swap/[vcache]

[socalgal]

first, apologies for posting in your thread, tommy67.

ok. I have been trying to figure out the best swap file/[vcache]sizes to set:

My sys: p200mmx, 80mgs RAM, 979mg hdd free.

Currently, swap set at: min/max - 120mgs

also, what would be the best [vcache] settings? One formula I saw was:

MaxFileCache: 25% of my ram, ergo: 80*25%=20; 20*1024=20480. isn't that alot?
and if that would be correct, what would be the minfilecache=

don't i want to keep both values the same in [vcache] (min/max)?

there seems to be alot of differing opinions on these 2 issues

arrghh somebody teach me heh


B.E. I tried to check out that link you posted in another thread, http://epsilon.silicon.net.my/adrian/ , I couldn't connect, will try later. maybe i will get some ideas from there

[This message has been edited by socalgal (edited 04-24-99).]

[Bleeding Edge]

Hey socalgal.

I just tried to connect to that link. Couldn't.

It's definitely a must-read. He covers all the questions people may have about optimizing the swap-file.

[Bleeding Edge]

Hey Hey.

Here's a C&P of the contents of this link. I had this page in my History:

Why Optimize The Swapfile?
A swapfile (or Virtual Memory) is important because often, the programs we use require more RAM than we have. Therefore, instead of returning an error message and refusing to run, the program can use the swapfile for the extra memory needed. This is because the swapfile acts as pseudo-RAM by using some of the hard disk space to store the data that would normally need to be stored in the RAM.

Using a swapfile may now sound like a really cheap way to run memory intensive programs without the expense of buying more RAM. However, even the fastest hard disk is at least an order of magnitude slower than the slowest RAM. And if you compare even the 10,000 rpm SCSI hard disk's bandwidth with today's PC100 SDRAM bandwidth, we will be talking like at least 50X slower. So, swapfile is only a stopgap solution for the lack of sufficient RAM. The ideal solution for insufficient RAM is always more RAM. But since we can't afford all the memory we want, a swapfile is necessary to allow us to run today's memory guzzling programs.

As you can tell, more isn't better for the swapfile because more swapfile space will only give you the ability to run more memory intensive programs at once. It will NOT speed up your system. But what we can do is to optimize the swapfile so that the performance degradation when using it is minimised.



How Do We Optimize The Swapfile?

There have been many theories on how to optimize the swapfile. The most important ones are listed below :-

Making the swapfile permanent
Moving the swapfile to the outer tracks of the hard disk
Creating a huge swapfile
Moving the swapfile to a different partition in the same hard disk
Moving the swapfile to a different hard disk
We will examine those methods and see what works and what doesn't.





Optimizing The Swapfile

Page 01 - Why Optimize The Swapfile?
How Do We Optimize The Swapfile?
Page 02 - Making The Swapfile Permanent
Page 03 - Writing And Rewriting To The Same Area =
Dangerous?
Writing And Rewriting To The Same Area = Good?
Page 04 - How Do We Create A Permanent Swapfile?
Page 05 - Moving The Swapfile To The Outer Tracks Of The
Hard Disk
Page 06 - How Do We Move The Swapfile To The Outer
Tracks?
Wanna Do It For Free?
Page 07 - Creating A Huge Swapfile
Why Not?
Page 08 - How Large Should The Swapfile Be?
Why Not 2.5 X System RAM?
How Much Virtual Memory Do I Need?
Page 09 - Moving The Swapfile To A Different Partition
Cylinders And Partitions
Need More Reasons?
More Partitions = Data Parachute?
Page 10 - Moving The Swapfile To A Different Hard Disk
Then How Do We Make It Work?
But...
Page 11 - What If I Still Want To Move The Swapfile?
Page 12 - Conclusion
A Word From The Expert
Page 13 - Comments
Page 14 - More Comments
Page 15 - Even More Comments
Page 16 - 4th Page Of Comments
Page 17 - 5th Page Of Comments

[socalgal]

Hi B.E. http://www.sysopt.com/forum/smile.gif

Yes - I have seen this article before and I remember being at that site, it was a good article and I used that method (this was also the one that recommends d/l NU3 to put the swap file at outer edge of disk. (too bad i didn't bookmark eh?)

Well, hopefully the site it still there, maybe there's a errant letter in the URL..

