Reference Work Entry

Encyclopedia of Database Systems

pp 1899-1900

Network Attached Secure Device

  • Kazuo Goda


NASD; Object-based Storage Device; OSD


A Network Attached Secure Device (often abbreviated to NASD) is a networked storage device which offers object-level storage accesses. NASD was first explored in a research project of the same name, which started at Carnegie Mellon University in 1995. NASD is now more often called Object based Storage Device (shortened to OSD).

Key Points

NASD is an approach of decoupling only low-level functions of file systems from NAS devices. A NASD manages only stored objects, each of which is identified with a unique file descriptor, and their additional information such as metadata and attributes, whereas a central policy server manages higher-level information which is used for name space management and authorization. A bunch of NASDs, with the assistance of the central policy server, can together work as a file store. This may look similar to NAS at a glance, but the difference is that most commands and data are ...

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