These minicomputers behave as a stand-alone computer with a number of terminals attached to it. They were small computers ( compared to the then existing mainframe computers ). This had been achieved with the introduction of transistors and core memory technologies.
The magnetic core memory or the ferrite core memory is a kind of computer memory. It stores information in magnetic ceramic rings which can store a bit(0 or 1) of information.
These rings are arranged in a grid form as shown.
But the minicomputers still had few drawbacks like large size, expensive to buy which gave way to the invention of the microcomputers which is visible in almost every household now a days.
