Operating Systems & System Software

Learning Objectives 4.4.1 Understand what an operating system is and the functions of an operating system [file management, input/output, resource allocation, process management, network management, user management] FUNRIP 4.4.2 Understand that application software such as a web browser, word processor, spreadsheet or apps are computer programs hardware operating system application software user

Starter In pairs, list all of the different operating systems you can think of. Which operating system would this computer run?

Why do we have operating systems? Before the stored-programme concept programmers had to interact with the hardware directly, This meant setting switches and plugging things in. Then along came the ability to store a program 

Application Software Application software such as a web browser, word processor, spreadsheet or apps are just computer programs. On a Windows OS these will have a file type of .exe The operating system: gives each process a unique process ID allocates space in memory to hold the instructions and data for a program assigns priority which determines the order in which processes will run links processes with a user.

Operating Systems Role File management- F User management- U Network management- N Resource allocation- R Input/output- I Process management- P

File Management The operating system manages the storage of files and directories (folders). The operating system stores files in a hierarchy of directories.

User Management The operating system also manages the user(s) of the computer system, providing users with an interface to the computer system, privileges to perform certain tasks and security features to protect the users and the system. GUI’s (Graphical User Interface) CLI (Command Line Interpreter)

Network Management It is the operating system that manages the operation of the computer system’s network connections. Identifying what devices are present on a network, analysing the traffic sent through it. It also tries to spot and fix errors in the network.

Resource Allocation A resource is any part of the computer system. Examples include a printer, memory, hard disk drive or processor time. The operating system allocates the computer system’s available hardware to the programs running (processes) at any one time. While a program is running, the data and instructions are stored in the main memory and it is the operating system that allocates appropriate memory to each program. The operating system also ensures that instructions and data do not interfere with each other

Input / Output The operating system manages data transfers between the CPU and the input and output devices, such as the keyboard and printers (peripherals). The software that allows this data transfer may already be part of the operating system, or the user might need to install a driver to handle input and output from a particular device.

Process Management The heart of managing the processor comes down to two related issues: Ensuring that each process and application receives enough of the processor's time to function properly Using as many processor cycles as possible to work efficiently

Activity Process Scheduling task Runnable Running Waiting

Activity Using the knowledge just learnt you need produce a multiple choice game in Python.

Homework Take a screen shot of the processes running on a computer and annotate it to show the name of the process (identifying whether or not it is application software, the process id, the priority (if shown) and the user. Now find out how to list the processes running on your mobile phone. Due in 2 lessons time

Plenary What does FUNRIP stand for? What is application software, how does the OS in windows disguise between application software and other processes? Can CPU’s multitask? Explain why? How does the CPU processes information?