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<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-C13DFF33-7C54-5113-9277-CAD96215F075" xml:lang="en"><title>RAM
Zones</title><shortdesc>A RAM zone is a physically contiguous section of RAM address space
that has a preference value and a unique ID.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p> A base port must define the RAM zones for a phone. The Kernel uses RAM
zones to decide how to allocate RAM pages so that: </p>
<ul>
<li id="GUID-B407EC83-9493-5D76-9CAF-EFA86F06870E"><p>only the necessary parts
of a device’s RAM ICs are powered and refreshed. This may reduce power consumption. </p> </li>
<li id="GUID-77601E75-5D27-5283-9693-329F29370FE0"><p>pre-determined regions
of physically contiguous RAM can be used for a specific function when required.
For example, a buffer required by a camera peripheral. </p> </li>
</ul>
<p>The system attempts to allocate memory in a preferred RAM zone. A preferred
RAM zone is a zone that has a lower preference value than another. </p>
<p>All methods that perform operations on a specific RAM zone take the unique
ID of the RAM zone as a parameter. </p>
<p>RAM zones are specified only once during the boot process by the base port.
The base port must do this in its ASSP/Variant in its implementation of the <xref href="GUID-A83A7C3C-7DC0-3B9C-842F-70FCC751365D.dita#GUID-A83A7C3C-7DC0-3B9C-842F-70FCC751365D/GUID-63F2135B-4264-3B3B-9B68-656A89BF7EE9"><apiname>Asic::Init1()</apiname></xref> function. </p>
</conbody><related-links>
<link href="GUID-26621CA5-B686-53FB-AF3E-96CDD38C8520.dita"><linktext>Physical
RAM                 Defragmentation</linktext></link>
<link href="GUID-C376486D-B9BF-5D00-8B1A-1527FC1F83AD.dita"><linktext>RAM Zone
Tutorial</linktext></link>
</related-links></concept>