A few operating systems, mostly UNIX clones, did exist that specifically took advantage of 286 protected mode. The 286 has user and supervisor modes, and could address up to 16 MB of physical memory. In protected mode it still used 8086 style segmented addressing, but the segments were virtual.

286 and for that matter even 386 has the segment-based memory protection mechanism that is somewhat reminiscent of Burroughs mainframes, GECOS and maybe AS/400. There are two giant issues with the idea: it does not work that well on 16b word system and it is totally incompatible with what most of existing code written in C expects. So with 386 Intel had combined that mechanism with traditional MMU and somewhat hack-ish method to turn all that of (reportedly because Microsoft wanted that for Windows/386)