CE memory division between "storage" & "program" memory

re: CE memory division between "storage" & "program" memory

Zmaddi@matrox.com — Fri, 10 Sep 2004 18:14:00 GMT

Thank you Sue for all the info in this site, it is for sure very helpful!

Related to the answer of question "What is the minimum size for the program memory? How do I guarantee that my device can boot?"

Could you please tell me what kind of Win32 functions to use to have the minFree pages and total pages? Is OEMInit () a good place in the OAL to return the minimum RAM size to let the OS boot safely?

Thanks again

re: CE memory division between "storage" & "program" memory

Sue Loh — Fri, 10 Sep 2004 18:49:00 GMT

From an application you can use the read-only values UserKInfo[KINX_NUMPAGES] and UserKInfo[KINX_MINPAGEFREE] to find out the total number of pages and number of free pages. Inside the OAL you'd have to refer to them differently, I think KData.aInfo[]. I don't know what you mean about "returning" the size. Wait until you've gone all the way through boot -- long after OEMInit() -- before measuring the low-water mark.

re: CE memory division between "storage" & "program" memory

Zmaddi@matrox.com — Wed, 15 Sep 2004 01:07:00 GMT

Hi Sue,

I tried to use the KData.aInfo[] to get total number of pages & free pages inside the OAL but without sucess. I am only able to use the UserKInfo in application mode.

IN OAL: Since I am using pOEMCalcFSPages to recalculate the size of object store, can I use the value of dwMemPages (memory reported to kernel) as (minfree pages) + (min OS RAM) + (safety margin)?
So, that means my formula is:
(Object store ram) = (Total ram)- dwMemPages

thanks

How about auto adjust

Gordon — Wed, 22 Sep 2004 05:58:00 GMT

Thank you! Its very clear and helpful.
I found that while copy files to RAM file system and if there is no enough storage memeory, system will auto increase the size of storage memeory. But if there is no enough program memroy, no one to adjust.
Is it right?
Could you explain the auto adjustment?

Thanks!

Gordon

re: Zmaddi's question

Sue Loh — Fri, 24 Sep 2004 19:11:00 GMT

Zmaddi: The numbers I was suggesting were for figuring out, manually, what a good ballpark number might be. Not for figuring out programmatically during boot. For one thing, pOEMCalcFSPages is called far too early in boot for you to get a realistic approximation for how much memory is GOING to be used during boot. Reading the "minfree pages" value during pOEMCalcFSPages will almost certainly give you a bad representation of how much memory is going to be used during boot AFTER the pOEMCalcFSPages call.

My procedures were for if you wanted to choose a hard-coded size for the object store. If you want to calculate it programmatically during boot then the best I can suggest is: pick a hard-coded minimum, then if you want it to be more dynamic based on how much ram exists on the device, pick a percentage to use beyond the minimum.

re: Gordon's question

Sue Loh — Fri, 24 Sep 2004 19:17:00 GMT

Gordon: as I mention in the very last Q&A on the list, PocketPC is a completely different animal entirely because of the auto-adjust.

As I understand the PocketPC auto-adjust algorithm, it tries to keep the memory division such that the amount of unused object store matches the amount of unused program memory.

So, if there is no free storage available to convert to program memory, or if there is no free program memory available to convert to storage, then it cannot adjust to give you more.

Memory Problems FAQ

Daniel Moth — Wed, 12 Jan 2005 01:25:00 GMT

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