Background vs Foreground Process
Background jobs run in a background work process that is different from dialog work processes. Background processing lets you move long running or resource-intensive program runs to times when the system load is low.
Here are the few points for consideration:
1. Limited Run Time: The Dialog work process has a run-time limit that prevents users from interactively running especially long reports. By default, the system terminates any dialog work process in a transaction that exceeds 300 seconds. Although this limit can be changed by Basis consultants but this is recommended. And if we talk about Background work process, there is no such limit applies to it.
2. Background work processes allocate memory differently than dialog work processes so that background work processes can become as large as they need to in allocated memory to allow for processing large volumes of data.
Read Here for More SAP ABAP Interview Questions