iOS4 on iPhone 3GS

[NickFitz]

Just upgraded the phone. Took about fifteen minutes to download and install once I'd got iTunes 9.2.

First impressions: very nice

I've spent an hour organising all my apps into folders, and am now down from nine screens to two. The folder thing is easy to use: just hold down an app icon for a second to go into "jiggle mode". When you drag an app onto another one, it creates a folder containing them and works out from the nature of the apps what a suitable title might be, although you can edit it then or later if you choose.

iBooks for iPhone seems OK with a few Project Gutenberg freebies.

Fast app switching (double-click the home button) works. Not a lot else to be said.

Mail threading seems to work, which is handy when most of your mail is from mailing lists. Dunno why they didn't have it before

The map view in the Photos app seems OK; however, I don't often take photos with my phone so it won't be of tremendous value to me

The first backup after the upgrade took longer than usual, so I assume it isn't an incremental one due to a change in file formats or something. I expect later backups to be quicker. That aside, syncing seems to be much faster.

I dropped a couple of PDS onto iTunes and they appeared in the new "Books" tab for the phone. Both were fine to read in iBooks, including a password-protected one. Hyperlinks (from the table of contents) within that book also worked OK.

I haven't got a Bluetooth keyboard, so I can't test that.

The spell checker now offers multiple suggestions when you tap a red-underlined word, which I don't think it did before.

Spotlight search has a nicer interface than before, and offers the option to search the web or Wikipedia instead (at the bottom of the list of results).

That's about all I've had a chance to play with so far, but generally speaking it's looking like a very good upgrade

Now, over to a bunch of people who go on about something their Nokia 666 could do in 1843, without realising that not only was it not the same thing, it also didn't work.

[DimPrawn]

Can you downgrade back again?

[DiscoStu]

Think I'll wait for the jailbreak to be released before I upgrade

[Moscow Mule]

Doesn't do much shiny on the 3g. Folders are ok but not multitasking.

Due an upgrade in September so will get one then.

[nodric]

Has anyone noticed the max volume on iPod playback being lower? i.e. When I used to blast my music to drown out all the Bobs around me, I had to turn it down a notch from max. Now max is not loud enough.

Other than that, everything seems to work well Just waiting for those multi-tasking app upgrades now. Just wish you could decide whether to close an app, rather than them all automatically being suspended and left on the multi-tasking taskbar. It's going to become a very long slider if you never kill any of the tasks

[Durbs]

Spoke to somone today whose 3G runs like a dog after the upgrade and several apps no longer work. Mine works ok though which is what matters.

Played with a 4G today. Mmmmmmmmmmmm, shiny, that screen is unbelievably good and it was rapid to use and felt lovely in the hand. Video and photo was also top-notch. Getting one next week.

We tried the holding the bottom left corner thing and the signal does indeed drop a couple of bars but i can live with that. He said it wasn't an issue for him as his hands naturally didn't go there anyway.

[Moscow Mule]

It's going to become a very long slider if you never kill any of the tasks

You can kill them from the taskbar, chap at work with a 3gs was showing me the other day.

[nodric]

You can kill them from the taskbar, chap at work with a 3gs was showing me the other day.

Yes you can indeed, by holding an icon until they jiggle, and then hitting the no entry mini icon.

Problem is, this gets to be a pain in the ar*e. Would be better that all apps didn't default to multi-tasking. i.e. When you hit the home key to exit an app, it could prompt to say, keep active yes/no?

The idea of multi-tasking is to switch back to an open app to resume where you left off if you don’t want to loose your place when you have to take a call, or check a note etc. However, you don't need to have that option for every app you ever opened since you upgraded to 4.0

I've so far had around 25 apps paused! There must also be some energy consumption issue, especially when all apps become multi-tasking capable. If they all stay paused by default, dragging some juice from the battery to maintain there last active state, then its life is bound to be shorter than if they had been closed.

Imagine you open Maps, you then forget to kill it on the task switcher. It continues to update your position, sucking the life out of your phone, as will any other position aware apps! Going to be a nightmare remembering to kill all those apps by holding down the icon, scanning along all those jiggling icons, and then killing off the right ones.

[NickFitz]

Yes you can indeed, by holding an icon until they jiggle, and then hitting the no entry mini icon.

