In C/C++, the fork() function is used to generate a new process known as the child process. We can do searching within a fork() process. Problem statement – Write a program to search the key element in parent process and print the key to be searched in child process. Examples: Input : Key=7; array[5] = { 2, 5,… Read More »
A page table is a data structure used by virtual memory system in a computer operating system to store the mapping between the virtual addresses and physical addresses. Multilevel page tables are split into two or more levels.The multi-level page tables are tree-like structures to hold page table. The entries of the level-0 page table are pointers to… Read More »
In an operating system, deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process. For example, in the below diagram, Process 1 is holding Resource 1 and waiting for resource 2 which is acquired by process 2, and process 2… Read More »
Deadlock and Starvation both are the conditions where the processes requesting for a resource has been delayed for a long. Although deadlock and starvation both are different from each other in many aspects. 1. Deadlock : Deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another… Read More »
To understand system calls, first one needs to understand the difference between kernel mode and user mode of a CPU. Every modern operating system supports these two modes. In computing, a system call is the programmatic way in which a computer program requests a service from the kernel of the operating system it is executed on. A system… Read More »
Deadlock Detection and Deadlock recovery are important tasks of OS. If deadlocks are not avoided, then another approach is to detect when they have occurred and recover somehow. These are explained as following below. 1. Deadlock Detection : If resources have single instance : If cycle exist in the Resource Allocation Graph, then there exist deadlock in the… Read More »
A scheduler is a type of system software that allows you to handle process scheduling. There are mainly three types of Process Schedulers: Long Term, Short Term, Medium Term. These are explained as following below. Long Term or job scheduler : Long term scheduler is also known as job scheduler. It chooses the processes from the pool (secondary… Read More »
Process Synchronization is a way to coordinate processes that use shared data. Critical section is a segment of code that can be accessed by only one signal process at a certain instance in time. This section consists of shared data resources that need to be accessed by other processes. The entry to the critical section is handled by… Read More »
Dual-mode operation forms the basis for I/O protection, memory protection and CPU protection. Two modes are provided by the hardware – user and kernel mode. Mode bit is added to computer hardware to indicate the current mode. When system boots, hardware starts in kernel mode. The OS is loaded and then user process is started in user mode.… Read More »
The Operating system (OS) acts as a host for application programs that are run on the machine. Operating system (OS) is a software which acts as an interface between the end user and computer hardware. Every computer must have at least one OS to run other programs. In simple terms, an operating system is the interface between the… Read More »