Quote:
Originally Posted by FormerPalmOS
The pagepool is stored in RAM - the whole reason it exists is that you can't run code out of NAND flash storage - you have to copy it to RAM then execute it. If there ain't no room, you have to flush something out to make room. You can always copy it back in later. The amount of flushing and the corresponding performance hit while waiting to re-load something you need is why a bigger pagepool gives you better performance. Of course with a gimped VZW phone, if you have too big of a pagepool you don't have enough room to store the volitale data for whatever application you are running and it crashes. So it's a trade-off.
The physical location of the pagepool in memory doesn't matter - though I have no idea if it does or doesn't move.
Whatever is in the pagepool is lost at power-off. But it doesn't matter - everything in the pagepool got there by being copied from the flash anyway. The pagepool has a one way door. Stuff can be copied from NAND to the PP, but it is never written back - just scrapped.
The volitale data in the program memory (total RAM size minus pagepool size) must be written back to the NAND flash before power-off if it is to be saved.
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Exactly, but I think this discussion was about how static vs dynamic pagepool worked. Whether or not you could set the size of the dynamic pagepool as you do with static or if the OS simply allocated more to the dynamic as needed. I believe there were two camps of thinking as to how it worked and I was trying to rationalize how it would work assuming it worked the way gguruusa thought it did.
I suppose it could be that you can set the limit of your dynamic pagepool then the OS would use what it needed up to that point but I don't think that makes sense as it would quickly fill up to that limit. There's really no good reason that I can think of that it would work that way.
I agree with you that setting a static pagepool size would be like (in a PC) overriding the system defaults and fixing your pagefile size so that it's always the same size; never shrinking or growing. Assuming you still think this way, I think that a dynamic pagepool works more like your pagefile in a Windows OS; that it grows and shrinks as needed.
Before, when PPC's had less memory to work with I believe that you would have needed to set a static size. With today's devices that have much more memory to work with I'm thinking that setting dynamic might be the way to go...
BTW, haven't had a chance to check Tech Net yet. I'm too busy with product launches right now but I will dig into it as soon as I get the chance.