Limitations of 64bit Data Access on Windows
Some database do not yet have 64bit Windows APIs drivers, preventing native 64bit access from Windows. The following is a list of datasources with such limitations.
If the data is on another server, VMS for example, the 64bit Client component will use TCP/IP to communicate to the server component on another platform, and results in no limitations. If the data being access is on a non-Windows system, or the Enterprise Server Service is being used on Windows, there is no 64bit limitation.

Data Source | 64bit Data Access Limitation
ADABAS | ADABAS not currently available on 64bit Windows. CONNX can provide access to these data sources from 64bit applications through the 32bit CONNX Enterprise Server Service.
DataFlex/PowerFlex | 64bit Windows Dataflex/Powerflex API not available. CONNX can provide access to these data sources from 64bit applications through the 32bit CONNX Enterprise Server Service.
C-ISAM | 64bit Windows C-ISAM API not available. CONNX can provide access to these data sources from 64bit applications through the 32bit CONNX Enterprise Server Service.
D-ISAM | 64bit Windows D-ISAM API not available. CONNX can provide access to these data sources from 64bit applications through the 32bit CONNX Enterprise Server Service.
Microsoft Access & Excel & Word | 64bit ODBC & OLE DB Providers for these data sources not available. CONNX can provide access to these data sources from 64bit applications through the 32bit CONNX Enterprise Server Service.
Microfocus & RM Cobol | 64bit Windows server component not available. CONNX can provide access to these data sources from 64bit applications through the 32bit CONNX Enterprise Server Service.