Made these two changes....

1. I manually changed my virtual memory from letting Windows do it. I read where you want the minimum to be 1 1/2X and the maximum 2X your RAM....is this correct and will it do any harm?

2. Under system properties/device manager/HDD/properties/ settings I tried to enable or check the DMA box. I checked it and then restarted this thing, but going back there shows it is NOT checked. What happened, and if I can change that, is it harmful?

 

Depends on the age of your setup. In the old days they say setting your own at 1 1/2 to 2 times your memory improved things. Best to let Windows do it now. If it's not DMA capable, when you restart the Enable DMA option will remain unchecked.

 

devildog#4

If you have a few minutes grab a coffee and pop over to here.

The author has a good style and isn't shy at getting his hands dirty unlike some 'tips' sites which shamelessly plagiarize others and make no effort to test the validity of such often propagating nonesense.

While your'e at it he considers, in the same style, the Disk Cache here and the cache's chunksize here.

The boys and girls at MS were in fine fettle when they took Win95's memory management to task and created the Win98 version.

In theory an increased chunk size seemed a winner if we have the Ram to accomodate but, it seems, in practice the option is a dead duck.

 

This depends on your available disk space and if you have more than one partition.

If you have a D: HD partition and room on it. Set the swap file to 300 or 400meg minimum with no set max.

Then if you do have Norton Utilities use SpeedDisk and let it put the swap file at the front of the partition and then forget it.

This assures that Windows always has room for the swap file.

It is ALWAys in the same place and Windows does not have to go looking for room.

Cuts down the fragmentation of the C: drive considerabley.

And better yet. If you have a HD on the other IDE controller but the swap file on it.

What has RAM got to do with the swap file ( virtual memory ) Swap file involves HD space not RAM.

BillyBob

 

Chunk size may be confused with cluster size. Disk cache chunks are analogous to HD clusters. Chunk size was first mentioned above in the line starting "While your'e at it he considers, in the same style,... "

Virtual memory = Swap file + Physical memory ... (1)

When an app asks for memory it is allocated virtual memory by the Virtual Memory Manager. The app never knows, and doesn't need to know, how that virtual memory is comprised ie what is swap and what is physical.

In my case Swapfile Usage is invariably zero so (1), in practice, reduces to:-

Virtual memory = Physical memory

 

Now that is a switch around from what I have been thinking.

Or we done got ourselves a different understanding of how things work.

If an app needs memory I thought it went to the PHYSICAL memory first.

Then if there was not enough available it would go to the Virtual memory ( swap file/virutal memory ) Or SWAP something out of Physical Memory to Virtual Memory and then back later. Why else would it be called a SWAP FILE ?

The more Physical Memory requires less Virtual Memory ( swap file ).

And how can physical memory and virtual memory be considered the same ?

Phisical Memory is HARDWARE. A piece of material with a bunch of chips on it which in inserted into a slot on the Motherboard.

Virtual Memory ( swap fle ) is not. The total amount of Virtual memory can be user controled. The TOTAL phsysical memory is constant unless the user changes physical hardware by adding/removing or changing hardware chips.

The amount of Phsysical Memory available depends on how much the users has loaded into it. The less sutff loaded at boot up leaves more physical memory available.

Physical Memory + Virtual Memory = Total Memory.

But how much is available for use depends on what the users has loaded and/or running.

BillyBob

 

I'd just about finished the following when Christer posted.

My understanding is got from research papers on memory management but this thread is not the place for such links - devildog#4's profile is 'Beginner' which is why I steered him toward the posted links; not exactly light reading but certainly not heavy.

"If an app needs memory I thought it went to the PHYSICAL memory first. "

The app doesn't do anything except put its hand up and say "Can I have some memory, please ". The VMM responds and it is it that determines how the virtual memory is provided with regard to Ram pages and Disk pages (whence Page file aka Swap file). This process is transparent to the memory requesting application and it has no idea if data is held in Ram or the HD.

"And how can physical memory and virtual memory be considered the same ?" We wouldn't consider them the same because they aren't. Applications, on the other hand, don't indulge in such considerations because they aren't aware of a difference.

"Physical Memory + Virtual Memory = Total Memory. "

This is true only if Virtual Memory is synonomous with the the Swap/Page file.

Microsoft's interpretation of virtual memory is "Memory that appears to an application to be larger and more uniform than it is." MS also use Virtual memory synonomously with the Swap file and also use the phrase "Virtual memory swap file ". The latter is more accurate and allows the unused phrase "Virtual memory Ram ".

We have then:

Virtual memory = Swap file + Physical memory

and I see that Christer's understanding endorses this.

