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The fork() and exec() System Calls If one thread in a program calls fork(), does the new process duplicate all threads, or is the new process single-threaded? Some UNIX systems have chosen to have two versions of fork(), one that duplicates all threads and another that duplicates only the thread that invoked the fork() system call. Signal Handling A signal is used in UNIX systems to notify a pro..

Thread Pools The general idea behind a thread pool is to create a number of threads at start-up and place them into a pool, where they sit and wait for work. When a server receives a request, rather than creating a thread, it instead submits the request to the thread pool and resumes waiting for additional requests. If there is an available thread in the pool, it is awakened, and the request is ..

Two primary ways of implementing thread library. 1) The first approach is to provide a library entirely in user space with no kernel support. 2) The second approach is to implement a kernel-level library supported directly by the operating system. Two general strategies for creating multiple threads 1) asynchronous threading : With asynchronous threading, once the parent creates a child thread, ..

Trend in system design is to place multiple computing cores on a single processing chip where each core appears as a separate CPU to the operating system. We refer to such systems as multicore, and multithreaded programming provides a mechanism for more efficient use of these multiple computing cores and improved concurrency. Example) Consider an application with four threads. Below is Single co..

A thread is a basic unit of CPU utilization; it comprises a thread ID, a program counter (PC), a register set, and a stack. Shares with other threads belonging to the same process its code section, data section, and other operating-system resources, such as open files and signals. Motivation Benefits Responsiveness - Multithreading an interactive application may allow a program to continue runni..

Sockets A socket is identified by an IP address concatenated with a port number. In general, sockets use a client – server architecture. All ports below 1024 are considered well known and are used to implement standard services. All connections must be unique. Therefore, if another process also on host X wished to establish another connection with the same web server, it would be assigned a port..