Hard Disk Unit
| Brand | PPG |
| Manufacturer | Palm Products GmbH |
| Designer | Wolfgang Palm |
| Function | Digital Recorder (12 minutes of sampling with 16-bit resolution and a 44.1kHz sampling rate) |
| Produced | 1986-1987 |
| Country | Germany |
| Model ID | HDU |
| Form Factor | 19" Rackmount |
| Signal Path | Digital Hardware |
| Channels | 4 Track (10 Tracks total, 4 simultaneous) |