The IBM ACS Project

The Advanced Computer Systems (ACS) project was one of two major IBM supercomputer efforts in the second half of the 1960s. ACS had significantly more ambitious performance goals than the earlier project that developed the IBM System/360 Model 91, and the ACS-1 instruction set and processor design pioneered many features that became common some two or three decades later, such as multiple condition codes and aggressive out-of-order execution. ACS also pioneered high-speed integrated circuitry that required immersive cooling in liquid fluorocarbon. Although the project was canceled, it brought many talented engineers to California and contributed to several later developments at IBM and beyond, including the Amdahl line of System/370-compatible processors in the 1970s and the IBM 801 and POWER processors in the 1980s.