The first transistorized computer (TRADIC), as opposed to vacuum-tube based systems, was developed in 1954, but serious commercial systems did not arrive until the 1960s, which resulted in mainframes such as the IBM System series bringing about a substantial jump in compute capability. Prior to these machines, mainframes were mainly built for government and military purposes and had certain requirements in terms of environment and security to safeguard the data. That increase in performance created a need to partition the available hardware in smaller units to enable the best possible utilization of resources. Virtualization was invented and, while very basic in its beginnings, the concept quickly evolved into a technology that enabled mainframes to multitask and run several applications simultaneously. The first commercial use of virtualization was available in 1972 with the IBM VM/370 OS.