Problem is, this gets to be a pain in the ar*e. Would be better that all apps didn't default to multi-tasking. i.e. When you hit the home key to exit an app, it could prompt to say, keep active yes/no?

The idea of multi-tasking is to switch back to an open app to resume where you left off if you don’t want to loose your place when you have to take a call, or check a note etc. However, you don't need to have that option for every app you ever opened since you upgraded to 4.0

I've so far had around 25 apps paused! There must also be some energy consumption issue, especially when all apps become multi-tasking capable. If they all stay paused by default, dragging some juice from the battery to maintain there last active state, then its life is bound to be shorter than if they had been closed.

Imagine you open Maps, you then forget to kill it on the task switcher. It continues to update your position, sucking the life out of your phone, as will any other position aware apps! Going to be a nightmare remembering to kill all those apps by holding down the icon, scanning along all those jiggling icons, and then killing off the right ones.

It's not a problem. When an app is in the background it doesn't use any power as it isn't running, unless it's written specifically to use location services, stream audio, or VOIP. In those cases, it should only be running a background task if the user has explicitly requested it: when a VOIP call ends it stops, when you stop playing streaming audio it stops, when you haven't asked the app to keep track of your location it doesn't. (For example, Maps doesn't keep track of your position while in the background, so you needn't worry about that.) These are among the requirements enforced by Apple before an app can get into the App Store: if an app doesn't conform, it will be rejected.

As far as memory is concerned, an app will be allowed to remain in memory but will automatically be purged by the OS if the memory is needed by the foreground app. Apps have to be written to cope with this by persisting their state. The app delegate methods for coping with this are the same as in version 3, so existing apps continue to work correctly.

The basic flow is that, when you switch to another app, the running app is notified that it's going to be sent to the background. Assuming it doesn't have any ongoing background activity, it persists its state (probably in the database via CoreData, although other approaches are possible) and goes to sleep. If it's still in memory when you switch back to it, it's told that it's only waking up again and so it can fire up again quickly, as its in-memory state will be the same as when it went to the background. If it has been purged, it is reloaded and notified that it's coming back up from being terminated, so it can then restore its state from wherever it persisted it to.

Existing apps shouldn't have a problem with this, as the only new thing is the business of potentially transitioning to a background state and back again: the terminating-and-restarting process is what apps did on previous versions. Also, any app that tries to keep on going when its sent to the background (other than via the appropriate techniques for the cases listed above) will be detected by the system and terminated with extreme prejudice. As such an app should never make it into the App Store, this shouldn't be something you see though.

Overall, having had a thorough read of the developer docs, Apple did an excellent job of implementing this. You really don't need to worry about there being a bunch of apps in the background, as the majority of them will in fact be doing nothing, and probably aren't even in memory at all. In that sense, the apps chooser can be seen as a quick way of getting back to recently-used apps; it may be that the app you go back to happens to also still be in memory and gets back up and running very fast, but you as a user don't have to know about that, so you aren't told.

FWIW, the relevant rules and recommendations in the Apple docs are:

Applications that support multitasking in iPhone OS 4 and later should do the following:

• (Required) Respond appropriately to the state transitions that occur while running under multitasking. Applications need to observe these transitions in order to save state and tailor their behavior for foreground or background execution. Not handling these transitions properly could lead to data loss or improper behavior. For more information about the states and transitions, see “Understanding an Application’s States and Transitions.”
  
  
• (Required) Follow the guidelines for behavior when moving to the background. These guidelines are there to help your application behave correctly while in the background and in situations where your application might need to be terminated. For information about these guidelines, see “Being a Responsible, Multitasking-Aware Application.”
  
  
• (Recommended) Register for any notifications that report system changes your application needs. The system queues notifications while an application is suspended and delivers them once the application resumes execution so that it can make a smooth transition back to execution. For more information, see “Responding to System Changes While in the Background.”
  
  
• (Optional) If you want to do actual work while in the background, you need to request permission to continue running. For more information about the types of work you can perform, and how to request permission to do that work, see “Executing Code in the Background.”

If you do not want to support multitasking at all, you can opt out and elect to always have your application terminated and purged from memory at quit time. For information on how to do this, see “Opting Out of Background Execution.”

[scooterscot]

Just installed 4 on my 3gs, feels smoother and faster than the previous firmware