Answer
Note:
The following information is for customers who have downloaded the ESRI Data & Maps for ArcGIS Server 10 ISO image files from the ESRI Customer Care site.
The complete ESRI Data & Maps for ArcGIS Server 10 collection is approximately 8GB and is too large for a single, reliable download. For convenience, the collection was broken up into three downloads.
Each download provides a set of map cache files and all the necessary source documents and Help documentation to publish map services referencing the ESRI Data & Maps for ArcGIS Server 10 map caches on ArcGIS Server.
If more than one ESRI Data & Maps for ArcGIS Server 10 ISO image file is downloaded, a small number of duplicate files (\source_documents\data and help) are included with all three ISO image file downloads.