UUP to ISO - Create Bootable ISO from Windows 10 Build Upgrade Files  

Yes this could work. NTFS has a lot of information about when files has been accessed and modified. A simple check of these values would speed up the process. Would only need to copy the needed files if dates or other flags match, without rescanning hashes.

Not sure if it works this way, but there is a slight possibility it could. So for now it's still pure speculation.

For me, updating to 15031, the high CPU usage during initialization suggests the files were hash checked on multiple threads to speed up things. I had ~60% HDD usage and about 60-80% CPU usage. Earlier HDD usage was 1-5% and CPU usage was 25-40% during this phase.

DavidY said:

Total speculation ahead!

For the files which already exist on the computer, presumably the hash values can be calculated in advance, as some sort of background maintenance task. Then the hashes can be quickly checked by the next UUP upgrade.

Presumably it doesn't know in advance which files will be kept by the next release and which ones will be updated/replaced with newer versions, so it would probably calculate the hash values of all the files in the relevant folders.

If there's a longer gap between updates, there's more time for the computer to calculate hash values, perhaps during the weekly maintenance. Then it would be ready for the next updates.

But when the new builds come thick and fast, as happened earlier this year, there may not be time for a maintenance run between builds, which means that it has to calculate the existing hashes during the update process itself - hence the high CPU which people saw during the upgrade.

Now there's been a while since the last build, I would hope that many machines will have had time to calculate all the hashes, and make the next UUP upgrade quicker. The total CPU usage is still higher , but hopefully it can be spread over longer time as a background task so not so noticeable to the user.

Is that how it works?

Actually, keeping hashes of existing files would be a not so great method - becaus if the file were to be changed, the stored hash would be incorrect. Thus, in order to keep the hash relevant to hte locally stored file, you'd need to monitor the file at all times for changes in order to produce a new hash when said change is encountered.

It would be easier to maintain it in the manner that slicendice mentions - produce a set hash value in the .cab files, then decompress and then check the hash values of the local files to the list and keep what matches and download replacements for those that do not match.

IOW, the only time the system is generating hashes is when the system is notified that a new build exists. So, during the upgrade, you will see increased CPU and disk usage, but that is the tradeoff for not having it increase during normal usage when there is no upgrade available.

Mind you, all of this was speculation as well, since I do nto know how they are doing it, and they may very well be doing it as you envisioed - and as some anti-malware programs do as well.

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PLEASE NOTICE:

The tool and the method in this tutorial both work without issues with UUP upgrade files of the latest Insider Build 15042 released earlier today.

When launching the tool you might see message The system cannot find the drive specified several times:

If this happens, don't panic. Wait patiently until the main menu is shown:

When you then start the ISO creation process the same warning might be shown at various stages. Again, just wait, ISO will be created totally normally:

Kari

Interesting - I didn't see the warnings

johngalt said:

Interesting - I didn't see the warnings

I have them appearing on one machine, regardless what I do. I have deleted UUPtoISO multiple times, re-downloaded it, yet on this one machine those error messages will always be shown.

Luckily they are harmless, ISO will be created in any case. I just thought to add the warning because I was thinking another member might see these messages, too, if I am seeing them.

I have 8 UUP machines, combination of various editions and language versions, physical and virtual machines. I get these error messages only on one VM (UK English PRO x64).

Even more interesting. Or odd, as the case may be.

Yes. Checking the code I can't find anything that should cause it.

Kari said:

Yes. Checking the code I can't find anything that should cause it.

VM hooks back to the host? Vice-versa? VMs can be a wee bit mysterious at times. Super W.A.G. !! :)

f14tomcat said:

VM hooks back to the host? Vice-versa? VMs can be a wee bit mysterious at times. Super W.A.G. !! :)

Mystery indeed. Anyway, even though I suspect this error is not very common I added a warning. Better to have it posted even if only a member or two see those messages than let a single member panic and interrupt a totally working process thinking it's not working.

Did ISO from UUPs on VM. No problems nor error messages. Went smooth as a babys bum.