NAS4Free是一个免费开源网络附属存储软件，关于什么是NAS，请看百度百科的NAS词条。
NAS4Free可在在虚拟或普通硬件平台，用于在网络中共享存储数据。NAS是网络附属存储，4Free标识自由和开源。NAS4Free是中心化存储，易于访问使用的服务的简易快速实现方式，适用于各种网络协议和网络类型。
The NAS4Free operating system can be installed on virtually any hardware platform to share computer data storage over a computer network. 'NAS' as in “Network-Attached Storage” and '4Free' as in 'Free and open source', NAS4Free is the simplest and fastest way to create a centralized and easily-accessible server for all kinds of data easily accessed with all kinds of network protocols and from any network.
NAS4Free支持在Windows，Apple和类Unix系统间共享文件，支持ZFS v5000，软件RAID0，RAID5，磁盘加密，S.M.A.R.T / 电子邮件报告等，支持各种协议（见下面英文介绍）。NAS4Free可按照在闪存，U盘，固态硬盘，硬盘上，支持LiveCD启动和USB启动等。
NAS4Free supports sharing across Windows, Apple, and UNIX-like systems. It includes ZFS v5000 , Software RAID (0,1,5), disk encryption, S.M.A.R.T / email reports etc. with the following protocols: CIFS/SMB (Samba), Active Directory Domain Controller (Samba), FTP, NFS, TFTP, AFP, RSYNC, Unison, iSCSI (initiator and target), HAST, CARP, Bridge, UPnP, and Bittorent which is all highly configurable by its WEB interface. NAS4Free can be installed on Compact Flash/USB/SSD key, Hard disk or booted from a LiveCD/LiveUSB with a small usbkey for config storage.