OS1: Operating System Fundamentals – Unit 2 History and Evolution of Operating System

Introduction Operating system was absent in the first commercial form of electronic computer launched in 1940's. Rows of mechanical switches were used to enter programs. At that time, programming languages were not in use. Naturally, there was hardly any idea about operating system. The user had sole use of the machine and would arrive armed with program and data, often on punched paper tape. The program would be loaded into the machine, and the machine would be set to work until the program completed or crashed. Programs could generally be debugged via a front panel using switches and lights. It is said that Alan Turing was a master of this on the early Manchester Mark I machine, and he was already deriving the primitive conception of an operating system from the principles of the Universal Turing Machine. Later machines came with libraries of support code, which would be linked to the users’ program to assist in operations such as input and output. This was the genesis of the modern-day operating system. However, machines still ran a single job at a time; at Cambridge University in England the job queue was at one time a washing line from which tapes were hung with different coloured clothes-pegs to indicate job-priority. As machines became more powerful, the time needed for a run of a program diminished and the time to hand off the equipment became very large by comparison. Accounting for and paying for machine usage moved on from checking the wall clock to automatic logging by the computer 2.0 Objectives By the end of this unit, you should be able to: • Discuss the history and evolution of operating system • State the basic functions of the operating system • Differentiate the various features of each generation of the operating system