PC-MOS/386 is a multi-user, multitasking computer operating system produced by The Software Link (TSL), announced at COMDEX in November 1986 for February 1987 release.

MMU support for 286-class machines was provided using a proprietary hardware shim inserted between the processor and its socket.

Multi-user operation suffered from the limitations of the day including the inability of the processor to schedule and partition running processes.

The result of the case, which Arizona Retail Systems won, helped to establish US legal precedent regarding the enforceability of shrinkwrap licenses.

On 21 July 2017 PCMOS/386 was relicensed under GPL v3 and its source code uploaded to GitHub,[3] with the "year 2012" issue corrected.