Serial Processing (串行处理或称人工操作) ° No operating system a single program called a job These machines were run from a console consisting of display lights toggle switches, input device and printer These early systems presented two main problems:Serial Processing （串行处理或称人工操作） • No operating system。 • A single program called a job。 • These Machines were run from a console， consisting of display lights 、toggle switches、 input device and printer。 • These early systems presented two main problems：