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diff --git a/c-user/dual-ported-memory/background.rst b/c-user/dual-ported-memory/background.rst new file mode 100644 index 0000000..3b6301e --- /dev/null +++ b/c-user/dual-ported-memory/background.rst @@ -0,0 +1,23 @@ +.. SPDX-License-Identifier: CC-BY-SA-4.0 + +.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) + +.. index:: dual ported memory, definition +.. index:: external addresses, definition +.. index:: internal addresses, definition + +Background +========== + +A dual-ported memory area (DPMA) is an contiguous block of RAM owned by a +particular processor but which can be accessed by other processors in the +system. The owner accesses the memory using internal addresses, while other +processors must use external addresses. RTEMS defines a port as a particular +mapping of internal and external addresses. + +There are two system configurations in which dual-ported memory is commonly +found. The first is tightly-coupled multiprocessor computer systems where the +dual-ported memory is shared between all nodes and is used for inter-node +communication. The second configuration is computer systems with intelligent +peripheral controllers. These controllers typically utilize the DPMA for +high-performance data transfers. |