Initially, Ghost supported only FAT file system, although it could copy (but not resize) other file systems by performing a sector-by-sector transfer. Ghost added support for NTFS later in 1996, and also provided a program, Ghostwalker, to change the Security ID (SID) that made Windows NT systems distinguishable from each other. Ghostwalker is capable of modifying the name of the Windows NT computer from its own interface. Ghost added support for the ext2 file system in 1999 and for ext3 subsequently. Support for ext4 was added in September 2017.