Operating systems Flashcards
What does an operating system allow people to do?
Allows users/applications to communicate with the hardware (Intermediary between users/application and hardware)
provides users an environment in which a user can execute programs conveniently and efficiently
What is a batch OS?
Users submit their jobs/programs/applications to the computer’s queue, the computer read the queue, do computation and output the result to the user.
What are the disadvantages of a batch OS?
Lack of interaction between the user and the job, Users cannot set the jobs priority in the queue and CPU is often idle waiting for the I/O (input/output) operations.
What is a timesharing OS?
CPU time is shared among multiple users and multiple jobs/programs/applications, i.e. instead of doing one job at a time, the CPU switch between jobs when the CPU is idle (waiting for some I/O operation).
What are the advantages of timesharing OS?
Provide quick response, avoid duplication of software and reduces CPU idle time.
What is a distributed OS?
Use multiple CPUs to serve multiple applications and multiple users. The CPUs may be located at different sites.
What are the advantages of a distributed OS?
Resources may be shared with other users located at different site. If one site fails, the remaining sites can continue operating and finishes the computation. Better service to the customer. Reduction of the load on the host computer. Reduction of delays in data processing.
What is a Network OS?
OS runs on a server and provides server the capability to manage data, users/groups, applications, security and other networking functions.
What are the advantages of a NEtwork OS?
Resources may be shared with other users located at different site. If one site fails, the remaining sites can continue operating and finishes the computation. Security is server managed. Centralized servers are highly stable. Upgrades to new technologies and hardware can be easily integrated into the system. Remote access to servers is possible from different locations and different types of system.
What are the disadvantages of a Network OS?
Dependency on a central location for most operations. Dependent on the server regular maintenance and updates. Lack of privacy control.
What is a Realtime OS?
A data processing system in which the time interval required to process and respond to inputs is so small. Its function is well defined (limited) and has fixed time constraints. It is used in air traffic control system, weapon system, medical imaging systems, etc.
What is a GUI?
Graphical User Interface (graphical representation of a shell)
What is a CLI?
Command Line Interface (textual representation of a shell)
What is the kernel?
Lowest level software in the OS. It is the core of the OS that actually communicates the command that you wrote on the shell to the relevant hardware, relays the hardware’s output to shell and manages the hardware/resources.
What is the shell command interpreter?
Program that process the command (system call) that you enter and pass it on to the kernel. The shell will then display the output received from the kernel. It is located between the application/user and kernel.
