If Apple changes to a 4-inch screen in the next iPhone (iPhone 5,1), how could they do it while minimizing impact on users and developers? Assuming everyone wants a bigger screen, how does Apple implement it without breaking existing applications, causing backwards compatibility problems, and otherwise fragmenting the platform and frustrating stakeholders? Let's try to figure that out.

For a while now we've been hearing that Apple hadn't yet decided on the next iPhone design, and that while they were then working off the same 3.5-inch size are previous generations, they were still considering increasing the screen size up to 4-inches (but no more than that).

Earlier today both The Wall Street Journal and Reuters published stories saying Apple was going ahead with a 4-inch iPhone screen, but didn't provide any details as to how a 4 inch screen would be implemented. And those details are arguably even more important than the screen size itself.

That's because change has ramifications. Every choice has a cost. When you're dealing with millimeters and milliamps and megabits-per-second, everything is a compromise.

If Apple has indeed chosen to go with a 4 inch screen, there are only so many choices they can make, compromises they can reach, and ramifications that can be handled, developers, and Apple itself.

Scaling the current iPhone screen up to 4-inches

Apple can simply take the current 960x640, 326ppi, 2:3, 3.5-inch display and physically scale it up to 4 inches. The pixel density would drop to 288ppi, which would be substantially less, but would still be more than the new iPad's 264ppi display. (And would still be higher than the new iPad display -- so hold that as close as you hold your iPhone and see how it holds up.)

The result of this type of screen would be bigger text, bigger controls and buttons, bigger touch targets -- in other words, bigger apps. There would be no extra pixels gained, so the amount of information that could be displayed wouldn't change, but the same amount of information would be displayed at a larger, presumably easier to consumer, easier to interact with size. Only at a lower density.

If the iPhone screen is simply stretched to 4-inches but the resolution stays the same, the physical size of icons, text, and everything else just gets bigger.

Does that matter?

Apple has invested heavily in the "Retina display" marketing concept. Retina, however, is a function of density over distance -- the further away you hold the screen, the lower the density needed for pixels to effectively disappear. Apple could, even tenuously, argue a bigger screen would be held slightly further away, resulting in little net loss of "Retina-ness". (They did that at the new iPad event, after all).

Put it all together and users get the advantages of a bigger screen, developers get the advantage of keeping a consistent screen resolution target, and Apple gets the advantage of not substantially disturbing or disrupting either of those groups. For these reasons, if Apple does go with the a 4-inch screen, this seems to me to be the most likely path they'll take to get there.

Scaling the current iPhone screen to 4-inches, pixel doubling it (again)

Apple could take the current 960x640, 326ppi, 2:3, 3.5-inch display and scale it up to 4 inches, and once again double the pixel count to 1920x1280. That pixel density would explode to 579ppi, which... is frankly insane.

Never mind how expensive that kind of panel would be, or how hard it would be to achieve usable yield rates, it's overkill. It would enjoy the same benefits as a physically larger display, but maintain Retina display -- even for a falcon.

But as Georgia pointed out on the podcast earlier, that panel would also cost battery power to light it up and graphics power to push that many pixels around.

Unless Apple wants to increase screen size substantially beyond 4-inches, and screen, battery, and mobile GPU technology advances while prices fall and yield rates shoot through the roof, this seems extremely unlikely.

Scaling the current iPhone screen to 4-inches, changing the aspect ratio

Apple could take the current 960x640, 326ppi, 2:3, 3.5-inch display but change the aspect ratio to something closer to 9:5 and increase the height to 4 inches by adding pixels. The resolution would increase to 1152x640, and the pixel density would remain the same. (It's just adding extra pixels to the top and bottom.)

Timothy Collins brought this up on The Verge and John Gruber of Daring Fireball pointed a giant spotlight on it. iLounge later added to this particular rumor pile.

Since pixel size remains the same, text size would remain the same, control/button size would remain the same, and touch target size would remain the same. Apps that use the built-in interface elements would simply add an extra row of information -- an extra row of icons, an extra row to the table or item to the list. The display would be vertically larger, and more information could be displayed on it. But what about apps that don't use built-in UI elements?

