sparseify

ext2/ext3

• http://intgat.tigress.co.uk/rmy/uml/sparsify.html

fat12/fat16/fat32

• Nothing yet.

ntfs

• $Bitmap contains a bitmap covering the entire block device, including metadata and special files.
• $MFT contains block size, for computing bitmap offsets. This is usually 4096, for compatibility with stream compression, but it can be different.
• ntfsprogs (http://www.linux-ntfs.org) comes in handy: ntfsinfo --mft <dev> for block size, ntfscat <dev> \$Bitmap for bitmap
• This has to be the easiest of all, ironically.

ffs/ufs/ufs2

• Nothing yet.