Cascade Historian

This software review is for Cascade Historian, an event-driven data storage program primarily used for persistent time-sequence data sets derived from process data. In terms of the software's features and benefits, aside from providing storage, the Historian also offers a historical query facility that is suitable for generating graphs and tabular output used for export to other analysis programs. Additionally, other programs can also send data to the Cascade Historian by linking the API library and making the appropriate function calls.

The data storage mechanism within the Cascade Historian can maintain any number of simultaneous time histories with one for each configured process point. Moreover, the data for each point is stored in one or more files, allowing for the removal of stale data or offline archival of old data. These files are either numbered in increasing numerical order or dated, and when using dated files, the Cascade Historian automatically begins logging to a new file at midnight.

The Cascade Historian records data by event and only writes to disk when a data change event occurs for a point. This saves disk space when the process point is idle and captures even very short duration events when the point is changing. This method is more efficient and more accurate than a sampling historian. The Cascade Historian will not reorder out of sequence data. The data is stored on disk in fixed-length binary records to minimize disk space, with a time resolution of nanoseconds. These files can easily be read by any custom program as well as by the Cascade Historian.

Any process may request data from the Cascade Historian. The software maintains a configurable in-memory cache for each point being recorded, so queries of recent data will not require disk access. If the request cannot be satisfied from the in-memory cache, the disk files related to the point will be consulted for the data to satisfy the request. The requests can take one of the following forms: Raw Data, Periodic Data, Relative Interpolation, or Periodic Relative Interpolation.

Lastly, the Cascade Historian has been built to allow quick addition of other forms of historical query. Overall, the software's features and benefits make it an excellent option for those in need of a reliable and efficient solution for event-driven data storage.