History of operating Systems

The earliest computers, developed in the 1940s, were programmed in machine language and they used front panel switches for input. The programmer was also the operator interacting with the computer directly from the system console (control panel).

• programmers needed to sign-up in advance to use the computer one at a time
• executing a single program (often called a job) required substantial time to setup the computer.
• First generation 1945 - 1955, vacuum tubes, plug boards
• Second generation 1955 - 1965, transistors, batch systems
• Third generation 1965 - 1980, ICs and multiprogramming
• Fourth generation 1980 - present, personal computers
• Next generation ??, personal digital assistants (PDA), information appliances

Two distinct phases in history: Expensive computers, Cheap computers