The virtual-memory tag has no wiki summary.
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In OS X vmmap output, what does it mean if a writable region has been written?
This is the vmmap line I'm referring to:
Writable regions: Total=451.9M written=242.0M(54%) resident=261.5M(58%) swapped_out=56.4M(12%) unallocated=190.4M(42%)
My broad question is "what does ...
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0answers
20 views
why do OS's sometimes disable caching for a memory mapped page in a page table?
I am reviewing notes for an OS exam and see that sometimes page tables have a disable caching bit, which is sometimes used in cases of memory mapped I/O. I get that memory mapped i/o takes some part ...
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2answers
67 views
OS X virtual memory size can't be correct, can it?
I've got Snow Leopard and 8G of RAM. Activity Monitor reports a VM size of 173 *Giga*bytes. My hard disk is only 250G and 200G of that is in use. I've got a lot more data than 27 GB on my hard ...
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3answers
98 views
On Windows 7, does it help to use two partitions on the hard drive for virtual memory page file?
I noticed we can set two hard drives or more for virtual memory page file. But my guess is, if it is the same hard drive, just two different partitions, then it may as well be just one partition? ...
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2answers
73 views
Atomic operation. How does it guarantee consistency from hardware perspective?
Atomic operation. How does it guarantee consistency from hardware perspective ? How is it implemented in HW ?
As far as I know, atomic instruction makes sure that when it is executed, no other ...
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2answers
127 views
What's the virtual memory address space limitation of a Win32 application?
Below is what I understand, please correct me if i'm wrong about the 3GB part?
a win32 application's virtual memory address space is limited by 4GB.
Of the 4GB memory address space each process ...
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1answer
70 views
Page pool and cache memory
It is subtly mentioned on this article, that the page- and non-page pool, are used for contiguous memory allocations which are sub-page size.
It then goes on to list the differences. I am not sure ...
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1answer
126 views
Virtual memory and commit charge
I've read a lot about commit charge and something still is bugging me. On my mac (and probably on linux too), what is the relation between VM size and and Commit memory (windows). I think I fully ...
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1answer
42 views
TLB access in SMT processors
In SMT (simultaneous multithreading) processors which threads share the TLB, how does TLB differentiate one thread's access from the other one? Each thread has its own set of pages loaded into memory, ...
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1answer
721 views
Is there an alternative memory allocator that uses separate swapfile?
Is there alternative allocator that can be LD_PRELOADed into a process, overrides "malloc", "calloc", etc. and allocates things using it's own swap files (mmaped to files instead of MAP_ANONYMOUS)?
I ...
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2answers
69 views
Virtual Memory is confusing me
My computer is like completely out of virtual memory. Granted I'm multitasking quite a bit, but I have 4gb of RAM which I just yesterday upgraded to from 2gb.
On the performance tab of task manager ...
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1answer
86 views
Will a swap file not slow down the system so much if a Solid State Drive is used?
Usually when RAM runs out, and a swap file is used, then the system can become really slow. But if the notebook or desktop is using SSD already, will a swap file be such a bad idea any more?
Can ...
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1answer
95 views
Does PF Delta include soft faults?
Task manager and Process Explorer from SysInternals are reporting ~3000 in the PF Delta column
While Resource Monitor only report ~5 Hard Faults / Sec
I've been told they are the same, so why they ...
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1answer
233 views
Virtual Memory and SSDs [closed]
Possible Duplicate:
Virtual Memory and SSD
On a Windows 7 system, isn't it more beneficial to leave the page file ON the SSD versus moving it over to a HDD? I've heard some say if you move ...
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3answers
127 views
Will allocating too much virtual memory have any negative effect on your laptop?
Like will it slow down your boot-up?
Also what problems will arise if you allocate more hard drive memory for virtual memory than what is available, will that cause any issues?
