To use ODBC, the Access ODBC Driver needs to be installed. This can be obtained from Microsoft and is included with Microsoft Office. The installation programme (for example, for Microsoft Office) will copy the necessary drivers and the Jet Engine DLL into the appropriate Windows directories when the appropriate Data Access/ODBC options are selected.
With the Driver installed on the PC the ODBC Icon can be selected from the Control Panel and a Data Service Name set up for the desired MDB. This is used in the DSN= part of the connect string.
The Jet Engine DLL is quite large (1 MB) and the execution speed of the runtime (and your application) can be impacted if the Windows Virtual Memory Manager (VMM) swaps it out of memory. The next time an SQL is executed there will be short delay while the DLL is loaded back into memory. To force the VMM to keep the DLL in memory, design a simple dummy table with only one record and one field and set up a Cicode task that frequently (say every 10-15 seconds) calls a SELECT query based only on the dummy table. This has no significant effect on CPU load and keeps the DLL in memory.