What service allows multiple computers to collaborate on a single task on an Apple Mac OS X/macOS server?

The service that allows multiple computers to collaborate on a single task on an Apple Mac OS X/macOS server is distributed computing with Xgrid. Xgrid is a framework that enables the distribution of processing tasks across multiple computers within a network. This system harnesses the computing power of multiple machines, allowing them to work together on a single project. By breaking down a large task into smaller parts, Xgrid efficiently assigns these tasks to available computers, thus speeding up the processing time and increasing productivity for tasks such as data analysis, rendering, or any computationally intensive jobs.

Remote File Access facilitates the sharing of files across devices but does not contribute to the collaborative processing of tasks. Server virtualization allows multiple virtual servers to run on a single physical server, improving resource utilization and flexibility but not facilitating collaboration on a single task among separate computers. Network Load Balancing is designed to distribute network traffic across multiple servers to ensure that no single server becomes overwhelmed, but it does not inherently enable collaborative task processing. Therefore, distributed computing with Xgrid is the unique solution among the options provided that specifically supports the collaboration of multiple computers on a single task.