Safari would show more of a page's length, Mail would show an extra message, but games and anything with a highly customized, non-table based interface would have to be pillar-boxed. If developers made new versions that fill the extra space, those versions would be cut off on older iPhones. And if developers made 2 versions of the apps, it would mean more work for them and "fatter" binaries for users to download. (A universal app would go from having iPhone and iPad interface elements, to having old iPhone and new iPhone and iPad interfaces.)

While many things are possible, this doesn't seem like a very Apple-esque solution. It would fragment the iPhone platform for developers in a way Apple has resisted so far, and offer incomplete user benefits (increasing pixel count in only one direction).

More importantly, it would mean either significantly redesigning (or eliminating) the Home button, or lengthening the iPhone casing, or a bit of both. iMore has heard the Home button isn't going anywhere, and parts leaks have suggested it looks pretty much the same, so that leaves a longer iPhone and that... would be awkward. (Even if you remove part of the bezel to make room for it.)

Scaling the current iPhone to 4-inches, increasing the number of pixels

Apple could take the current 960x640, 326ppi, 2:3, 3.5-inch display and increase both the width and height to 4 inches by adding pixels. The resolution would increase to 1092x728 (or thereabouts), and the pixel density would remain the same. (It's just adding extra pixels all sides.)

As above, text, control/button, and touch target size would all remain the same, because the pixel density would remain the same. Apps that use the built-in interfaces could also add an extra vertical row of icons or list or row information, and could add extra "white" space in many cases, or vertical columns in some cases, to fill in those extra pixels.

While the user gets more information, unlike the vertical-only extension, splitting the extra pixels both ways means neither have enough room for an extra row or column of icons at the same pixel size. Safari would show a more of a page in both length and width, but Mail might not squeeze in an entire extra message, or that much more message contents. And now games and anything with a highly customized, non-table based interface would have to be completely boxed, the way iPhone apps are on the higher pixel count iPad display, or stretched to fit, which would look horrible.

If the screen gets more pixels, older apps would have to be boxed on the new iPhone the same way iPhone apps are boxed on the iPad. (Letter and pillar.)

If developers make new versions that fill the extra space, those versions would be cut off on older iPhones, or scaled down to fit that would likewise look horrible. (As I've discussed previously.)

So even more work for developers, maybe an @1.14x physical size, and still "fatter" binaries for users to download.

Automagic scaling, like some platforms promise with sliding components, is as mythical in design as "write-once-deploy-everywhere" is in programming. Lazy developers or incredibly programmatic app implementations might default to it, but pixel perfect designers are going to want pixel level control over every screen size and density.

That makes this solution just as unlikely as the last. Even if Apple takes the (now) unusual step of canceling previous generation iPhones when the new one launches, and abandoning their current lower price point strategy, there would still be hundreds of millions of 480x320/960x640 iPhones and iPod touches on the market, and developers would want their apps to run on that massive install base.

increase both the width and height to 4 inches by adding pixels. The resolution would increase to 1092x728 (or thereabouts), and the pixel density would remain the same. (It's just adding extra pixels all sides.)

Switching to 720p resolution

Apple could take the current 960x640, 326ppi, 2:3, 3.5-inch display and simply swap it out for a standard resolution screen like 1280x720, at 16:9.

There are Android Devices that use this screen, but so far they can't be made any smaller/denser than 4.3 inches (see the HTC Rezound). Does Apple might have the tech muscle to drive that resolution down to 4 inches any time soon?

The pixel count would be able to show more information horizontally and vertically, and it would be a Retina display and then some at 367 ppi. If icons and text stay the same pixel count, then the presentation would be smaller. If the physical size stays the same, pixel count has to increase.

That's what happens when you changing so many parameters at once -- physical size, pixel count, aspect ratio -- it has both the benefits and the problems of everything else already listed above.

A 720p, 16:9 display at 4-inches would both shrink existing app UI elements and touch targets, and require an even larger letter and pillar box.

