The scratch directory is an integral part of the inner workings of the eDiscovery Platform (eDP).  Some of the uses of the scratch directory are proprietary and the details can not be discussed publicly.  In general the scratch directory is a catch all working directory of information that can not easily be categorized and is used as a holding place for information on its way to a more permanent location. Below are some of the functions used by the eDP scratch folder:

•     Reviewer cache
•     System configuration information
•     Temp space
•     Third party temp space
•     Reporting information
•     Logging information
•     Database information
•     Some maintenance batch information

Note:
The list above is not intended to be comprehensive and changes dynamically with use of the product.

The scratch directory (for example D:\CW\VXX\scratch) will grow and change shape with it's subdirectories over the product life cycle.