Some users have reported seeing low memory warnings when running Vibration.  The iPhone operating system sends warning messages to running applications when memory is running low.  Vibration warns the user if these memory warnings occur. 

Each window which is displayed receives this error message so you may find that you need to dismiss this message 4 separate times.  This will be fixed in the 1.2 release.

The lower memory warning is just that, a warning.  By the time these messages are shown the application is typically fully initialized and as long as the program is running there should not be a problem.  If memory becomes critically low the operating system will force the application to quit.  I have seen this happen on my iPod, typically when switching to the frequency display 

The iPhone operating system only allows one user program to run at a time but some Apple programs such as Safari do stay running in the background.  Also, some apps which have quit can leave a memory footprint, perhaps for quicker launches later.  If this memory is needed by another application the operating system will make it available, but this takes some time.  There is no CLEAR MEMORY button but you can use an App such as FreeMemory to free up some memory.  FreeMemory appears to do this by force quitting Safari.  In my experience this does free more than enough memory for Vibration to run with no warnings.  An alternate method is to shut down and restart your iPhone/iPod.

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This is a very good question and I do not know the answer.  When I have seen this error I have not noticed an affect on acquisition.  But if memory is low the operating system may need to swap information from RAM to non-volatile memory.  This could slow down data acquisition which will degrade the accuracy of the time base. 

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