CPU

The heart of every NAS is a computer that includes the central processing unit (CPU) and memory. The CPU is responsible for running the NAS OS, reading and writing data against storage, handling user access and even integrating with cloud storage if so designed. Where typical computers or servers use a general-purpose CPU, a dedicated device such as NAS might use a specialized CPU designed for high performance and low power consumption in NAS use cases.

Network Interface

Small NAS devices designed for desktop or single-user use might allow for direct computer connections, such as USB or limited wireless (Wi-Fi) connectivity. But any business NAS intended for data sharing and file serving will demand a physical network connection, such as a cabled Ethernet interface, giving the NAS a unique IP address. This is often considered part of the NAS hardware suite, along with the CPU.

Storage

Every NAS must provide physical storage, which is typically in the form of disk drives. The drives might include traditional magnetic HDDs, SSDs or other non-volatile memory devices, often supporting a mix of different storage devices. The NAS might support logical storage organization for redundancy and performance, such as mirroring and other RAID implementations -- but it's the CPU, not the disks, that handle such logical organization.

OS

Just as with a conventional computer, the OS organizes and manages the NAS hardware and makes storage available to clients, including users and other applications. Simple NAS devices might not highlight a specific OS, but more sophisticated NAS systems might employ a discrete OS such as Netgear ReadyNAS, QNAP QTS, Zyxel FW or TrueNAS Core, among others.