Apple would need a third new interface size, existing apps would be boxed, and new apps would need to be cropped or scaled on older devices, resulting in a horrible experience and appearance. That makes this option seem the least likely of the bunch.

Switching to original iPad screen

Apple could take the current 960x640, 326ppi, 2:3, 3.5-inch display and simply swap it out for a much smaller version of the 1024x768, 4:3 iPad display. This would peg the density at 320 ppi.

Other than it being the same resolution as the original iPad and iPad 2, there's not much different about this option than the 2:3 1092x728 or the 16:9 1280x720. It has the same benefits and drawbacks as both the previous options.

The argument that it would let iPad apps run on the iPhone is problematic, however, as iPad apps have controls/buttons and touch targets designed for a much larger physical size and if you think shaving fingers down for a 7-inch version of the iPad is a challenge, reducing them to the needlepoints necessary for what would essentially be a 4-inch version of the iPad is even more so.

Under the "let iPhones be iPhones" motto, this doesn't seem likely either.

Something else

Apple could have some other way to handle a 4-inch screen, or combination of ways. Point of fact, Apple already knows what they're planning to do (if they're planning to do it), or at least which methods they're testing. That doesn't diminish the mental exercise of trying to divine it before Apple announces it, but it does put it in context.

If Apple goes with a 4-inch screen -- and until Tim Cook or Phil Schiller holds it up on stage, or it somehow leaks conclusively, a 4-inch screen remains an if -- these are just some possibilities.

And all of them have ramifications, opportunity costs, and compromises. Some simply more than others.

Additional resources

• iOS 6 wants: Files app and documents picker with iCloud
• iOS 6 wants: The opposite of widgets
• iOS 6: Is it time for Apple to revamp the Home screen?
• The challenge of bringing Siri to the iPad
• iOS 6 and privacy: How Apple should draw inspiration from Android for better app

148apps posted up a PR from a developer in the Czech Republic that states:

“When the Push based application such as NotifyMe requests an ID from APNS, the server responds within a second and identifies the device with the unique token. From that point, the connection between APNS and user’s device is successfully established,” said Pavel Serbajlo, PoweryBase’s lead developer. “However, on a unofficially activated device, APNS keeps the application wait forever and does not provide any respond at all, keeping user wait infinitely or time out the connection, if the target application is capable of timing out.”

Last week we mentioned Jailbreak users were having problems with Push, but a lot of you responded that things seemed just fine, or that an updated Jailbreak process fixed it for you.

So that makes us wonder, is Push Notification really not working? And if it's not, is Apple really blocking it, or is it just not set up to recognize some Jailbroken iPhones that weren't activated in the usual way via iTunes?

Since the iPhone 3.0 Jailbreak has become available, and now with both purplera1n and redsn0w coming on line with iPhone 3GS Jailbreak solutions, we've heard rumblings about problems with Push Notifications not working, or not working properly.

The Dev Team has noted this:

we have some remaining 3.0 jailbreak issues to investigate, including push notification

danmowchan in our forums notes this again today with regards to Prowl. Potential battery drain issues aside, if you've Jailbroken, are you having trouble getting your Push on? If not, has problems with Push made you put your Jailbreak on hold?

If you're anything like us, the moment iPhone 3.0 hit iTunes, you hit the update button. For many, it was smooth sailing from that point on. For others...?

Not so much. We're hearing about several issues, from disconnecting Wi-Fi in 2nd Gen iPod touches (hello BT radio!) to missing apps, to sync issues, to push problems, to seach nulls, to my own little bizarre issue:

All my media is fine on my iPhone, but when I plug it in to iTunes, it's read as gigabytes of "other" data and I get a helpful message saying my iPhone is already full.

Of course, the nu-cu-lar option is always a clean restore, but if you want to troubleshoot first, check out TiPb's iPhone Forums. Our users are among the smartest in iPhone -- and iPod touch --space, and with our cracker-jack mod team in place, we can all help each other to... help each other.

I noticed 3 messages stuck in my Gmail outbox post-OS 2.2 upgrade. Just sitting there. Mocking me. "Sending" but never getting "sent". Following a comment by Matt, I re-typed my password and voila, the intertubes they were cleared.

