Old School Machine is a term used to describe a MIMEO, which stands for Mechanical, Input, Mechanical, Output. It is a type of machine that was used in the past to produce copies of documents and other materials. It works by using a typewriter-like keyboard to input data into a mechanical device, which then produces a copy of the document. The MIMEO was popular in the early 20th century before the invention of photocopiers and other modern copying machines.