Starvation and Deadlock are situations that occur when the processes that require a resource are delayed for a long time. However they are quite different concepts.Details about starvation and deadlock are given as follows −StarvationStarvation occurs if a process is indefinitely postponed. This may happen if the process requires a resource for execution that it is never alloted or if the process is never provided the processor for some reason.Some of the common causes of starvation are as follows −If a process is never provided the resources it requires for execution because of faulty resource allocation decisions, then starvation can ... Read More

Mutex and Semaphore both provide synchronization services but they are not the same. Details about both Mutex and Semaphore are given below −MutexMutex is a mutual exclusion object that synchronizes access to a resource. It is created with a unique name at the start of a program. The Mutex is a locking mechanism that makes sure only one thread can acquire the Mutex at a time and enter the critical section. This thread only releases the Mutex when it exits the critical section.This is shown with the help of the following example −wait (mutex); ….. Critical Section ….. signal (mutex);A ... Read More

Semaphores are integer variables that are used to solve the critical section problem by using two atomic operations, wait and signal that are used for process synchronization.The definitions of wait and signal are as follows −WaitThe wait operation decrements the value of its argument S, if it is positive. If S is negative or zero, then no operation is performed.wait(S) {    while (S

Process communication is the mechanism provided by the operating system that allows processes to communicate with each other. This communication could involve a process letting another process know that some event has occurred or transferring of data from one process to another. One of the models of process communication is the shared memory model.The shared memory in the shared memory model is the memory that can be simultaneously accessed by multiple processes. This is done so that the processes can communicate with each other. All POSIX systems, as well as Windows operating systems use shared memory.A diagram that illustrates the ... Read More

The shell is the command interpreter on the Linux systems. It the program that interacts with the users in the terminal emulation window. Shell commands are instructions that instruct the system to do some action.Some of the commonly used shell commands are −basenameThis command strips the directory and suffix from filenames. It prints the name of the file with all the leading directory components removed. It also removes a trailing suffix if it is specified.Example of basename is as follows −$ basename country/city.txtThis gets the name of the file i.e. city which is present in folder country.city.txtcatThis command concatenates and ... Read More

The loadable kernel modules in an operating system is an object file that contains code to extend the running kernel, which is also known as the base kernel. The loadable kernel modules are used to add support for file systems, hardware, system calls etc.An image that shows the loadable modules of the operating system is as follows −The different types of kernels in the operating system that may require loadable kernel modules are −MicrokernelA microkernel is the minimum software that is required to correctly implement an operating system. This includes memory, process scheduling mechanisms and basic inter-process communication.The microkernel contains ... Read More

The BIOS, operating system and hardware components of a computer system should all be working correctly for it to boot. If any of these elements fail, it leads to a failed boot sequence.System Boot ProcessThe following diagram demonstrates the steps involved in a system boot process −Here are the steps −The CPU initializes itself after the power in the computer is first turned on. This is done by triggering a series of clock ticks that are generated by the system clock.After this, the CPU looks for the system’s ROM BIOS to obtain the first instruction in the start-up program. This ... Read More

Loadable kernel modules in an operating system is an object file that contains code to extend the running kernel, which is also known as the base kernel. The loadable kernel modules are used to add support for file systems, hardware, system calls etc.A figure that shows the loadable modules of the operating system is as follows −Advantage of Loadable Kernel ModulesAn operating system would have to include all the systems that provided all anticipated functionalities in the base kernel if there were no loadable modules. This would lead to wastage of memory as most of those systems would not be ... Read More

Operating Systems have evolved over the years. So, their evolution through the years can be mapped using generations of operating systems. There are four generations of operating systems. These can be described as follows −The First Generation ( 1945 - 1955 ): Vacuum Tubes and PlugboardsDigital computers were not constructed until the second world war. Calculating engines with mechanical relays were built at that time. However, the mechanical relays were very slow and were later replaced with vacuum tubes. These machines were enormous but were still very slow.These early computers were designed, built and maintained by a single group of ... Read More

Many operating systems are not based on one model of the operating system. They may contain multiple operating systems that have different approaches to performance, security, usability needs etc. This is known as a hybrid operating system.The Hybrid operating system may allow one operating system to fulfil one set of requirements and the other operating system to fulfil the rest. For example, one of the operating systems may provide user interface, applications monitoring etc. while the other operating system may be a high-performance operating system that does not provide the same services as the first operating system.Features of Hybrid Operating ... Read More