86-DOS
| A sample 86-DOS session (simulated) | |
| Developer | Seattle Computer Products / Tim Paterson | 
|---|---|
| Written in | 8086 assembly language | 
| OS family | DOS | 
| Working state | Historic, unsupported | 
| Initial release | 1980 | 
| Latest release | 86-DOS 1.10 / July 1981 | 
| Marketing target | S-100-based micro-computers with 8086 processor | 
| Available in | English | 
| Package manager | N/A | 
| Platforms | x86 | 
| Kernel type | Monolithic kernel | 
| Influenced by | CP/M | 
| Default user interface | Command-line interface (COMMAND.COM) | 
| License | Proprietary | 
| Succeeded by | MS-DOS, IBM PC DOS | 
86-DOS (known internally as QDOS, for Quick and Dirty Operating System) is a discontinued operating system developed and marketed by Seattle Computer Products (SCP) for its Intel 8086-based computer kit.
86-DOS shared a few of its commands with other operating systems such as OS/8 and CP/M, which made it easy to port programs from the latter. Its application programming interface was very similar to that of CP/M. The system was licensed and then purchased by Microsoft and developed further as MS-DOS and PC DOS.