Since i do have a little bit of RAM here, i want to tweak my settings to get the best possible fine tune performance. You wouldn't happen to have p. 8 in your history, would you? lol

any recommendations on the [vcache]?

[Bleeding Edge]

All I have is this one page. Still can't connect. His conclusion on page 12 is to let Windows take care of it dynamically. This makes sense because there are some applications that require a very large value (300MB+ for some) and others that don't. This way we won't have to constantly resize it ourselves.

Win98 ability to page-out memory to disk, albeit not as well as NT, may be further hampered by manual settings. NT constantly writes memory that hasn't been accessed for awhile to the pagefile (swapfile). Freeing up that portion for further use. Only when that paged memory is once again called upon, will it place it back into RAM.

Keeping Win's dynamic setting helps in this process. One of the reasons MS strongly recommends leaving this setting alone.

I don't know if I'm missing something here, and I may be wrong, but I've always thought that vcache is the 32bit driver replacement (to manage memory) for the old 16bit SmartDrive and not an actual cache.

Have you installed the resource kit from the Win98 CD? I forget that I have it sometimes. Got to do a search on vcache. It's full of useful information -at times a bit technical.

[Bleeding Edge]

Okay. So there's a [vcache] heading in system.ini that has no entry. This initializes Win98's default setting for dynamically sizing the "internal cache," correct? So by Not entering a value, we let Win98 take care of it. By limiting the value, we can choose to have a set size, however, we can have a cache that is too large, which in turn, we are led by sources to believe that this may be the problem with Win98's dynamic setting; that at times it leaves the cache size too large or doesn't recover the memory afterwards. Hence your original question. How do we best optimize this. Okay. I think I got it.

Thanks.

It seems by the process of trying to understanded the question, it starts to answer itself. No?

If you haven't already.. homex.s1.net.sg/user/duane/b7000003.htm (http://homex.s1.net.sg/user/duane/b7000003.htm) ..Scroll down a bit.



[This message has been edited by Bleeding Edge (edited 04-25-99).]

[socalgal]

Thanks for that link.

re: chunk size. Is this a reference value to my external (L2) cache? If so, then it seems that i would want to set it to reflect my L2 which is 512. Yes?

It seems to me that you are suggesting to let windows manage everything - the swap (virtual memory) and the [vcache].

I thought there was a train of thought that this continuous back and forth unnecessary swapping not only decreases performance, but over time causes more defragging of the hd?

hmmm, those bios tweaks look interesting....

Thanks for your patience, time & effort Bleeding Edge! http://www.sysopt.com/forum/smile.gif



[This message has been edited by socalgal (edited 04-25-99).]

[socalgal]

Hi B.E. http://www.sysopt.com/forum/smile.gif
I read your reply with interest. You bring up some interesting points about letting Windows manage the virtual memory. I did a little research myself>

VCACHE
The disk cache system in Windows 95. VCACHE replaces the Smartdrive system used in older versions of Windows. Whereas SmartDrive is a 16-bit driver, VCACHE is a 32-bit driver. VCACHE can dynamically change the size of the disk cache depending on available disk space and application requirements.

disk cache
A portion of RAM used to speed up access to data on a disk. The RAM can be part of the disk drive itself (sometimes called a hard disk cache or buffer) or it can be general-purpose RAM in the computer that is reserved for use by the disk drive (sometimes called a soft disk cache). Hard disk caches are more effective, but they are also much more expensive, and therefore smaller. Nearly all modern disk drives include a small amount of internal cache.

Hmmm... I am assuming this means that manipulating the [vcache] is to utilize the 32-driver to change/set the disk cache (also called internal cache) RAM. If that value was too low for a certain application, enuf disk cache couldn't be accessed, probably causing a gpf/ipf.


I found another link re: swapfile/[vcache]. it seems to be a little old, and for win95, but the information seems solid enuf.

www.aserve.net/faq/win_95_swap.html (http://www.aserve.net/faq/win_95_swap.html)

i am going to try to find something that relates to win98, since that's what i am running. (and this time I am going to bookmark that site!)

AND.... how the heck did i miss that Reskit folder on my win98 install? I did a Find on the subfolders (tweakui, etc.) and sure enuf, i dont have them installed! DUH
I am going thru that win98 disk with a fine-toothed comb now LOL!


[This message has been edited by socalgal (edited 04-25-99).]