Page 1 of 1

Aclaration about DoubleSpace2 wim file

PostPosted: Fri Apr 24, 2015 3:19 am
by eried

I am testing DoubleSpace2 in a small tablet with very little free space. I noticed how it removed a partition and created the undo disk but, it is necessary to leave the wim file inside the same partition?

1) Can I move it somewhere to free more space? I mean: use an sd for the undo disk and the other wim file?

2) Why does I need the undo disk / recompress option?

Also I think there is a bug, if I launch the app via the pinned button in the taskbar it launches maximized. I tried to extract these answers from the feature list but they aren't explicitly explained.

Re: Aclaration about DoubleSpace2 wim file

PostPosted: Fri Apr 24, 2015 10:09 am
by admin
1) Your entire disk image (except files that have been deleted and updated) is actually contained inside the c:\zipmagic.wim file. So no, it is not advisable to move this to another disk. For example, if you used an SD disk for this purpose, disk reads would get exceptionally slow; whereas at present I don't think you notice any difference from the compression.

Note that you are also free to delete the WIM file on the Undo Disk. When you use an Undo Disk, it protects you from accidental power loss or other unexpected failures; it also serves as a backup if you ever want to refresh your system using that saved WIM image. This WIM is identical to the WIM file you have on your disk (even as you change the contents of your disk later on, the WIM does not get updated automatically); so this means that you can delete it safely once processing is complete. Should you ever need to reclaim it, you can just copy it over from your C: drive - as long as there's no mechanical defects with drive C:, this will always work (even while Windows is running).

2) I suppose I have already answered this question above. You don't actually need an Undo Disk the first time you use DoubleSpace, because as DoubleSpace works the drive, it will automatically delete each file it adds to the WIM; and since the WIM is compressed, you'll never run out of space with this approach. However, because files are being deleted from disk before the entire WIM has already been built successfully, if you accidentally lose power during the operation, this means your system may be inoperative. This is why using an Undo Disk is recommended: Since the WIM is created on an external disk, even if you lose power before its ready, there's no consequence to your main system. Even if you lose power after its ready, you can always restart the process with the WIM on your Undo Disk, so there is virtually no risk to your data when you use the Undo Disk option.

Of course, when you are recompressing a disk which was compressed before, an Undo Disk now becomes mandatory: This is because sufficient space cannot be guaranteed for compression to work on-the-fly as in the first-time compression scenario. You could potentially end up with two very large WIM's on disk, containing virtually identical data - and your disk would almost certainly not have enough room to accommodate two images of itself.

Now, why do you need a recompress option? There's many reasons I could think of:

a) To change your compression strength
b) To recompress new files you have added to disk (not automatic with WIMBoot technology)
c) To compress files you have updated on disk (not automatic with WIMBoot technology)
d) To recover space from files inside the WIM that you have since deleted from disk (not automatic with WIMBoot technology)

While DoubleSpace also invokes DriveSpace to use NTFS compression (which automatically recovers space from deleted files, and dynamically recompresses any new/updated files) on your Excluded Folders, as far as the files inside the master WIM image are concerned, they are set in stone. This results in a WIMBoot "Space Bleed" problem as has been described here: ... ion.65995/. This space bleed can get as severe as WIMBoot compression falling substantially behind NTFS compression - despite being actually far superior in data compression technology itself!

DoubleSpace solves this problem by offering drive recompression, and also offering customizable folder exclusions for folders which are frequently updated on your PC. Using NTFS compression results in the best possible space savings on frequently updated folders (its best to never include such folders inside a WIM file at all).

In this way, DoubleSpace and DriveSpace work together to maximize your available free disk space; combining the best technologies Microsoft has to offer, in a user-friendly and one-click package.

PS: The maximize issue seems to occur only on some very limited range of tablets, it is cosmetic only and has no harmful side effects.

Re: Aclaration about DoubleSpace2 wim file

PostPosted: Fri Apr 24, 2015 11:49 am
by eried
Wow, thanks for the very informative answer. All clear now. Good to see these minor issues were fixed in Win10 I hope all the drivers from my cheapo tablet work properly in Win10 :D when it comes to public

Re: Aclaration about DoubleSpace2 wim file

PostPosted: Fri Apr 24, 2015 1:50 pm
by admin
Actually, if you still want the best available compression, you'll still want to use DoubleSpace on even Windows 10. It compresses 10%15% better on average. But if you're not that desperate for space, DriveSpace would be more convenient, since you don't even need to restart Windows to use it.

Re: Aclaration about DoubleSpace2 wim file

PostPosted: Fri Apr 24, 2015 2:50 pm
by eried
I am just looking to get an usable toy tablet (couldn't resist the price! 113 USD!) >:) and it actually looks pretty nice with DoubleSpace2, with the free Office there is about 6 gigs free, much better than before: ... 8081i.html

Re: Aclaration about DoubleSpace2 wim file

PostPosted: Sat Apr 25, 2015 11:37 am
by admin
That's wonderful!

Thank you so much for helping spread the word, you have made my day :)