Operating Systems Lesson Objective: Understanding the functions of an operating system. Learning Outcome: Answer some basic questions on operating systems.

A computer … CPU (Central Processing Unit) Memory (e.g RAM) Backing Store (e.g Hard Disk) Input Devices (Keyboard, scanner) Output Devices (Monitor, Printer) The computer hardware

The OS is the software that takes control of the physical devices CPU (Central Processing Unit) Memory (e.g RAM) Backing Story (e.g Hard Disk) Input Devices (Keyboard, scanner) Output Devices (Monitor, Printer)

Memory Management Software wants to get control of as much RAM as possible because more RAM usually means they run faster. How do we stop the first item of software grabbing all of the RAM and stopping others from getting it?

Multi-tasking Software wants to get as much CPU time as possible. Sharing out CPU time between different software is called Multi-tasking.

Peripheral management Controlling which software gets control of equipment attached to the computer (peripherals)

It’s good to share Memory Management CPU time (Multi-tasking) Peripheral Management These are some of the tasks of an Operating System

Also … User Interface How does it look? Here to put the icons? Which language to display? Security Log-in, protect files from other users, Firewall, Anti-virus …etc.

What does an Operating System do? An operating system is Software The allocation of RAM to appsMemory Management User Interface Multi-tasking Peripheral Management WIMP or other- how does it look? Security Allocates CPU time to each process Printers, router, etc. Logging in, firewall, AV