 

Swap file, Virtual Memory, Page file. Are not physical memory.

Windows may use them in a certain way. Or even combine them. But they are different things.

Also it may be depend on which version of Windows is being used. Each version may do things a liitle different.

It is a certain amount of space on the HD that either Windows can be allowed to allocate ( depending on its needs ) or the user can allocate ( reserve ) a certain amount of space and in a location of user choice.

I myself prefer to reserve the space. Then Windows ain't gotta spend time looking for more room if it needs it

But again the amount of Virtual Memory can be controled by the user if he decides to do so.

That´s why TM reads a higher value than NSD

I do not, never have and never will go by the numbers. They only refelect what is happening at that moment. I go 100% by how the OVERALL usage of the machine goes. If I have to make changes and loose a little here but gain a little there then that is what I do.

All the books do is to give a BASIC knowledge of what is SUPPOSED to happen. But they do not tell us how the recommeded settings will behave on our machine. Hardware ( from the MB on up ) and software can very much determine how we set things.

Christer may be able to take the same programs A & B that I use and have to set things up differently in order for them to work properly on his machine. He may have tossed program C: into the mix and caused him to maybe make change to those changes.

I find if I set thing up so that I get the best preformance from Links Golf 2003 when playing over the Intenet that the REST of the system responses very nicely also. I believe that is because the system is then set meet the requirements of the heaviest system taxing program that I have.

And Links 2001 that my Wife and I play between two machines is even behaving much better since I did that.

And I also find that by having a permanent set size swap file Golf behaves much better.

BillyBob

 

This is probably getting too esoteric for the starter of this thread. Reading my first post's links is enough to be going on with for the time being so I'll say no more.

 

Somebody wants me to read books OK I will.

Edited quote from the first link gammaepsilon listed.

That is the way that I always figured ( or understood how ) it worked.

The virtual memory abstraction is implemented by using secondary storage to augment the processor's main memory.

I will not argue with that a all. But I believe the key word in the above is (secondary)

I have a hunch ( in other words I am not sure ) that programs will run from virtual memory ( swap file ).

Don't they have to be in RAM ( Physical memory ) to run ?

BTW. Unless I am wrong Virtual Memory can be wiped out and rebuilt on a system shutdown/startup.

BillyBob

 

HUH OH !!!

This should read.

" I have a hunch ( in other words I am not sure ) that programs will NOT run from virtual memory ( swap file ). "

BB

 

I cannot sit and read this.

You are both wrong.

Storage is storage is storage.

Programs are not run from storage no more than data is manipulated in storage. Storage is for depositing executable code and data. Both have to be fetched and presented to the CPU with its registers, arithmetic units, floating point units and so on.

Primary, secondary - these are just words. What's a rewritable CD Rom? Tertiary? Zip drives? Floppies? All just storage.

Take a tree with its rings. This is a natural data base of the trees history. Take an optical reader to gather than information. What do we get? A read only wooden hard drive. Its not virtual memory because we cannot write to it; at least in the same way the data/rings were created.

The CPU hasn't the foggiest idea where the code or data came from - whether that be Ram, a hard drive or a tree.

Of course the whole shooting match works via the caches. L1, L2, Disk cache and so on. The Disk cache, caches info from the hard drive. The Ram cache, caches info from Ram. Ram cache? Yes, that's the hard drive.

The only difference is the access speed of our storage.

An app may ask for data stored on 50 pages. One day that data may be in the form 40 HD pages and 10 Ram pages. Another day that data may be in the form 15 HD pages and 35 Ram pages. The app never knows where the data is coming from any more than the CPU does. Neither need to know.

We can complicate the picture by saying things like 'With Win95 apps cannot run from the disk cache, they have to be moved into free physical memory, whereas with Win98 apps can be run from the disk cache.' This is to do with memory management and not running programs.

 

That my freind is WAY, WAY WAY, out line and completely uncalled for.

This post is not about who is right or wrong.

It is about our differences in interpeting some printed words some where.

And I did to. And from one that was pointed to by at poster.

BillyBob

 

If I or anybody;

1--Was really wrong in our understanding of what does what.

2-- Was really wrong by setting our machines up according to those understandings.

3--10. We sure would not need any person telling us so. Our machines would be 10 jumps ahead of them with a nice white on blue message saying to the effect " YOU MESSED UP. "

11-20. We would be asking for a lot more HELP instead of just more or less discussing different views of something and how it works.

21-30. Or in the worst case be typing FORMAT C: and starting over.

31-100. We are all right in setting our machine up the way they work best for us.

BillyBob