Archived from groups: microsoft.public.windowsxp.general (
More info?)
Man! That's heavy! I'll have to put an ice pack on my brain and try reading
that again once it cools off a bit. Thanks a lot! I rally do appreciate
your thoughtfulness and help.
Ted Smith
"David Candy" <.> wrote in message
news:%233tQhVYkFHA.3580@TK2MSFTNGP09.phx.gbl...
Noone understands the depths of XP memory except the people who wrote the
memory manager, incl most MS programmers. To understand a little bit will
require hours of reading material where you don't understand a word. However
a lot of people understand a lot of the subject. But most people who talk
about are often wrong in part. It's a complex and not fully documented
subject.
He's an imperfect summation.
Their is virtual address space. Each process on your machine can address 4
GB of memory directly (and a lot more indirectly). There is virtual memory -
the sum total of memory - disk based and memory based. There is paging files
(up to 16 x 4 GB) and open exe files and other system files. Part of an open
executable becomes a swap file for that process (this is for speed reasons -
the data doesn't change so never needs to be written only read). All system
dlls are mapped into each process. So if you have a 1 meg system dll and
twenty processes then it uses only 1 mb of physical memory.
Programs reserve memory and can ask for more as well. TM doesn't show how
much of your paging file is being used but how much of your disk based
(paging files + open exe) virtual memory is being RESERVED. To see how much
is being used of the paging file type systeminfo in a command prompt. Mine
is usually around 40 MB which shows as around 150 to 200MB in TM's PF Used.
Available memory is not free memory, only memory available for use. It is
being used, partly by the system cache. Windows tries to keep free memory to
4 Mb I think (might even be 1).
Windows continuely tunes open apps. One thing it does is take a page of
memory (4k) off an application and see if it requests it by a page fault. If
not it adjusts it's working set down (the amount of physical memory a
process has). If you want to see what is the working set for a program look
in System Information (the GUI one) Software Environment\Running Tasks.
Windows tries to keep the physical memory to an app inbetween these figures
which it has determined by observation and experimentation is all it needs.
Remember that it does not mean the memory is written to disk if removed from
a program - it goes to available memory where it is written to disk if
needed, written to disk if the system is doing nothing but kept in memory as
well, or restored to the application if needed. Also only data is written
out (that is more than your data it includes the program's data like
variables) not code. As discussed above code is just dropped from memory and
reread from the exe. An exe contains code and data structures.
Task Manager's Help explain a lot of the terms. Use that rather than Windows
Help. System Monitor's Help you may also find useful.
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http://webdiary.smh.com.au/archives/_comment/001075.html
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"Ted Smith" <me@net.org.com> wrote in message
news:%23TZG7%23XkFHA.4024@TK2MSFTNGP10.phx.gbl...
> Thank you. I learned a lot from that web page, but I sure have a long way
> to go. One thing that was confusing was the mention of "free memory".
> My
> task manager does not show that expression. It does refer to "available"
> memory but I'm not sure that is the same thing. Maybe "free" memory is
> what's left of the "total" after you subtract the "available", and "system
> cache" amounts. Also, why aren't the "Kernal Memory" amounts included
> under
> "Physical Memory"? Aren't they all part of RAM? XP "Help" seems to be no
> help at all here. Do you know of a site that better (more simply)
> explains
> the relationships of the various numbers under Task Manager
> "Performance"??
> It sure would be appreciated.
>
> Ted Smith
>
>
> "Brian A." <gonefish'n@afarawaylake> wrote in message
> news:uleeL40jFHA.3336@TK2MSFTNGP10.phx.gbl...
>> See if this helps:
>>
http://www.aumha.org/win5/a/xpvm.htm
>>
>> --
>>
>> Brian A. Sesko { MS MVP_Shell/User }
>> Conflicts start where information lacks.
>> http://basconotw.mvps.org/
>>
>> Suggested posting do's/don'ts:
http://www.dts-l.org/goodpost.htm
>> How to ask a question:
http://support.microsoft.com/kb/555375
>>
>>
>>
>>
>> "Ted Smith" <me@net.org.com> wrote in message
>> news:uHVh6tzjFHA.2156@TK2MSFTNGP14.phx.gbl...
>>>I have 500 megs of RAM and each of my 6 logical drives indicate that the
>>>system has allocated 785 megs to the pagefile. That is huge. I can't
>>>imagine why any drive would need that much, and since I am runing out of
>>>space on some drives I would like to drastically reduce the size of the
>>>files - maybe to 300 megs. Would that be OK, or would it be unadvisable??
>>>
>>> Ted Smith
>>>
>>>
>>
>
>
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