iOS 4 Multitasking: The great power drain
Now we know why Steve Jobs procrastinated so long over introducing multi-tasking, however limited. Yesterday, Day One of my iOS4 installation, I set out along the River Thames path for my usual constitutional. Ten minutes from home I was accosted by a BlackBerry waving guy who couldn't find a particularly desirable pub somewhere ahead. I hadn't heard of it, and I didn't know where it was. However, I knew an app that can and soon had TomTom up and working on the iPhone.
Off went a contented BlackBerry man (soon, I suspect, to become iPhone man after such a fluent demonstration) and I pressed the home button before stuffing the phone into my pocket. Twenty minutes later I approached by own favourite pub, the Old Ship, with a cappuccino in mind. On opening the iPhone, though, I got a power shock. The battery was already down to 65% and I'd done nothing since leaving home - except, of course, helping BlackBerry man on his way.
Yes, you've guessed already. The culprit was multitasking. But I realised I hadn't a clue how to find out which apps were running because I had not read (nor even heard of) any instructions. I soon recalled things I'd read on various blogs and remembered the swift double-click on the home button. This brought up the list of running (or, more accurately, standby) applications. I'd managed to get no fewer than six in the list, despite not having done anything much.
TomTom had pride of place on the left of the list and I realised it must have been beavering away with the GPS all the time I'd been walking. But how to stop an app? Here, again, I had to use my intuition and I soon discovered that by holding down TomTom I could get all the running apps to grow a red minus icon. Even then I was a bit wary, because this is very similar to the way in which you delete apps. Of course, as I soon discovered, you just press to minus icon to remove an app from memory.
Following this, battery drainage returned to near normal. I also took the opportunity to switch off Notifications in Settings, although I am not sure if this has any effect on battery usage.
So, a lesson has been well learned. TomTom is a battery hog at the best of times. Even when the phone is sitting in the car cradle and connected to the power socket, the power input can barely keep pace with the demands of TomTom and, at the end of a journey, the battery state is usually exactly the same as it was at the beginning. Without external power, TomTom can drain your battery big time. If you leave it in memory by mistake, perhaps when leaving your car, you could be in for a shock.