THE is an early computer Operating System, which was designed in 1968. In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... 1968 was a leap year starting on Monday (the link is to a full 1968 calendar). ...

THE was designed by Edsger Dijkstra who had some of his students help with the development, it was historically significant as it used the concept of layers as a structure. Portrait of Edsger Dijkstra (courtesy Brian Randell) Edsger Wybe Dijkstra (Rotterdam, May 11, 1930 – Nuenen, August 6, 2002) was a Dutch computer scientist. ...

Layer 0: was responsible for the multiprogramming aspects of the operating system. It decided which process was allocated to the CPU. It dealt with interrupts and performed the context switches when a process change was required. This is the lowest level.

Layer 1: was concerned with allocating memory to processes.

Layer 2: deals with inter-process communication and communication between the operating system and the console.

Layer 3: managed all I/O between the devices attached to the computer. This included buffering information from the various devices.

Layer 4: was where the user programs were stored.

Layer 5: was the overall control of the system (called the system operator)