Mapping memory

Depending on the product that you are running, sample layouts and/or document type definition (DTD) files may be available in these locations:

• In <product installation directory>\plugins\com.ibm.debug.memorymap.<platform>.samples\samples, where <product installation directory> is the directory where you installed this product.
• In <product installation directory>\maps.

Predefined memory layouts are stored in XML files (one XML file for each layout, created using a text or XML editor). The XML file format provides for describing structures of predefined primitive type elements or nested layouts, where a layout element can point to another memory layout file. The layout file also specifies the length of the memory block to be laid out.

The size of a memory block that you monitor is determined by the size of the selected layout. If the specified memory block is protected or cannot be accessed, the display values will be shown as the string that is set as the padded string in the user preferences (by default, this is a number of "?"s).

Initially, the layout element and any sub-elements representing nested layouts are not populated (no sub-elements are generated yet). The first time you expand a layout element, it is populated according to the XML layout file. Populating the layout element means breaking the memory block into fragments corresponding to the layout elements specified in the XML. The values displayed for the layout sub-elements are formatted according to a default primitive type specified in the XML file.