EMS Memory was designed to overcome the memory limitations of the original IBM XT. The original architecture of the IBM XT has 20 address lines which gives a maximum memory space of 1MB. The top 384k is typically reserved for BIOS, leaving the lower 640k available for applications. In 1981, this seemed to be an obscene amount of memory. As time went on, this was not enough, but what to do when you have a hard limit on the amount of RAM you can address? The answer was EMS memory, co-developed by Intel, Microsoft & Lotus. While this was a nice solution, you must have an application which is aware of how to use type of RAM. Lotus 1-2-3 was one of the first, but later Windows, and many games and apps would make use of EMS to speed up gameplay and load more information into memory at once.
Purchase is for PCB only. Parts will need to be purchased separately, and assembled. The link below contains a full bill of materials to complete the build, as well as the instructions on how to set the board jumpers.