Data Compression

In order to reduce the amount of data to be sent without reducing the amount of information and thus enhance the performance, a compression method derived from the Run Length Encoding method can be used. It utilizes the fact, that data of two consecutive samples in a buffer may not vary in parts. Thus knowing what parts of a previously sent buffer are equal in conjunction with the varying data, a recipient can reconstruct the next buffer without the need to receive the whole buffer. After sending the first buffer uncompressed, the logger constructs the compressed buffer by comparing user-specified units of data (e.g. every byte, every 8 byte etc.) one after another. The logger counts the amount of data units (called Compression Compare Width) that are equal and places this information in the buffer instead of the data. Dependent on the kind of data this can lead to a data saving or overhead. To decide whether a compression is purposeful or not the user is provided with a data compression saving value, which can be found on the Online-tab of every stream dialog window. A positive value indicates saving and a negative value indicates overhead.