Editing Performance requirements

'''Performance requirements''' determine if a system is actually used or not.  

''See also [[protocol requirements]], [[hardware requirements]], [[software requirements]].''

The [[Consumerium buying signal]] seems to have very tight timing requirements, and also must minimize [[visual distraction]].  If it is also [[handsfree]] i.e. via a [[headset]], that is also very important, as it might save seconds of fumbling, and enable use in situations where even a one-handed interface is of no use at all.  

Most [[breakthrough design]] happens by thinking hard about actual performance questions.  Some to consider:

*how long does it take to [[scan barcode]]s?  can this be reduced by use of [[RFID]] or [[NFC]]?

*how long can the user tolerate waiting to receive the [[Consumerium buying signal]]?  if they must have it at the [[retail shelf]] immediately, this is going to be difficult for even [[in-store radio]] to satisfy;  if they can wait until the [[checkout counter]], or a visit to a [[retail kiosk]], then a lot more possibile ways to deliver the signal exist;

*how long does it take to shift [[eye contact]] to a [[video]] display from what you are looking at, like the aisle or your children, and shift back?

*is there a risk that overt scanning of barcodes will attract unwelcome attention, e.g. from [[in-store security]], when not in a [[friendly retail]] location?  does this suggest using [[scanner ring]], [[RFID]] or [[audio]] only technology which is more innocuous?