What is a network operating system?
- Provides services to clients via a network.
- Generally references resources elsewhere in the network.
- Optimized for performance.
What is the role of an operating system?
To be layer between hardware and users, to reduce the complexity users deal with.
To manage system resources and priorities their use between programs.
The operating system is also responsible for security such as authentication and authorization.
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Name four key resources which General Purpose computer operating systems control
- Memory (RAM)
- Processors
- I/O
- File
Name the operating system programs that manage the 4 key OS resources.
- Processor Scheduling
- Memory Allocation
- I/O Management
- File Management
What is an API?
- Application programming interface
- Allows programmers to access routines/protocols/resources in a specified manner.
What is a virtual machine?
- VM is when the OS conceals details about how the hardware is used and works from the user.
- The user is presented with a simpler interface to use.
Give two examples of user interfaces and when they are used.
- GUI - Graphical user interface. - Used for less experienced users, they have a simpler learning curve than CLI. - CLI - Command line interface. - Is used for smaller less powerful machines when running a graphical display is not appropriate, or for when automation is in mind.
What is an interactive operating system?
Direct two way communication between user and computer.
User supplies commands and data. User receives the results of processing immediately.
Example: Windows XP/7/8
What are the three classification of operating systems?
- Interactive operating systems
- Real-Time operating systems
- Network operating systems
What is a real-time operating system?
Inputs are processed in a timely manner so that the output can effect the source of the inputs. Four requirements: - Support non sequential application programs. - They have to deal with multiple events happening in parallel and at unpredictable moments. - They have to process and produce response in a specified time. - Safely critical systems must have fail safe features and guaranteed responses within a specific time.
Why would Operating Systems for Embedded systems be different than Operating Systems for GP Computers?
- Embedded systems generally fill a specific purpose, and the OSs can be specialised to fit that.
- Embedded systems can have specific size requirements, so available computing resources can be limited.
What are the layers of a computer?
User interface
Resource Management
Device Drivers
Kernel
Hardware
What two processing modes exist within OSs?
Multiprogramming - provides parallel execution of numerous applications through OS functions.
Multitasking - implies that application programmers are responsible for parallel running and interaction of applications.
What is the difference between Symmetric and Asymmetric multiprocessing?
Symmetric Multiprocessing - OS Is fully decentralized and uses the entire pool of processors, dividing them to complete system and application tasks.
Asymmetric - OS is performed entirely on a single system processor, distributing application tasks amongst other processors.
Give two benefits and a draw back of using a GUI.
+ Simple and intuitive for new users
+ Some commands may be simpler to perform in a GUI than in a CLI
- GUIs require system resources and more complex hardware than CLIs
- Some commands may be harder to perform in a GUI than in a CLI
What is swap memory?
What memory is used in Linux based operating systems run out of physical RAM to use, and the system provisions unused disk space to act as RAM to allow the operation of the OS to continue.
