Synchronous versus Asynchronous File Operations

You can read and write TDMS data either synchronously or asynchronously. The terms synchronous and asynchronous here do not define whether a hardware connection shares a common clock or timebase. Instead, these terms refer to how the TDM Streaming Library functions behave according to the calling threads.

• Synchronous I/O—TDMS synchronous read and write functions start a file I/O operation and wait for the I/O request to complete before the function returns. Because the function waits and does not return, your application cannot start a new I/O operation or execute additional code. When your application makes many I/O operations, the processor might spend almost all its time waiting idly for the I/O operations to complete.
• (Windows) Asynchronous I/O—TDMS asynchronous read and write functions start a file I/O operation and return without waiting for the I/O request to complete. Because the function returns without waiting, your application can initiate additional I/O operations or execute additional code. You can use this mode to improve the throughput, latency, or responsiveness of your TDMS application.

Related Information

TDM Data Model

TDM versus TDMS