Not sure if this will work for everyone, either by itself or with a reset, but give it a try and let us know.

UPDATE: scottb helps out earnie in the comments with a Google link for unlocking display Captcha to overcome an invalid sender address problem. Our readers rock!

Any other trouble-shooting tips? Keep 'em coming!

So you are having issues with your iPhone? Maybe you jailbroke it and things did not go as well as you planned? Perhaps you have to take your iPhone back to an Apple Store because of a hardware related issue and you are jailbroken? Well I will tell you how to restore you iPhone back to it's factory settings in a few simple steps.

Word of warning before you begin:

Restoring your device will erase all data from your iPhone or iPod Touch, including songs, videos, contacts, photos, calendar information, and any other data. All iPhone or iPod Touch settings are restored to their factory condition.

More after the jump!

Step 1.

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Step 6.

*If you are jailbroken, it is my personal opinion never to use a backup when restoring. Some may disagree, but in the end it is up to you.

Step 7.

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Step 10.

*Jailbreakers - If you want to play it safe this is where you would like to set you iPhone up as new.

Since upgrading to iPhone firmware 2.1, from time to time my camera preview -- and the pictures themselves -- have taken to breaking apart and re-arranging themselves into something pretty much unusable (though likely to fetch a pretty penny at the snootier, more vacuous galleries, no doubt).

The above picture was of a plain surface, now broken into a patchwork of planes. Happens with faces, people, and just about everything. It's not happening regularly enough, however, that I'm close to considering the nu-cu-lar option -- full on restore.

Anyone else having this problem?

As opposed to "push" style ActiveSynch, MobileMe, or Yahoo! iPhone mail, traditional POP or IMAP accounts, like Gmail or ISP mail, needs to "fetch", or check the server on a certain schedule to see if there are new messages.

Reader Mike wrote in pointing us to a thread on the Apple Discussion Forums about "fetch" email being broken with iPhone 2.1. I only fetch mail from Gmail, and Gmail IMAP is a strange and buggy implementation which gives me considerable problems beyond the iPhone, so I can't say whether anything is really broken or not in 2.1.

Reader Steffen, however, after thinking the problem could just be undocumented IMAP IDLE behavior, decided to run some tests:

Finally, I had some time to look into this thorougly. I dumped IP traffic all night to see what iPhone does. My iPhone is set to retrieve data every hour. Here's when the iPhone actually connected to my IMAP server:

09:36 PM, 10:44 PM, 11:02 PM, 12:36 AM, 06:36 AM, 09:38 AM, 09:45 AM, 09:57 AM

Looks like everything but an hour to me... Oh yeah, forgot to mention... I've turned off everything except for GSM radio do be sure to get all traffic. The last three connections occurred when I started to play around with the iPhone this morning. So, the effect that lead me to the assumption of IMAP-IDLE on the iPhone seems to be something else. It appears that the iPhone will contact IMAP more often while using it and somehow random while idling... So, no IMAP at this time, but maybe interesting as well...

Definitely interesting! Thanks Steffen!

Any other readers out there got "fetch" problems? Wacky behavior? Please let us know!

I typically choose to keep 10 episodes of any video podcast I subscribe to in iTunes. Back with version 1.0 of the Apple Remote App for the iPhone, when I would choose to play the latest episode of a show, the Apple TV would stubbornly start playing the oldest episode (sometimes oldest unwatched, sometimes just oldest) instead. "New" status seemed to have no effect.

This didn't happen if I did the same thing via the iTunes library on my computer, only when I used the Apple TV, which streams from that iTunes library. I could work around this, however, by waiting for the oldest episode to start, then tapping my iPhone screen to flip the artwork around and reveal the episode list, then tapping the newest episode again. If I jumped through that hoop, the Apple TV would begrudgingly give me the actual episode I wanted.

With Apple Remote App version 1.1? No dice. I get the oldest episode no matter what. Most perplexingly, the iPhone will initially display the proper episode name in the title bar, then visibly switch to, and begin playing, the wrong one.

