2GB is currently too big for iOS 5. The capacity in About does not take account into iOS + apps; it shows the full capacity of the chip.
^^^^This is what I was trying to say. Thank you!
2GB is currently too big for iOS 5. The capacity in About does not take account into iOS + apps; it shows the full capacity of the chip.
I do think iOS 5 is bigger although I'm not sure if Siri has anything to do with it. I updated my iPad 2 to iOS 5 and it doesn't use Siri at least not yet. It's not scientific but after the update it seems like I have less free space then I did before. That said it doesn't explain why different iOS devices with 5.0 and the same capacity are different formatted capacities.
It's all part of Apple's plan. They really want to take away those 2 GB from you, for no good reason. Kidding
Basically as several people in this thread have already pointed out, 64 GiB = 59.6 GB, where GiB is base 10, and GB is base 2 (See gibibyte and gigabyte on wikipedia). iPhone 4S firmware 5.0 weighs in at 797 MB, but this is compressed. Renaming the IPSW to .zip gives you the ability to extract the compressed files. In this case there are two files that contribute to most of the IPSW file size: 038-2711-006.dmg (794.9 MB) and 018-8012-343.dmg (17.1 MB). These are also compressed and unfortunately both of these are password protected and so it's not possible to determine the size of the uncompressed files in the .dmg files (the password is probably not publicly known). But either way, the OS partition is separate from the storage partition and so this does not contribute to the storage space reported in iTunes or About screen. Apple also doesn't completely fill up the OS partition. This is made clear when you jailbreak past devices and go into Cydia, then view the storage layout.
Hope this clears up some confusion.
tl;dr The storage size is accurate.
It's tough to argue either way without knowing a) the fully uncompressed size of both OS's for each phone (password needed) and b) the way apple set their OS partition up for each device on each firmware (will be visible as soon as the 4S gets jailbroken). Actually devs might be able to see the partition setup right now; in any case I do see your point that 2GB discrepancy is significant.So if what you say is true, then the capacity of a 32GB iPhone 4 with iOS 4 on it will have more than a 32GB iPhone 4S with iOS 5. Roughly 2GB more. That is not correct.
It's tough to argue either way without knowing a) the fully uncompressed size of both OS's for each phone (password needed) and b) the way apple set their OS partition up for each device on each firmware (will be visible as soon as the 4S gets jailbroken). Actually devs might be able to see the partition setup right now; in any case I do see your point that 2GB discrepancy is significant.