EMM386

EMM386 provides you with expanded-recollection support utilizing elongated recollection. It can additionally load contrivance drivers and applications into the adapter segment, liberating conventional recollection. EMM386.EXE operates only on computers with an 80386-or-more preponderant microprocessor that have HIMEM.SYS installed.
For starters, the EMM386 has been introduced back in 1991 and has been launched in both Windows 3.0 and MS-DOS 5.0 in order to convert extended memory into the EMS (Expanded Memory Specification) type. This is the designation describing the utilization of expanded recollection. Programs utilizing EMS must first establish the presence of an installed expanded recollection manager by checking for a contrivance driver with the contrivance name EMMXXXX0.
In order for you to use EMM386, you are required to load it within the CONFIG.SYS or the FDCONFIG.SYS. The options of this particular piece of software refer to hooking the keyboard interrupt for reboot processing, reserving up to #####K for only EMS / VCPI (Virtual Control Program Interface) memory or selecting wanted pageframe for EMS. Moreover, you can also use memory that is reserved for some devices.
Furthermore, with EMM386 you can test ROM locations for UMB inclusion, access full 4G address space without RAM (MMIO - memory mapped I/O), choose not to hook keyboard interrupt for reboot processing, disallow access to address space without RAM or pick not to allow EMM386 to disable the A20 line (microprocessor connection) and enable expanded memory.
All in all, the EMM386 was and still can be very useful when dealing with various application software that require an advanced management of the extended memory within MS-DOS or Windows. With EMM386, you can make sure that your program gets exactly what it needs when it comes to expanded memory.