Unit 2 Flashcards
Whats a system software
Refers to the operating system and all utility programs that manage computer resources at a low level
it includes compilers,loaders,linkers and debuggers
What are Application Programs?
A program or group of programs designed for end users. Eg: Word processing,Graphics
What is an Operating system?
An operating system is an interface between the user and hardware of the computer system and controls the execution of all kinds of programs
it is a system software which may be viewed as an organized collection of software consisting of procedures for operating a computer and providing an environment for execution of programs.
Goals of an operating system are?
To make the computer system convenient to use
to use the computer hardware in an efficient manner
Whats the purpose of an operating system?
The purpose of an OS is to provide an environment in which the user may execute programs
Whats User Interface
a set of commands or menus through which user communicates with the programs
What are the types of Interfaces?
Command driven
What are the types of Interfaces?
Command driven
menu driven
GUI
What are the types of Interfaces?
Command driven
Menu driven
GUI
What are the ways to interact with the OS?!
OS Calls
OS System commands
What are OS calls?
Invokes services of the operating system by means of run time system calls
these are usually embedded in and activated during execution of programs
What are OS Commands
These are used to obtain services of the OS by means of commands typed at the terminal or embedded in a batch job
What are the Functions of the Operating System?
Memory Management
Process Management
Device Management
Information Management
Protection
Error Handling
Whats Memory Management?
The OS keeps track of the memory,what parts are in use and by whom?
what process management?
the OS keeps track of processors and the status if processes. It decides who will have a chance to use the processor
Whats Device management?
The OS keeps track of the devices,channels,control units and decides what is an efficient way to allocate the device.
Whats information Management?
OS keeps track of the information,its location,use,status etc and decide who gets use of the resources, enforce protection requirements.
Whats information Management?
OS keeps track of the information,its location,use,status etc and decide who gets use of the resources, enforce protection requirements.
Whats Protection?
An OS is to protect the user from unauthorized access of his files or data. And also it should protect itself from users.
Whats Error Handling?
An OS must respond to errors by taking the appropriate actions?
What are the Dual mode Operations in OS?
User mode and Kernel Mode
Whats user Mode
When the computer system is run by user application like creating a text documents or suing any application program then the system is in user mode. When the user application request for a services from the operating system or an interrupt occurs or system call, then there will be a transition from user to kernel mode to fulfill the requests
What is necessary to switch from kernel mode to user mode!?
To switch from kernel mode to user mode, the mode bit should be 1
Whats Kernel Mode?
When the system boots, hardware starts in kernel mode and when the operating system is loaded, it starts user application in user mode. TO provide protection to the hardware we have privileged instruction which execute only in kernel mode. IF the user attempts to run privileged instructions in user mode then it will treat instructions as illegal and traps to OS.
