Clonezilla is a partition and disk imaging/cloning program similar to True Image®. It saves and restores only used blocks in hard drive. Two types of Clonezilla are available, Clonezilla live and Clonezilla SE (Server Edition).
This program runs on Debian-based Linux systems and performs raw cloning from disk to disk, disk to image, and image to disk. It is powered by the dd tool.
Much better here: https://sourceforge.net/p/sysbackres/
https://github.com/shampuan/Zeus-Raw-Copy
This is both a server and client to image over netcat, written in Perl. This was done for a course project.
Note that this is not fully functional there are some errors that need to be fixed. I'm no Perl wizard either, so it may be kind of messy.