Stream Buffer

Stream Buffering : Buffer X [minutes/blocks] of stream data
The stream buffer is an important part of many of Scream's functions, and it's use and implications should be well understood. In simple terms, it sets the amount of memory used to buffer each stream. This buffer is used by many parts of scream:

  1. When a WaveView window needs to be re-drawn, only the data in this buffer can be viewed. Similarly, when a status window is opened, only the buffered status blocks will be displayed in the window.
  2. The Auto-print facility of a WaveView window is, in effect, a re-draw of the window to a printer device. This means that if you have, for example, an auto-print set for every 2 hours, and a WaveView window with 2 hours width, then you need to ensure you have AT LEAST 2 hours of stream buffering in order for the auto-print to include all the data you want.
  3. The display buffer is used to re-sort out-of-sequence data as it arrives, and before it is written to file. Out of sequence data can occur from network outages or from a digitizer in Adaptive mode.
  4. If repeated data is received (e.g. duplicate network packets, or a repeated replay), the Stream buffer ensures that duplicates are recognised and discarded. If the data is not already in the stream buffer, it will be written to file, with the risk of duplicating data already on file.
The choice of setting for the stream buffer depends on several parameters. The general rule is that you should select as large a value as possible, without exceeding the memory limitations of the computer.
There are two different ways of expressing the buffering size: by time in minutes, or by number of blocks.

See Also: Setup, WaveView Windows, Display Options