is a pair of client and server a pair of a master and worker?
is a pair of a master and worker a pair of client and server?
must a worker be created by its own master? In comparison, a server is often not created by a client.
must a worker have only one master, but not more than one masters? In comparison, a server can serve multiple clients. Thanks.
Not necessarily. In many practical architectures there is a pool of workers who are withdrawing request records from thread-safe queues and perhaps putting their results onto another queue. Instead of "master" and "slave," I'd use words like "producer" and "consumer."
A work-request that comes in might (like an order in a fast food restaurant) be split among many different specialized workers, each one of which is focused on his own "to-do list" and working asynchronously. (The "burger meister," the "fry guy," the "master of the milk shakes" and so on.) They are workers, who might be specialists, but they are not slaves.
Eventually, all the parts come together in the proverbial paper-bag, and the clerk hands it to you with a smile. Bon appetit!