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4answers
1k views
Virtual Memory and SSD
While studying for the A+ Exam I was reading about SSD's and I thought to myself that if you had a mobo with a low RAM limit you could use a dedicated SSD purely for Virtual RAM. I looked up some ...
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1answer
96 views
Why do we need Virtual Memory? [closed]
I was reading about Virtual Memory and I came to know that it serves as a backup memory for the Main Memory. I am failing to understand the advantage. Why would you make a backup from a memory ...
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1answer
110 views
Is virtual memory related to virtual address space of a process?
I have understood that Paging is a memory management technique which allows computer to bring data from secondary storage to main memory for executing process. It gives an impression to process that ...
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1answer
51 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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1answer
184 views
Linux Virtual Memory/Swap isn't being used
I think my virtual memory is not configured correctly on my MintLinux machine. I opened up a new IDE, IntelliJ IDEA, and my whole system appeared to freeze. I tried to TTL to the console but that did ...
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2answers
228 views
What are the benefits of Virtual Memory?
So I've been reading up on virtual memory and it all seems pretty straight-forward and practical. However, I'm choking on one major concept.
If virtual memory is stored in main memory, then why even ...
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2answers
265 views
Why is my swap used even if my physical RAM isn't full?
Sometimes I have observed in Ubuntu's System Manager that without the physical RAM being used completely, the swap memory starts getting used.
Why is it so?
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2answers
132 views
Virtual memory vs. Virtual address space
I know virtual memory is a paging file that computer uses to store a part of RAM on hard disk for a running process. But how different is Virtual address space? is it the RAM or hard disk or both?
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3answers
164 views
Will increasing swap partition size increase the memory that can be used by a program?
I have a program that requires a lot of memory. So much that the malloc fails as the system goes out of memory.
I don't care if the overhead for swapping pages in and out of the disk is too high - I ...
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2answers
176 views
How did UNIX multitasking work without virtual memory? [closed]
How did UNIX multitasking work without virtual memory? Wouldn't applications still need their own memory space? Or did applications have to know that now all visible memory spaced is theirs?
(Note to ...
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2answers
2k views
what differences and relations are between logical and virtual memory?
I was wondering what differences and relations are between logical and virtual memory? How do their purposes differ?
Are the relations and differences the same for logical and virtual addresses?
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1answer
249 views
Windows 7 virtual memory size
I have computer with 4GB RAM running windows 7 64 bit edition. I have set paging file size 8000MB( both initial size and maximum size) according this document, but after restart I'm seeing only 4GB ...
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2answers
94 views
Is it true to say that once I quit a process, the RAM used is immediately reclaimed?
I'm running Windows Vista Home Premium SP2 32-bit.
Is it true to say that once I quit a process (Task Manager > Processes tab), the RAM used is immediately reclaimed?
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2answers
144 views
On Linux there is a 3GB/1GB kernel option. How do I do this in Windows 7 32-bit?
I have 4GB RAM installed. PAE is off. How do I tell the Windows 7 32-bit kernel to allocate 3GB virtual paging area to user mode and only 1GB to kernel space?
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1answer
21 views
Why Does my VM Keep Vanishing?
I have a Windows XP SP3 Professional OS running on a Dell Optiplex GX270. When I'm working with Visual Studio Express (a programming IDE), Google SketchUp, or any other resource-heavy program, my ...
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2answers
258 views
ulimit broke my server
I ran "ulimit -v 75" to get SBCL working, and now nothing will run on my server.
$ sbcl
Killed
$ vi
Killed
$ man ulimit
Killed
$ ulimit -v 256
-bash: ulimit: virtual memory: cannot modify limit: ...
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1answer
72 views
Is that true that Windows can eventually address executable files as if they were parts of virtual memory?
I've once read somewhere that Windows can treat programs' executables and DLL files as parts of swap file rather than duplicating their content into pagefile.sys when swapping them out of physical ...
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2answers
6k views
What are the dangers of manually setting IncreaseUserVA?
