running directly from RAM on wince?

Noel J. Bergman noel at devtech.com
Mon May 28 05:26:22 UTC 2001


>> Build for Win32, and test on your PC.  These are not WinCE
>> specific APIs. :-)
> In theory yes, but in practice ...

In practice, they work just fine in the PC Emulator, where I tend to do all
of my first round testing for PocketPC.  I didn't mean to give any
impression that he could or should run them native on WinMe or Win2K.

You won't see important device performance differences in the emulator.  For
example, the cost to page in a 1K page on the iPAQ is approximately 0.2
milliseconds when the memory mapped file is located in the internal object
store, and approximately 1 millisecond when the file is located on a CF II
solid state storage card.  You won't see any of that in the PC Emulator.

Also, iterating through memory in byte order is 6 to 7 times faster on the
iPAQ than iterating over the same region of memory in page order.

Both of which imply that co-locality is really important to performance on
the iPAQ.

>> Shall we keep this between you, Ohshima-san, Ned and I until we get it
>> working?  Just so as not to swamp the list.  I don't know if
>> everyone wants to follow the birthing pains.

> Please keep me in the loop - I've got a bit of experience with
> that kind of stuff.

Absolutely!  Just didn't want to bore everyone with the birthing pains.  But
anyone who WANTS to see/help ...

	--- Noel





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