The ODBCINST initialization information is located in the HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI registry key. When you install an ODBC-compliant driver, ODBCINST.INI is automatically updated with a description of the driver.
This description includes:
The DBMS or data source associated with the driver
The drive and directory of the driver and setup DLLs (for some data sources, the driver and setup DLLs are the same)
Other driver-specific connection parameters
You do not need to edit the registry key directly to modify connection information. If your driver uses the information in the ODBCINST.INI registry key, the key is automatically updated when you install the driver. This is true whether the driver is supplied by Sybase or another vendor.