QEMM

QEMM, the Quarterdeck Expanded Memory Manager by Quarterdeck, was a popular memory manager for the DOS operating system. QEMM provides access to the Upper Memory Area (UMA), Expanded Memory Specification (EMS) memory and Extended Memory Specification (XMS) memory. Many DOS programs required a high amount of conventional memory, and QEMM helped to increase the amount of free conventional memory by loading programs to the UMA. Many programs, such as Lotus 1-2-3, early version of Microsoft Windows, and many games, also used the EMS and XMS memory.

Originally, it was called QEMM386, and had a complementary product called QRAM that worked in a similar manner on 286's that had some specific Chips and Technologies chipsets. The 386 was dropped when the Intel Pentium was released. QEMM386 and DESQview that were shipped as a bundle were called DESQview386.

The principle competitors of QEMM were BlueMax/386Max, and HeadRoom/NetRoom.

Beginning with version 5.0, MS-DOS started to include a memory manger of its own called EMM386. In some situations, EMM386 was good enough, but QEMM still usually freed up more conventional memory than EMM386 did.

While popular when DOS programs were the mainstream, QEMM eventually became irrelevant as Windows programs replaced DOS programs. Versions of QEMM were released into the era of Windows 98, also being compatible with it.