Early Operating Systems

Study Notes

Early computers had no operating system and required control software to be loaded each time they were started using paper tape or punched cards.
In the 1970s, home computers like the Acorn BBC B used an internal ROM chip to store part of the operating system and a cassette tape machine to load the remainder.

With the development of hard disk drives (HDD), operating systems were stored on the hard disk, and start-up of the motherboard was handled by the basic input/output system (BIOS).
The BIOS contents are stored on a flash memory chip, and its configuration is stored in CMOS memory, allowing it to be altered or deleted as required.

An operating system provides an environment for applications to run and a usable interface between humans and computers.
It disguises the complexity of computer hardware and provides a human-computer interface (HCI) through a graphical user interface (GUI) or command line interface (CLI).

A GUI allows users to interact with computers using pictures or symbols (icons) and provides various technologies and devices for the user interface.
One of the first commonly used GUI environments was WIMP (windows, icons, menu, and pointing device), which was developed for personal computers.
Modern computer systems allow multiple windows to be open at the same time, and a window manager looks after the interaction between windows, applications, and the windowing system.

Smartphones, tablets, and many computers now use post-WIMP interaction, where fingers are in contact with the screen, allowing actions such as pinching and rotating.
Touch screen technology has made flexible HCIs readily available, allowing users to launch applications by simply tapping icons on the screen.