[madphone]

...and I know that this has been brought up.

But my question is if we have 128MB of application memory that can be used for the OS and any 3rd party apps why does the "free space fluctuate?

For instance on my MeterBerry App, it says:
Application
Total 128.0 MB
Free (19%) 24.1 MB
Since Start Up -10.9 MB

The available space and size of the applications does not change why does the amount of space available change? According to MeterBerry App, these are directly related.

If I have 128.0MB of space for applications and OS then I should have a constant amount available, right? Thinking of my PC, I have a 500GB hard drive and 4GB RAM. When the PC is using more ram it does not change the available space on the hard drive, right?

Forgive me, I am not a true techie but I truly want to understand this better than I do. Thanks to those that attempt to answer this.

[my_2_cents]

Well, the biggest reason is that some programs are written with "leaks" they grow a little bit with temporary information that they generate as they are used. Log files etc.

There are also the other programs you use that generate or download information, for instance the browser and messages. If you use VIIGO, it downloads news articles etc. These all have to be saved in that app memory, unfortunately they can't be saved elsewhere yet.

All of those little things add up over time to eat away memory. When you restart the BB, all those temporary files are deleted, which brings your memory back up to about what it was before. Any differences are for files that remain such as cookies, Viigo stories etc.

Some programs are written with horrible memory leaks. I've been seeing quite a bit of a memory leak with Viigo so far. I believe it is just that the more the program is designed to do, the less efficient it is with memory use. Viigo is designed to do a massive number of things, the programmers couldn't be expected to get it all perfectly, especially in Beta.

[ntffl07]

Is there an application out there that shows what apps are leaking and how much they leak?

[Morf32]

Is there an application out there that shows what apps are leaking and how much they leak?

Not one that will specifically peg a certain app for a leak. The programs that are out will help you tell that there IS a memory leak, but not which app is causing it. The only way to tell which specific app it is would be to delete them one by one until the leak goes away... then you have found the specific app causing the leak.

[Giant Cashew]

The answer to your question can be found in the MeterBerry FAQ:

Q: What exactly is "application memory"? How does it relate to the other memory on the Storm?

A: The Blackberry Storm has 1 GB of internal flash, or device memory. 128 MB of that flash is allocated as application space, the other 872 MB is allocated as data space. The Storm also has 192 MB of traditional RAM. These memory spaces are used as follows:

1. When they are running, the Operating System (OS) and applications both use the 192 MB of traditional RAM like your computer does. Temporary, volatile storage.

2. All applications are stored in the application space. Whatever room is free in the application space is used by the OS for paging when your phone is running, similar to what your computer does with its hard drive and swap file. Applications can only be stored and run from the application space.

3. The data space is used for an internal file system, as well as storage of things like pictures, ring tones, etc. You cannot store and run applications from the data space.

When you go to Options -> Memory, the "Application Memory" entry refers to the free space in the application block of the internal flash.

So, when you install applications the free space in the application block decreases. And because the application block is also used for paging, the free space fluctuates over time as you use your phone.

RIM most likely doesn't display the free RAM under Options -> Memory is because the RAM is used by the OS in addition to applications. It wildly fluctuates up and down as the phone is running, and doesn't give you any real measure of what's going on. But if an application has a true memory leak as is described above, you would be able to detect it by looking at the free application memory. And of course your free application memory also tells you how much room you have left for applications.