I run visual studio 2010 on a 32bit system and regularly run into issues with running out of virtual memory so I can no longer do things like copy / paste in VS.
I checked out a few options and the ...
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1answer
55 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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2answers
499 views
On Mac OS X how can I see how much memory is being used by what programs?
On Mac OS X how can I see how much memory is being used by what programs?
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2answers
346 views
Killing Windows 7 process which is using memory - look at Commit or Private?
I'm trying to clear up memory usage on my windows 7 with 2 GB RAM
Oracle.exe never shows up in the top processes, but the Resource Monitor shows it uses 637 Mb of commit (virtual memory) v 12Mb of ...
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1answer
93 views
What is Virtual Memory? [closed]
I would like to know what you guys think Virtual Memory is . Also Could you explain to me how the development of Virtual Memory has impacted operating systems and the personal computer.
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1answer
154 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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1answer
3k views
Need for page file with 12 GB RAM [closed]
Possible Duplicate:
Windows 7 pagefile size with large RAM and SSD
Hi,
I recently got my new PC with 12 GB RAM (running Windows 7 64bit). The default installation suggests a 12 GB page ...
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2answers
283 views
sizes of RAM, of virtual memory and of swap for 32-bit OS
If I understand correctly, a 32-bit OS (Ubuntu) can only address 4GiB memory, so RAM with size larger than 4Gib will only be used 4Gib of itself and the rest is a waste.
I am now confused about this ...
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4answers
2k views
Why is my browser using so much memory?
I've recently had problems with Firefox running very slowly when I have many tabs open; say 20 tabs. My whole system would slow down.
I decided to give Google Chrome a try, and it started out fine. ...
2
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1answer
183 views
How much virtual memory? [closed]
Possible Duplicate:
why do we need to set swap space as twice big as our physical memory?
I have been working on computers for quite some time now and realize the importance of virtual ...
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4answers
597 views
Force a process to run in virtual memory? Ubuntu
I am running a series of tests for an implementation of a remote pager that sends page faults to other computers in a network.
Long story short, I was wondering if there is an easy way to force a ...
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3answers
4k views
Can Windows 7 pagefile be turned off if 4GB of hi-speed RAM present? [closed]
Possible Duplicate:
Any reason not to disable the Windows pagefile given enough physical RAM?
I believe that there is enough of memory for everything used at the moment to be stored and ...
4
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1answer
172 views
Why RAM usage is much bigger than Virtual Memory usage
I am running some tests on a very powerful machine ( 24GB RAM, Window 2008 64bit )
I checked my task manager: Physical memory: 98% ( RAM is 24GB )
But the totally "Memory(Private working set)" usage ...
0
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1answer
486 views
System thinks it is swapping, but isn't
I have a linux server (Ubuntu 10.04) which has no swap space (swapon -l reports nothing, 0kb swap memory listed in /proc/meminfo). The beginning of the output of top (sorted by %mem) is reproduced ...
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1answer
2k views
Linux overcommit memory
I've been looking into memory overcommitting in Linux using /proc/sys/vm/overcommit_memory, and I've read a few articles which don't say the same thing.
This doc, under the heading "Going in the ...
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0answers
981 views
16GB RAM. Is it OK to turn off virtual memory? [closed]
Possible Duplicate:
Do I still need to use virtual memory?
I have a windows 7 64 bit machine with 16GB. Memory usage will never reach anywhere near that. Therefore I don't see why Windows ...
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1answer
329 views
Scheduled Task Priority and Paging problems
I just scheduled a task in my Windows 7, and I have 2 problems with it:
The process starting with Below Normal priority.
Even after manually changing the priority to Normal (via Task Manager), the ...
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3answers
562 views
Process Explorer not showing the biggest user of my RAM
Does anyone know why Process Explorer might show these weird values for memory usage of my Virtual Box instance?
Here are the real numbers:
But here's what Process Explorer is showing:
So the ...
