Operating Systems 1.2 History of Operating Systems G First generation 1945-1955 H vacuum tubes, plug boards(真空管,穿孔卡) Second generation 1955-1965 A transistors, batch systems(晶体管,批处理) Third generation 1965-1980 H ICs and multiprogramming(集成电路,多道) G Fourth generation 1980-present personal computers(个人电脑) Gao Haichang, Software School, Xidian UniversityOperating Systems Gao Haichang , Software School, Xidian University 11 1.2 History of Operating Systems First generation 1945 - 1955  vacuum tubes, plug boards(真空管，穿孔卡) Second generation 1955 - 1965  transistors, batch systems（晶体管，批处理） Third generation 1965 – 1980  ICs and multiprogramming（集成电路，多道） Fourth generation 1980 – present  personal computers（个人电脑）