[plist] Increase RAM with Dynamic_Pager (Virtual Memory) (iOS 4.1 Compatible!)

Use at your own risk!

What does Dynamic_Pager do?
- The iPod Touch 4G has 256MB of RAM and 8/32/64GB of Flash Memory depending on your model.
- Dynamic_Pager gives your device the ability to use Flash Memory as Random Access Memory (RAM, to an extent).

Are there any side effects to this?
- Its a fact that Flash Memory has a limited number of read/write cycles. The difference between Flash Memory and RAM is that Flash Memory has a lot less cycles available. Since RAM is written to a lot more frequently than Flash, and your Flash is being used as RAM, then using Virtual Memory will in theory reduce the life of your device.

- Virtual Memory was introduced to iOS a little more than a year ago, yet there hasn't been a single case of a device actually not working anymore due to using it. People usually say "VM broke my device, I had to restore to fix it", fact is if it really did kill your Flash memory, you wouldn't even be able to turn it on. Its said that the LCD would probably burn out or the battery would die before Flash memory would die on your device.

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- Previous versions of the plist would crash iOS 4.1, but I've gotten just the right settings to make it stable enough for public use. -

Installation:

There are two versions, a 256MB version and a 512MB version. This doesn't mean that your adding on 256 or 512 MB of RAM, and thats it. It just means each paging file will either be 256 or 512 MB EACH. If your using 256MB and background enough apps to fill it up, then a new paging file will be created. Its a matter of how intense you plan to multitask and spacial concerns.

1. Move the desired com.apple.dynamic_pager.plist from either the 256 or 512 folder, depending on what version you want, to "/System/Library/LaunchDaemons". Make sure permissions are set to 755 (use iFile).
2. Move com.apple.virtualMemory.plist to "/Library/Preferences". Make sure permissions are set to 755 (use iFile).
3. Change the permissions of /private/var/vm to 777 (Read Write Execute for all three) *VERY IMPORTANT*

Failure to not follow all steps completely can result in your device going into safe mode when activating VM

Usage:

1. When you have followed all the installation steps fully, reboot your device.
2. Open SBSettings once your device has fully rebooted and the SpringBoard is showing.
3. Open the Processes toggle and hit Free Memory to enable Virtual Memory

- Your device may become unresponsive during this time. It will take between 15 - 30 seconds to become responsive again. Once it does, you will see a drastic increase in available memory available, 180-200MB depending on what you have installed.

Tested on a 4th Generation iPod Touch, running Firmware version 4.1

Uh... even though I did post a version of this for iOS 3.x, on iOS 4.x, the way iOS handles memory is different, and will actually benefit more from less free RAM.

So to put it bluntly: this is unnecessary and will cause instability issues! Don't do it!

link to your post?

It is TRUE,never pass more than 10mb with previous versions(on 2.1.2,3.0,3.1.1,....)BUT LESS LIFE FOR DISK.SBsettings free process option is the best,arround 170mb free

It has another side effect. When memory goes low, either dynamic_pager tries to swap memory out to a swap file first, or the system sends low memory warnings to all running apps first, and the worst thing that can happen is an app tries to close itself while dynamic_pager is trying to swap its memory to a swap file. What do you think would happen then?

should i do this or not?

ok, SBSettings Free memory it is!

I tried the old version of this on my G4. the one I used on my 2G running 3.x - 4.0. and it gave me like 190 mb of free mem but messed up my device in so many ways.
If you type the "dynamic_pager" function into mobile terminal it creates a swapfile and you can select the size of it. I did it on my G4 but it doesnt seem to activate the dynamic_pager script, it just creates the swapfile.