Description
MVS/XA, or Multiple Virtual Storage/Extended Architecture, was a version of MVS that supported the 370-XA architecture, which expanded addresses from 24 bits to 31 bits, providing a 2 gigabyte addressable memory area. It also supported a 24-bit legacy addressing mode for older 24-bit applications (i.e. those that stored a 24-bit address in the lower 24 bits of a 32-bit word and utilized the upper 8 bits of that word for other purposes).
