Abstract: A method and apparatus for switching n data streams for input and output of the data streams by an n input, n output data store without data loss. The data store is divided into n separate storage arrays and each data stream is divided into n equal-sized pieces. Then, during each one of n separate time units, one data stream piece is written into a corresponding one of the storage arrays; or, one data stream piece is read from a corresponding one of the storage arrays. For each data stream, during each time unit i, where 1≦i≦n an ith data stream piece is written into an ith one of the storage arrays, or an ith piece is read from an ith storage array. During each jth time unit, where 1≦j≦n, one data stream piece Pij is written into an ith storage array, or one piece Pij is read from an ith storage array.