The last line shows the number of unallocated blocks on the disk (again as a pseudo "line number"), followed by the words "BLOCKS FREE." On the Commodore 64, entering will flood the screen with garbage instead of loading the directory into BASIC RAM. This is because the drive assigns the directory a load address of $0401 (1025), which is equivalent to the start of BASIC for the Commodore PET, but corresponds to the default screen memory in the C64 (starting with the second character on the first line of the screen). Viewing the directory with a command overwrites the BASIC program in memory. The DOS Wedge and various third-party cartridges and extenders such as Epyx Fast Load, Action Replay, and The Final Cartridge III allow viewing of the disk directory using special commands that load the directory into screen memory without destroying the current BASIC program. Some versions of Commodore BASIC include a DIRECTORY or CATALOG command that performs the same function. The following file types are supported: SEQ A sequential file is a data file that can be linearly read from start to finish. SEQ files are commonly used to store documents or text files created by a word processor or other such editor. A sequential file is analogous to a flat file in Linux or UNIX, in that it has no specialized internal structure. It is not possible to position to any arbitrary location in a sequential file, as there is no analog of the lseek kernel call found in UNIX-like operating systems. PRG PRG files normally contain executable program code, although they can also be used for data files. The first two bytes of the PRG are read by the kernal "load file" routine and used to determine the load address (they are stored in a little endian format). REL A relative file is a variation of the sequential file type, in which an indexing mechanism referred to as side-sectors is present to permit record-oriented access. Records may be a maximum of 254 bytes in size and are addressed by a one-based cardinal number, permitting true random access to any part of the file. USR A user-specified file has an internal structure that is identical to that of a sequential file. Commodore's original purpose for this file type was the facilitation of DOS development, as the file content could be copied into a drive buffer for execution