How to read unallocated space?

With each logical reading function, eg NTFS, CD-ROM there is an option to read the unallocated space. The sequence is that the disk is read logically, and hence all used sectors are known. After this, all previously unread sectors are read, and each sector, or cluster is tested to see if it is a possible start of a file. This based on the first few characters of a file, and then sometimes some rather more extensive tests looking for a certain type of data. For NTFS disks, any file compression will be detected and automatically expanded. It does not matter if just one file is compressed, or all files compressed, they will be detected. It will even detect NTFS compressed files left behind on a FAT, MAC, or HPOFS disk .(This is more than many data recovery programs will achive).

One issue with raw recovery is that the start of the file can be easy to detect, but often the length is not clear. CnW Recovery software will often continue adding to a file until a new unique start is found. In these cases a file can be shown as many MBs, although the actual data is only 100K. Fortunately, in many cases, an application will read this file, and ignore erroneous data at the end. As the CnW Recovery software develops, where possible, files will be stored at the correct length. With continuous files, extraction rates can be extremely high, with fragmented files, there can be major problems.