Operating System
Provides an interface between the user and the hardware.
Purpose of the Operating System
- Application software
- Utility programs
- Memory management
- File management
- Device driver
Application Software
The role of the OS to provide a platform for these to run.
Eg. Word processors, spreadsheets, graphics programs.
Memory Management
- Allows for the transfer of data between memory.
- The allocation of memory to applications.
- Allows for multitasking as it lets more than one program be stored in memory at one time.
File Management
Allows users to:
- Create, modify and delete files/folders.
- Copy and duplicate files and folders.
- Move files and folders.
- Rename files and folders.
- Sort items into different orders, according to name, file type, date created.
- Search for particular files and folders
- Restore deleted files.
- Set access rights to files such as read only or edit.
Device Driver
Contains the instructions on how to control a peripheral device. E.g. printer
Advantages of Device Drivers
- Any device can be used with the OS, as long as there is a device driver for it.
- Drivers can be updated, to give better performance.
User management
- Allows individual users to be created
and deleted - Different access levels to be given to different users
- Keeps a log of files a user creates, accesses, edits and deletes.
Multitasking
To be able to run more than one program simultaneously.
Multitasking is only possible if…
- The OS can support multitasking.
- The computer has enough memory to hold multiple programs in RAM at once.
User Interface
Umbrella term for the way you interact with a computer as a human being.
Types of User Interface
- Graphical User Interface (GUI)
- Command Line
- Menu-driven
- Natural language
Graphical User Interface (GUI)
- Windows, Icons, Menus, Pointers (WIMP)
- Visual interface
- Interactive, optimal for mouse and touch input.
- Intuitive, easy for beginners
- E.g. laptop
Command Line Interface
- Text based
- Less resource heavy than GUI
- More commands than GUI
- Efficient
- Typically for more advanced users
- Useful for automating processes with scripts
Menu Driven Interface
- Successive menus presented to the user
- Single options chosen at each stage
- User limited to preset options
- Often with buttons on a keypad
- E.g. cashpoints, chip-and-pin devices
Natural Language Interface
- Responds to questions in spoken language
- Sometimes unreliable
- Constantly improving
- E.g. Hey Google, Siri, Alexa
Utility Software
Software used to maintain the computer system.
Types of Utility Software
- Encryption software
- Defragmentation software
- Data compression software
Encryption Software
An algorithm is used to scramble plain text into cipher text, which can only be made readable again by being decrypted with a key that only users have.
Defragmentation Software
Takes fragmented files and rearranges them to collect files and free space together. This reduces movement of the read/write head across the surface of the disk, speeding up file access.
Data Compression Software
Reduces file size so that it takes up less space and is quicker to download.
More files can be stored in memory.
