Can I use CompactOS technology in Windows 7 or 8.1?

Question

Can CompactOS in Windows 10 be used to compress win 7 or win 8.1 available on the same disk (dual boot mode)?

Similarly can I use this to compress other drives also?

Answer 1

No, the compactOS feature is Windows 10 only and not available to older versions. Try to cleanup WinSxS to reduce the size of Windows 7/8.

Answer 2

No. The CompactOS feature uses the new 4K XPRESS Huffman compression algorithm instead of the default LZNT1 algorithm in NTFS. That's one of the new algorithms introduced in Windows 10 so you can't use it in prior Windows versions. That's also why it's possible to tweak NTFS compression ratio in Windows 10

Anyway Windows 8.1 already supports WIMBoot for reducing system footprint, although it's not as efficient as CompactOS

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• WIMBoot Explained: How Windows Can Now Fit on a Tiny 16 GB Drive

There's nothing similar in Windows 7

Similarly can I use this to compress other drives also?

No, compactOS is for compressing selected system files that are read-only. It won't touch any user files or files that are written to a lot

However NTFS already supports compression since its start, so just use that feature. It's what files with blue names or blue arrows are about. To compress a file or folder right click on it > Properties > Advanced and check Compress contents to save disk space

You can compress the whole drive by checking the compress option while formatting it, or in the properties window

It's also possible to compress from command line with the compact command. Run compact /s /c /f path\to\file\or\folder or whatever appropriate options