Data storage system connectors are described for a parallel array of dense memory cards that allow high airflow. In one example, a connector has a horizontal plane board having a plurality of memory connectors aligned in a row and a plurality of external interfaces, a plurality of memory cards, each having an edge connector at one end of the memory card to connect to a respective memory connector of the board, each memory card extending horizontally parallel to each other memory card and extending vertically and orthogonally from the board, and a plurality of interface connectors each to connect an edge connector to a respective board connector, the interface connectors extending horizontally from the one end of the memory cards and vertically to the respective plane board connector.