FlexHex
FlexHex is a freeware hex editor for Microsoft Windows that can edit files, NTFS alternate streams and sparse data, OLE compound files, logical disks, and physical drives. Technology. FlexHex uses the 'edit stack' model, representing the file being edited as the unchanged original stream and a stack of primitive editing operations. The original file is kept intact and gets modified only when the user selects the Save command. The advantages of this model are 1) the file does not need to be read into memory so there is no file size limit, and 2) an unlimited Undo/Redo list  can be implemented simply by traversing the operation stack. FlexHex is written on Visual C++ and MFC, which makes it very fast while keeping the size small enough. Features. In addition to the standard features more or less typical for other hex editors, FlexHex offers a few unique ones. Specifically, FlexHex is the only hex editor that can create or edit NTFS alternate streams, sparse files, and OLE structured storage.