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I used COMPACT but it didn't compress the file except changing the file color from black to blue. I only used

COMPACT c:\fileToZip.bak /C

Did i make wrong?

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up vote 4 down vote accepted

Blue colour files indicate that the file has been compressed. Right click on the file, select properties and you'll see that the size consumed on disk has been reduced to the compressed size.

Example: Took a file of 9kb, compressed it. Now Windows Explorer still shows that the file is 9Kb but the properties show that size consumed on disk has gone down to the compressed size, indicating compression was successful.

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And the compressed file size is the size of a cluster (minimum file size on disk)... so the compression probably did a bit more work than that. – David Sherret Apr 4 '13 at 19:01

On Windows XP (2000?) NT 4.0 or newer with an NTFS partition, compact uses filesystem compression to compress the file, and the file appears unchanged in Windows Explorer. If you're looking to zip the file, you should download the CLI of IZarc (or similar) and put it somewhere in your PATH.

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Actually, NT 4.0. (I don't remember if NT 3.5 supported NTFS compression) – grawity May 25 '10 at 13:29

NTFS compression is loss-less bit compression. Video and picture files are very compressed already. The only way to make them smaller is to use a smarter compression scheme, perhaps fractal / wavelets, or to reduce the quality or size(in pixels) of the images using the original compression scheme.

Compact works well with text or data files, others not so much.

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