You want to execute operations concurrently.

Use operation queues. Alternatively, subclass NSOperation and detach a new thread on the main method.

As mentioned in Recipe 5.12, operations, by default, run on the thread that calls the start method. Usually we start operations on the main thread, but at the same time we expect the operations to run on their own threads and not take the main thread’s time slice. The best solution for us would be to use operation queues. However, if you want to manage your operations manually, which I do not recommend, you can subclass NSOperation and detach a new thread on the main method. Please refer to Recipe 5.16 for more information about detached threads.