Area of memory assigned to a particular transaction and any modules called from there.
ABAP memory does not depend on the ABAP program that generates it during a transaction. This means that any object stored there can be read by any ABAP program during the same transaction.
In contrast to ABAP memory, which exists only for the life of one transaction, there is also global SAP memory, which extends beyond transaction limits.
Global, user-related memory that extends beyond transaction limits.
Access to the SAP memory is via SPA/GPA parameters.