The Single-Tier ODBC Drivers for Oracle are a single component installed on a data-consuming machine - depending on the architecture in which the driver is deployed, either a client such as a desktop, a workstation or an application-server machine. No components need be installed on the database server.
The OpenLink Single-Tier Drivers for Oracle are a Type-B class of driver developed using the Oracle CLI.
The Oracle drivers for Versions 7, 8 and 9 require SQL*Net, Net-8 or Net-9 installed. For Oracle 10g and above, we use the Oracle Instant Client, which obviates the need for the RDBMS-specific comms layer.