Synchronization
In computer science, synchronization refers to one of two distinct but related concepts: synchronization of processes, and synchronization of data. Process synchronization refers to the idea that multiple processes are to join up or handshake at a certain point, in order to reach an agreement or commit to a certain sequence of action. Data synchronization refers to the idea of keeping multiple copies of a dataset in coherence with one another, or to maintain data integrity. Process synchronization primitives are commonly used to implement data synchronization.
Dealock
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.
The Critical Section Problem
The Critical Section Problem
Critical Section is the part of a program which tries to access shared resources. That resource may be any resource in a computer like a memory location, Data structure, CPU or any IO device.
The critical section cannot be executed by more than one process at the same time; operating system faces the difficulties in allowing and disallowing the processes from entering the critical section.
The critical section problem is used to design a set of protocols which can ensure that the Race condition among the processes will never arise.
Semaphore
In computer science, a semaphore is a variable or abstract data type used to control access to a common resource by multiple processes in a concurrent system such as a multitasking operating system. A semaphore is simply a variable. This variable is used to solve critical section problems and to achieve process synchronization in the multi processing environment. A trivial semaphore is a plain variable that is changed (for example, incremented or decremented, or toggled) depending on programmer-defined conditions.
Starvation
Starvation 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.
Read/Write structure to a file in C For writing in file, it is easy to write string or int to file using fprintf and putc, but you might have faced difficulty when writing contents of struct. fwrite and fread make task easier when you want to write and read blocks of data.
Arithmetic logic unit
In computing, an arithmetic logic unit (ALU) is a combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers.[1][2][3] This is in contrast to a floating-point unit (FPU), which operates on floating point numbers. It is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs).[4]
Banker’s algorithm
The Banker algorithm, sometimes referred to as the detection algorithm, is a resource allocation and deadlock avoidance algorithm developed by Edsger Dijkstra that tests for safety by simulating the allocation of predetermined maximum possible amounts of all resources, and then makes an “s-state” check to test for possible deadlock conditions for all other pending activities, before deciding whether allocation should be allowed to continue.
Deadlock prevention algorithms
In computer science, deadlock prevention algorithms are used in concurrent programming when multiple processes must acquire more than one shared resource. If two or more concurrent processes obtain multiple resources indiscriminately, a situation can occur where each process has a resource needed by another process. As a result, none of the processes can obtain all the resources it needs, so all processes are blocked from further execution. This situation is called a deadlock. A deadlock prevention algorithm organizes resource usage by each process to ensure that at least one process is always able to get all the resources it needs.
Deadlock avoidance
In deadlock avoidance, the request for any resource will be granted if the resulting state of the system doesn’t cause deadlock in the system. The state of the system will continuously be checked for safe and unsafe states.
In order to avoid deadlocks, the process must tell OS, the maximum number of resources a process can request to complete its execution.
The simplest and most useful approach states that the process should declare the maximum number of resources of each type it may ever need. The Deadlock avoidance algorithm examines the resource allocations so that there can never be a circular wait condition.