DOS Protected Mode Services

DOS Protected Mode Services (DPMS) is a set of extended DOS memory management services to allow DPMS-enabled DOS drivers to load and execute in extended memory and protected mode. Not being a DOS extender by itself, DPMS is a minimal set of extended DOS memory management services to allow slightly modified DOS resident system extensions (RSX) such as device drivers or terminate-and-stay-resident programs (TSRs) (as so called DPMS clients) to relocate themselves into extended memory and run in 16-bit or 32-bit protected mode while leaving only a tiny stub in conventional memory as an interface to communicate with the conventional DOS environment.

Source: Wikipedia — DOS Protected Mode Services (CC BY-SA 4.0)