As a new field, MLSys does not yet have a universally agreed definition. Based on what we discussed, here is a concise one we will use to guide us through the book:

Definition: Machine learning systems (MLSys) is the engineering discipline focused on designing and implementing software that manages hardware resources to run machine learning models efficiently.

In this definition, we focus on efficiency because it is the core challenge of MLSys. We scale up the system to multiple machines with multiple GPUs, and make it reliable enough to run large machine learning workloads more efficiently. This definition will guide us through the book.