Extended Memory Specification

LIMA XMS offers 18 functions for an extended memory programming interface that can access memory above 1MB. It is addressable by systems with an Intel (or compatible) 80386SX (or higher) microprocessor architecture. LIM XMS addresses three regions of memory:

A user can start a specific DOS version within a DOS session with OS/2 2.0. When a DOS session starts with a specific DOS version, extended memory blocks serve only for data storage; they cannot be accessed by an application. When a DOS session starts, memory in an extended memory block region can be moved to conventional memory, and a conventional memory region can be moved to the extended memory block region. In practice, the maximum extended memory block region is 16MB, divided into as many as 255 blocks.

If an application in a DOS session encounters an error as a result of insufficient extended memory: