Data-storage Systems are everywhere, from handheld devices and IoTs, all the way to large cloud systems. Storage systems hold all of the world's data persistently, estimated at hundreds of zettabytes generated annually and growing. Storage systems must store data reliably for many years; they can be fairly complex and range widely in capacity, cost, and speed. This course will cover the entire storage stack, from low-level storage devices such as hard disks and SSDs, through operating system layers (e.g., block drivers, virtualization layers, and file systems), all the way to network, distributed, and cloud-based storage systems. The course will discuss the various design and configuration tradeoffs for data-storage systems: capacity, cost, performance and latency, security, energy consumption, availability, and reliability. Students taking the course will be able to configure and optimize storage arrays of varying sizes and needs.