NAS operating systems can be roughly divided into three categories

NAS is becoming increasingly popular, and our company has launched the following new NAS products: N2940-17 * 17- Single Network 4-Disk NAS Host, N150-17 * 17-3 Network 4-Disk NAS Host, N150-17 * 17-3 Network 8-Disk NAS Host, how should we distinguish between several major categories

Category 1: Operating systems for off-the-shelf NAS products with integrated hardware and software

These include systems from brands such as Synology, QNAP, TerraMaster, ZSpace, Green Union, WanYou, Asustor, and Hikvision. Among them, there are "cracked versions" of Synology and QNAP systems, enabling the deployment of the operating systems directly without purchasing the branded hardware.

Category 2: Pure software operating systems
These consist of both paid and free options that support self-hosted deployment on various hardware, such as Unraid, TrueNAS Scale, FreeNAS (TrueNAS Core), OMV (OpenMediaVault), IstoreNAS, ZimaOS, and XigamaNas.

Category 3: Native systems integrated with virtualization
These are Linux-based systems supplemented by virtualization and containerization technologies, forming a visualized server management system capable of deploying various services. Examples include UmbrellaOS and Cosmos-Server. Meanwhile, virtualization platforms like Proxmox VE (PVE), VMware ESXi, and Hyper-V are also included in this category.

Among the three categories of NAS systems mentioned above:
- In the first category, "black Synology" and "black QNAP" (unofficial installations on non-branded hardware) are available.
- In the second category, Unraid, which adopts a subscription model, also has a "cracked version."
- The remaining systems generally support free deployment and usage.