It is estimated that many users were shocked when they received the iOS8 push yesterday, and they needed 4.7G of free space to upgrade. But is that really the case?
In fact, it is very easy to understand that if you do not connect the computer and directly use the OTA (On The Air) method to upgrade, it is quite normal to occupy 5GB of space. This space will not be permanently occupied, and most of it will be released to users after the upgrade.
5GB space is only temporarily occupied
Everything should start from the principle of OTA upgrade. The mobile phone manufacturer pushes the software upgrade information to the user, and then our mobile phone will receive the system update prompt. After clicking Upgrade, your phone will do the following:
Download the new firmware to the internal memory of the phone;
Restart the phone, decompress the firmware in the phone storage, and the decompressed file is also stored in the phone internal storage;
Run the unzipped installation package to replace and upgrade the existing system files;
After installation, delete the firmware and unzipped installation package.
Take the iPhone upgrading iOS8 for example. The firmware size is 957MB (this firmware can be understood as the RAR compressed package on the computer). After decompression, it can reach 2GB. In order to ensure the installation, the files before and after decompression should be placed in the phone space, so that there will be a total of 3GB. During the installation process, the system also needs some space to store temporary files and user personal data. In total, it is easy to understand that 5GB is reserved.
After the installation is completed, the firmware package, installation package and temporary files will be deleted, and the 5GB will be released naturally. The author compares the available capacity of the iPhone 5s when running iOS 7 and iOS 8. The former is 12.9GB, and the latter is 12.2GB. The difference of 700MB is the real price you will pay after upgrading iOS 8 - they will never come back.
So you should ask, why does OTA have to download a compressed package instead of a complete installation package? The reason is simple, because smaller compressed packages download faster! For many friends who have poor Wi Fi network or pay by traffic, it is particularly important to compress the installation package. After all, the volume before and after compression can be as much as twice as different.
No matter how secure it is, we cannot guarantee that there will be no accidents during the OTA upgrade. To prevent this from happening, after decompression, the original compressed package is still kept in the phone's storage space, so that it can be used again after the upgrade fails. As a result, many 8GB and 16GB users will complain when the compressed package and installation package are put together.
What should 8GB and 16GB users do?
Those who complain are the ones who complain, but those who use 8GB or 16GB devices don't need to worry at all. If you can't spare 5GB space after racking your brains, you can upgrade through iTunes. First connect the iPhone/iPad/Touch 5 to the computer, then select "Check for updates" in "Summary" - "Version", and the system will automatically download and install the new firmware. It is recommended to back up the existing data in the device before upgrading.
Another method is to download the firmware package directly, then press Shift in iTunes and click "Restore", and select the downloaded firmware package to upgrade. The above two methods have no requirements for the remaining space in the mobile phone, which is definitely the gospel of the 8GB and 16GB parties.
Finally, the price of upgrading iOS 8 is 700MB.
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