hello everybody!
What is this "push notification" and why does everybody want it so much? What does it really do?
Thanks for answering my dumb questions.
Normally the phone has to fetch data, aka the phone has to send a message to the server where the data is located (ie Yahoo server) and ask the server if there is any new data (ie emails), and then the server will tell the phone if there are or aren't, and you'll subsequently receive a notification on your phone. This means that unless your phone is fetching data every second (which it cannot do) you won't be getting data notifications immediately, so you won't get your email instantly. Example: I might send you an email at 9:00, but your phone might only fetch data 15 minutes later, and so you'll receive it at 9:15. The only reason this works is because the phone is designed to pull (or request) data from the server at specific intervals (which you can change in your iPhone settings). The problem with pulling data is it uses more battery life.
Some people need their emails immediately (and can't afford to keep an application running the whole time to receive said emails): enter push. Push is simply the server (ie the Yahoo server) pushing a notification directly to your phone to tell your phone that there is new data. The push happens as soon as there is new data on the server. So, as soon as I send you an email (to your Yahoo email account - as per the example) at 9:00, you'll receive a push notification from the server on your phone instantly, because the server tells the phone there is data as soon as it receives the email. So if I send the email at 9:00, you'll get it at 9:00. Push still uses battery life, but the idea here is that you only get pushed data (and thus use battery life) when there is something there - so presumably it's worth the battery usage to see the email, whereas if you were pulling data from the server you might check every 15 minutes but only receive an email during the fourth 15 minute pull of the day - thus 3/4ths of the pulls were worthless and wasted battery life.
That's push for email. The push that mostly everyone is talking about lately is the inter-application push notification service. Basically, if you have an application like Facebook on your iPhone, you want Facebook to push data notifications to your phone. So for instance, if someone was trying to chat with you on Facebook chat, even if you're not in the application, your phone would still receive a notification informing you that in the Facebook app someone is trying to chat with you. Same principle as email (in that it's an instant push from the server), but the idea here is that even if you're not using the application you'll still have notifications pushed to your phone. The problem with push notifications for applications is they'll destroy your battery life, so Apple has to figure out the best way to do it, and users are probably going to have to turn some applications push notifications off (either to save battery life, or because they'll be come rather annoying constantly serving you notifications all the time).
I hope that helps you out.
