Virtual Storage Extended
(VSE, formerly DOS/VSE) is a multitasking, IBM 370-architected operating system similar to Multiple Virtual Storage (MVS).
VSE run jobs in partitions rather than address spaces, and uses POWER for input/output rather than JES, but is largely similar to MVS. Subsequent VSE/ESA releases gave VSE the XA-370 channel architecture, 31-bit virtual and real storage support, and data spaces. VSE is the IBM operating system on one-third of installed IBM 4381s and a significant proportion of IBM 9370s as well. It offers transaction processing and batch processing capabilities well beyond Virtual Machine's current capabilities, and has a close affinity with MVS.