Basics of OS Flashcards
Know the basics in and out
What is an Operating System?
An Operating System is an interface between computer hardware and computer users.
Manages memory, file, process and controls peripheral devices(printer).
What are the different operating systems?
Batch, real-time, distributed, time-sharing, Multiprogrammed.
What is a socket in OS?
A software construct which allows two applications to communicate with each other.
Batch Operating System?
batching/ grouping the jobs which have the same requirements.
Time-Sharing Operating Systems?
CPU time is shared among the users.
this operating system is also known as multitasking operating system.
Distributed os?
multiple computers connected together using a shared connection .
What is a kernel
It is the core of OS. it acts as an intermediate between the software applications and the hardware
types of kernel
monolithic, micro, exo , hybrid, Nano
monolithic kernel
A monolithic kernel in an operating system is a kernel that includes all operating system code in a single executable image.
eg: linux, unix
that means kernel handles all the functions of os.
what is a process
Program under execution is known as process.
What is aging in the Operating System?
Aging is a technique which helps in avoiding starvation in the resource scheduling system. Starvation occurs when a process is unable to get the resources it needs to run, even though it is waiting for those resources. Aging works by increasing the priority of a process that has been waiting for a long time. This means that the process is more likely to be scheduled to run, even if it has a lower priority than other processes.
What are the different scheduling algorithms in OS?
First-Come, First-Served (FCFS) Scheduling, Shortest-Job-Next (SJN) Scheduling, Priority Scheduling, Shortest Remaining Time, Round Robin(RR) Scheduling, Multiple-Level Queues Scheduling.
what is a thread
it is a light weight process, it allows to divide the process into multiple threads and achieve parallelism.
what is context switching.
to switch between the tasks rapidly when one of process goes into the wait state.
multitasking os, multi-programming os, multi-processing os.
multi-tasking OS contains only one cpu and process are allowed to execute only for a particular time quantum.
multi-programming
single cpu with ready queue for process execution.
multi-processing :
has more than one cpu , context switching, time sharing, backup cpu’s.
How communication takes place between the user mode and the kernel mode.
with the help of IPC(inter process communication)
how do we switch from user mode to kernel mode and how do apps interact with the kernel.
we use system interrupt to switch from kernel mode to user mode and we use system calls to send messages to kernel to carry out a task
what are the major steps that takes place when you switch on your system.
- power supplied to all hardware.
- boot process, BIOS starts
- boot device(ssd or hdd) and the boot loader turn on the actual os.
-MBR lies on the 0th index it starts
types of storage
primary: register, cache, main memory
secondary : electronic disk, magnetic disk, optical disk and magnetic tapes
what is stored in PCB
process control block has process id , program counter, process state, priority, register, open file list and open device list.
states of a process
new, ready, run, wait, termination, suspended wait, suspended ready.
