So does this mean the file is downloaded in two pieces??
Guess so. First file might be a manifest/installer of sorts. It comes down about twice as fast as the second part. Or, it could be that I've been using the full files for so long, that doing it from the device it needs to re-acclimate itself. Apple's weird like that.
Ok, so this only happens the first time you update on the device, so it must be some kind of manifest or app store certificate. The second time you update it only does the update circle once.
Still, the past two days of updates have been 2GB ventures each day as everyone starts updating for iOS 11 (and subsequent bug fixes).
Plus (naturally), Apple released Xcode 9.0 yesterday (~6GB), which contains updated emulators and build code for every Apple device on the market, including iOS 11 and High Sierra.
So against better judgement I decided to update macOS to 10.13 High Sierra.
The 5.17GB download went fine and made sure I had a backup of everything.
Then I grit my teeth, winced, and initiated the process at 7.50 this morning...
It just got done... 8 HOURS LATER.
In it's defense, I think it goes through everything and tries to compress and catalog everything in a new file system, which is fine (and a bit of magic, if not dangerous to do on a single SDD if you think about it)... unless you have a 256GB iTunes folder of music and movies, and another 120GB in two Parallels VMs.
Not saying everyone has a hard disk full-o-stuff like I do, but if you do, be prepared for a long ride.
Now to see how many kernel mods and rebuilt Linux things got broken.
I'm running an iMac 9,1 so 10.11.6 is as far as I can go on this old of hardware.
I went to an auction this spring at a local university looking for a newer Mac but there was nothing newer enough to warrant changing.
I'm too tight (and poor) to shell out for a new iMac so I'm here for a while but elCapitan has treated me pretty good.
I do have a "Hackintosh" I keep as a backup spare but have only upgraded it to Yose. I like the DU better and plan to leave it there.
I have found that late night OS updates are the quick and easy route. (about 1.5 to 2 hrs) daytime 8 hrs= :/
As for IOS updates (iPhone 6) I havent had any double downloads, I think your 2d assessment is correct.
Mine's a 10,1 so I'm figuring High Sierra might be it's last rodeo.
Turns out the 8 hours was in fact converting the SDD to the new Apple File System - only 177GB free on a 750GB drive...
And it's going to have to last for a good while. Wife needed a new car and I'm in a wait state for about another year until the pension and IRA kick in.
I had not been paying attemtion to changes of the file system but had seen somewhere that Apple was considering going to zfs.
My Solaris UNIX server uses zfs and the pool doubles the drive space for the same amount of data but this is in case a HDD crashes there is a mirror copy on another drive. (similar to raid)
zfs on a single drive would divide it into 2 equal partitions and mirror one on the other. While this works it does not protect against drive failure since it's all on the same physical device.
As I said, I haven't looked into what they're doing as far as a new file system and it could be something totally different. Almost no Apple computer has multiple hard drives so zfs doesn't make sense. COW (cache on write) might advantageous enough. idk
It is something I need to check out.
177GB free still isn't too bad. I've got 386 free out of 500.
I've been looking into APFS vs HFS+.
Unless your HDD was already pretty full I don't understand why it would fill up much more.
I would recommend that for future "major upgrades" you wait until there's a dot release and beware of the "bleeding edge".
I've been there plenty and learned to stay back a comfortable distance.
Anyway IMO APFS is another step to turn all of our computers into big smartphones.