While multithreading CPUs have been around since the 1950s, simultaneous multithreading was first researched by IBM in 1968 as part of the ACS-360 project.
虽然多线程CPU自1950年代以来一直存在，但是同时多线程在1968年才首次由IBM作为ACS-360项目的一部分进行了研究。