(Now, as punishment for testing it and writing this, the little fella has crashed, but offered to let me restart, run diagnostics, or restore... I chose the middle option for now).

Needless to say, this has changed the App from a useful tool to non-starter, and brought the tiny little white Apple TV back out of retirement.

Anyone else experiencing this problem? Anyone have a fix?

How is your battery life doing after upgrading to firmware 2.1? Hopefully better than mine!

I thought everything was going great after I updated Friday morning. Well I had a full charge late in the afternoon and left for work. A half hour later I noticed my iPhone was a bit warm without even using it. I Looked at my battery life and I was at 50% or so! Safe to say the phone was dead not long after.

So after a full night on the charger last night I thought everything should be good today. Well I was wrong. 2 hours of standby and a 5 minute phone call later, and my iPhone looked like the above picture. Actually that is exactly how it looked! What has really got me stumped is that I checked the usage meter and it said I used 1 hour and 56 minutes! A 5 minute phone call turned into that somehow? The time since last full charge was at 2 hours, which was correct.

I did a full restore without using a back up file after this, charged my phone and while the battery did seem to last longer, the battery meter is way off still. The "force quit" did not work, nor did any soft resets.

There is a thread over at Macrumors and Apple Discussions showing others are having this exact same issue, so that leads me to believe that my iPhone is not the issue but rather a issue with the 2.1 firmware in combination with something else? MobileMe possibly?

Turning off Push... my usage meter goes back to normal. Now I'm turning push on for mail only. We'll see if it messes it up again.

If anyone has had issues like this please chime in.

UPDATE: I am happy to report that ever since I shut off push for contacts and calendars my iPhone is now working like it should. Just woke up and checked the phone, I almost have a full charge and it says I have used 1 hour and 16 minutes and time since last full charge is 10 hours. Which is correct. So it is a issue with mobileme push for sure. Whether it is getting stuck or whatever, if you are having battery issues and use mobileme or exchange try turning off push completely. Then, if it is the issue, slowly turn back on the email push feature and test it out. Then contacts and calendars...

UPDATED: Reseting everything, including the router, solved the problem.

After Apple unleashed 2.1 today, and I downloaded and installed it with nary a snag or bump, I thought everything was pretty much apps with my Apps. Needless to say, tonight I whipped out my iPhone's handy Apple Remote App to help out with a little YouTube searching, only to discover that while my libraries (desktop, laptop, Apple TV) were all still set up, none of them would connect. (They'd all worked flawlessly, immediately prior to iTunes 8 and iPhone 2.1).

I removed the libraries and tried to set them up again, but can't get the iPhone to show up in iTunes in order to type in the verification PIN. I'll continue to trouble shoot and report back if I come across any fixes.

Anyone else having this problem?

Confession: My iPhone 3G/2.x experience has been relatively painless so far. No dropped calls, almost no 3G issues, very few App crashes, no eternal syncs, etc. While Steve Jobs reportedly said I'm in the norm, along with 98% of other iPhone users, you really wouldn't know that from the intertubes. They're on fire with dissatisfied users, and reader Anon, commenting on a post, points us to a thread on Apple's discussion boards that indicates the dissatisfaction may not be ending any time soon.

The latest problem is with the 2.1 firmware -- technically the 2.1.1 firmware already shipping, apparently, on the new second generation iPod Touch -- and WiFi. Specifically, non-Apple Airport WiFi access points and the WPA security protocol (which should be what everyone is using now, right?)

While some might think this is no big deal, considering the older WEP protocol remains an option, TiPb would remind you that system can be broken in less than a minute these days, rendering it little better than no security at all.

For the record, however, I helped upgrade a 1st gen iPod Touch to 2.1 on Wednesday, and it connected to with no problems whatsoever to a Linksys WiFi router, so this might be one of the increasingly common, more complicated and multi-factor errors Apple's been encountering (like Vista BSODs with iTunes 8...)

On the iPhone side, does this mean we'll be getting 2.1.1 tomorrow as well? And will face similar problems? Or is Apple even now rushing an emergency rebuild of 2.1.1 or even 2.1.2 to finally -- finally -- give the 2%ers some stability?