What roles and functionality does an operating system provide?
Hide hardware complexity from applications and developers
Manages the underlying software
Provides isolation and protection
Guarantees applications can never access each others memory
Threads can only exist on the kernel level
Which of the following are components of an operating system?
Microsoft Word
Device Driver
Web Browser
Kernel
File System
An operating system abstracts and arbitrates the use of the computer system.
Distributing memory between multiple processors is an example of abstraction.
Supporting different types of speakers is an example of abstraction.
What is an embedded operating system?
A type of operating system that targets servers.
A type of operating system that targets desktops.
A type of operating system designed to be compact, efficient at resource usage, and reliable (such as for a smart phone/tablet).
A type of operating system that targets mainframes.
Check all UNIX based operating systems below.
Windows
Mac OS X (BSD)
Linux
Android
Which of the following is an abstraction?
Socket
Create
Schedule
Write
Which of the following is a mechanism?
Process
File
Thread
To achieve it's goals an operating system supports a number of higher level abstractions and then a key number of mechanisms that operate on top of these abstractions.
Operating systems do not implement policies to determine how mechanisms will be used to manage the underlying hardware.
The policy Least Recently Used (LRU) decides that the pages that have been least recently used over a period of time are the ones that are no longer used in physical memory but instead to be used on disk. This is also known as
Swapping
Switching
Transferring
Upkeep
What are some good guiding policies when designing an OS? Check all that apply
Separation of mechanisms and policy
Tight coupling of mechanisms and policy
Optimize for edge cases
Optimize for the common case
To achieve it's role of controlling and managing hardware resources on behalf of applications, the application must have special privileges. This is achieved by distinguishing between at least two modes of
Kernal and User
Kernal and Admin
Admin and Master
Privileged and Kernel
The operating system must operate in privileged kernel mode.
User - Kernel switch is supported by which hardware?
The CPU
Motherboard
RAM
GPU
What is a trap instruction?
When an application attempts to perform privileged operations in user mode
An instruction that leads to buffer overflow
Any instruction sent to the CPU when close to using max RAM
Any instruction performed by incompatible hardware.
What happens when a trap instruction occurs?
Control is switched to the OS at a specific location
The OS checks to see what caused the trap to occur
Grant access or perform terminate the process if the instruction was illegal.
A system call
A system call is when the operating system gives privileged access to an application. Examples of this are open(file), send(socket), and malloc(memory).
