Which layer contains orders and data which are being modified?

The Order Memory Layer is responsible for holding orders and data that are actively being modified. This layer is designed to provide a fast, in-memory representation of orders, allowing for quick access and alterations as needed. It facilitates the processing of ongoing transactions and updates, enabling real-time adjustments to the orders before they are finalized or persisted.

In contrast, the Order Persistence Layer is where finalized and stable order data is stored, ensuring long-term data integrity and availability. The Kernel Layer operates on a more fundamental level, providing essential support and services to all other layers but does not specifically manage orders or their current states. The Service Layer serves as an intermediary, offering functionality and operations to interact with data across multiple components but is not directly tied to the modification of orders themselves.

Thus, the correct understanding of the Order Memory Layer's role clarifies why it is designated for managing the active state of orders and the modifications being made to them.