3. operating system An operating system from IBM for

their System/360 line of hardware announced in 1964. OS was

planned with several flavours that were supposed to be

compatible. OS was late, memory hungry and not able to reach

the marketing objectives of IBM for the 360/30, the planned

successor of the IBM 1401. IBM then decided to design a new

operating system for the low end machines which they called

DOS/360.