the Commodore PET and Apple. Many games are unique to the TRS-80, including Duel-N-Droids, also by Christopherson, an early first-person shooter 13 Ghosts by Software Affair (the Orchestra-80, -85 and -90 people) and shooters like Cosmic Fighter and Defence Command, and strange experimental programs such as Christopherson's Dancing Demon, in which the player composes a song for a devil and choreographs his dance steps to the music. Radio Shack offered simple graphics animation programs Micro Movie and Micro Marquee, and Micro Music. Radio Shack offered a number of programming utilities, including an advanced debugger, a subroutine package, and a cross reference builder. Probably the most popular utility package was Super Utility written by Kim Watt of Breeze Computing. Other utility software such as Stewart Software's Toolkit offered the first sorted directory, decoding or reset of passwords, and the ability to eliminate parts of TRSDOS that were not needed in order to free up floppy disk space. They also produced the On-Line 80 BBS, a TRSDOS based Bulletin Board System. Misosys Inc. was a prolific producer of sophisticated TRS-80 utility and language software for all models of TRS-80 from the very beginning. Perhaps because of the lack of information on TRSDOS and its bugs, by 1982 perhaps more operating systems existed for the TRS-80 than for any other computer. TRSDOS is limited in its capabilities, since like Apple DOS 3.3 on the Apple II, it is mainly conceived of as a way of extending BASIC to support disk drives. Numerous alternative DOSes appeared, the most prominent being LDOS because Radio Shack licensed it from Logical Systems and adopted it as its official DOS for its Models I and III hard disk drive products. Other alternative TRS-80 DOSes included NewDOS from Apparat Personal Computers, and DoubleDOS, DOSPlus, MicroDOS, UltraDOS (later called Multidos). The DOS for the Model 4 line was originally called TRSDOS Version 6 but was actually produced by and licensed from Logical Systems, and is technically a descendant of the original Model I LDOS. The memory map of the Model I and III render them incompatible with the standard CP/M OS for Z80 business computers, which loads at hexadecimal address $0000 with TPA (Transient Program Area) starting at $0100; the TRS-80 ROM resides in this address space. Omikron Systems' Mappers board remaps the ROM to run unmodified CP/M programs on the Model I. A customized version of CP/M is available,