it to Virtual Box

I have created a virtual USB removable disk using imdisk http://www.ltr-data.se/opencode.html/ using commands http://diddy.boot-land.net/firadisk/files/imdisk.htm but How I can mount it to Virtual ...
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365 views

improving swapping strategy

I'm finding linux's swapping strategy to be somewhat less than ideal. In general I have a ton of processes running, maybe 40 or more big ones, and only end up using a few regularly. Nonetheless, I ...
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241 views

swapping or trashing with vast amounts of unmapped pagecache

I'm using kubuntu jaunty (i386 32bit), kernel 2.6.28-13-generic. I've 4Gb of RAM, of which only 3317Mb are seen by the system (I guess because of the 32bit system). I'm seeing that the pagecache ...
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58 views

Application to Automatically Free Modified Memory

Is there a Windows application or script that can free modified memory belonging to a given application. I have tried Flush File Cache which is great as a big ol' hammer to clean out all modified ...
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Windows 7 connected to LCD monitor (using HDMI cable) reports low virtual memory if left idle too long

My Windows 7 laptop that is connected to my LCD monitor using an HDMI cable often reports low virtual memory if left idle for more than an hour or so - if it is left in that state long enough, the ...
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70 views

Win8.1 Bad Virtual Memory Managment?

For the last couple weeks I'm facing a serious problem with my Win 8.1 32bit (64x CPU) 4G RAM, having "System Managed size" setting for virtual memory (then win allocates 1.8G), minimizing even light ...
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22 views

Calculating average working set size

Say I want to calculate the average working set size (WSS) of this reference page string considering that the window size, delta = 3 : 1 2 310 (1 3)5 2 3 (2 4 1)10 5 5 1 1 1 2 2 5 (5 2)5 1 2 I ...
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125 views

Recommended paging file size formula

Is there a formula by which Windows calculates recommended paging file size? (see picture). This is definitely not 1,5 x RAM (this PC has 8 GB or RAM). I need to implement this calculation in my ...
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42 views

Cannot start site on IIS-Express

Some background: I Am developing a website that uses a BI layer that relays on Matlab. In order to make the logic layer available across my site I am creating it when the site starts (in ...
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101 views

Windows 8 will not boot after set virtual memory to 9999MB

To increase the performance of an ASUS X551M I increased the virtual memory 9999MB. In the past I would determine the max available virtual memory by typing in 9999. I expected to see something like ...
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16 views

Hardware support of windows 7

To accomplish the mapping of process memory, perhaps virtual, hardware support is often used. This is normally done via process base registers. The windows 7 operating system may also need base ...
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19 views

Why was overlaying suppose to be done by the programmer?

I was reading about OS memory organization, and the first entry in the Virtual Memory(VM) chapter refers to overlaying and how when it was used at a large scale (up to the 60s) the process memory ...
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virtual memory view in windows server 2008

AFAIK, Task Manager in windows 2008 shows the physical memory. I have a program that sums up the FREE physical & FREE virtual memory in MG. How can I confirm it has the right output of this sum? ...