TDMS Flush

File Buffering with TDMS Files

When a TDMS node writes data to a .tdms file, the data waits in a buffer until the buffer fills up or until you close the file. Buffering holds more data values in memory and allows you to wait and flush data to disk once, rather than continuously writing data. This both improves performance and causes the .tdms file to have fewer segments and be less fragmented. Files with fewer segments are more compact and take less time to open.

Buffering can occur at the channel layer, in the operating system (OS) file system, or in the TDMS disk cache. The layer at which buffering occurs depends on the property you set using the node. For example, the NI_MinimumBufferSize property determines the number of data samples to buffer at the channel layer. The disable buffering input of TDMS nodes determines whether to disable system buffering, which occurs in the OS. When the disable buffering input is True, this product disables system buffering and buffering occurs in the TDMS disk cache. The NI_DiskCacheSize property determines the amount of cache size in the TDMS disk cache to allocate for data. This property is valid only if the disable buffering input is True.

To write all buffers directly to the TDMS file, use the TDMS Flush node.