The control unit: responsible for pipelined instruction decoding and initiating the relevant action
Floating Point Arithmetic Unit: for all floating point arithmetic operations
Integer Arithmetic Unit: for all integer and character operations
The Supervisor: schedules the running of jobs and switching as necessary. Atlas was probably the first machine whose control program
warranted being called an operating system.
The storage system: programs could address a million words of store which either resided in main memory or on drums.
The Supervisor made this appear like a 1-level storage system by paging blocks of information in and out of main store.
Input and output devices: the main backing store was either 1 inch Ampex pre-formatted
tape or a fixed disc. Compatible IBM 7-track magnetic tape decks were also available.
The following diagram shows the component parts of Atlas 1:-