Traditional OSes are system software, including programs that manage computing resources, control peripheral devices, and provide software abstraction to the application software. Traditional OS functions are therefore to manage processes, memory, CPU time,file system, and devices. This is often implemented in a modular and layered fashion, including a lower layer of kernels and a higher layer of system libraries.Traditional OSes are not suitable for WSNs because WSNs have constrained resources and diverse datacentric applications, in addition to a variable topology.WSNs need a new type of operating system, considering their special characteristics. There are several issues to consider when designing sensor network OS.