This is the FM Music Composer Cartridge Software for the Yamaha CX5M Music Computer. It is boxed and complete with owners manual. Here's some info about the software...
 
Yamaha YRM‑101 Music Composer Software
The Yamaha YRM‑101 Music Composer Software is a landmark composition and sequencing program developed for the Yamaha CX5M Music Computer. Released in the early 1980s, this ROM cartridge software turned the CX5M into a powerful computer‑aided music composition system, playing a key role in the early days of digital music production.
Multi‑Part Music Composition: Enables composition of up to eight independent musical parts, each with its own voice, for full orchestration and layered arrangements. 
Notation‑Based Input: Notes, timing, dynamics (crescendo, decrescendo) and tempo changes (ritardando, a tempo) are entered using the CX5M keyboard or compatible Yamaha music keyboards, providing precise control over musical expression. 
FM Synthesis Playback: Designed to work directly with Yamaha’s FM sound architecture, allowing compositions to be played back internally or sent to external Yamaha DX‑series synthesizers and other MIDI‑compatible instruments. 
Automatic Performance & Sequencing: Acts as an early step‑time sequencer, recording and replaying musical performances with consistent timing and articulation. 
Score Output & Data Storage: Completed compositions can be printed as full musical scores using an MSX‑compatible printer and saved to cassette tape for archival or reuse. 
Iconic Vintage Software: Supplied on a ROM cartridge, the YRM‑101 is now a highly desirable item for collectors, vintage computing enthusiasts, and musicians exploring early digital composition systems. 
Whether you’re restoring a Yamaha CX5M system, composing with classic FM synthesis, or collecting historically significant music technology, the Yamaha YRM‑101 Music Composer Software represents an important milestone in computer‑based music creation.