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<task id="GUID-3D8B134E-3C2F-5BAF-82AB-0AB786A5D22D" xml:lang="en"><title> Directory

Cache Tutorial</title><shortdesc>Describes how to configure the directory cache in a FAT file system

enabled drive. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

<prereq id="GUID-E3BEB74D-79C7-59A9-9366-CCD8B52DB7F8-GENID-1-7-1-14-1-1-9-1-7-1-7-1-3-1"><p>Before you start,

you must: </p> <ul>

<li id="GUID-41E9D4BC-974F-5046-8FC1-E3C67298C5AA"><p>have the knowledge of

the <xref href="GUID-AFFC4002-3A06-5458-A4D9-1E0AEDB8C534.dita">FAT file system</xref>  </p> </li>

<li id="GUID-2F012BA2-6AF2-56D6-852E-6042618ECD8F"><p>have the knowledge of

the <xref href="GUID-AFFC4002-3A06-5458-A4D9-1E0AEDB8C534.dita#GUID-AFFC4002-3A06-5458-A4D9-1E0AEDB8C534/GUID-86BEEEF5-F4F0-50AD-AF29-0A0277455BDB">directory

cache</xref>  </p> </li>

<li id="GUID-88E374C2-B670-53DE-8677-7712ECE3EB8F"><p>have the knowledge of

the <xref href="GUID-AFFC4002-3A06-5458-A4D9-1E0AEDB8C534.dita#GUID-AFFC4002-3A06-5458-A4D9-1E0AEDB8C534/GUID-7675348A-9D74-54DB-A09A-0537AD4D6CA5">global

cache manager</xref>. </p> </li>

</ul> </prereq>

<context id="GUID-6799E3F3-353E-5C00-A38C-D32F888392AA-GENID-1-7-1-14-1-1-9-1-7-1-7-1-3-2"><p>The developers

can configure the directory cache memory with a dynamic range. The memory

allocation for directory cache on a drive depends on the available global

cache memory. The global cache manager allocates memory to various cache memory

on different drives. The directory cache for a drive can be configured with

a dynamic range in the <filepath>estart.txt</filepath> file. The dynamic range

configuration consists of two values : </p> <ol id="GUID-166C832A-5B33-5271-AABD-A56EC49A61A3">

<li id="GUID-4191D5E1-0A2E-5C0D-B1C6-FE49F5C24CE4"><p> <codeph>FAT_DirCacheSizeMin</codeph> specifies

the minimum size of global cache to be allocated to the directory cache on

a drive. </p> </li>

<li id="GUID-E6941E15-9549-56B8-8F62-7BAAAD7DD90D"><p> <codeph>FAT_DirCacheSizeMax</codeph> specifies

the maximum size of the global cache to be allocated to the directory cache

of a drive. </p> </li>

</ol> <p>The minimum size of the directory cache is permanently reserved during

the file server startup time. The maximum memory allocation depends on the

available system memory and hence not guaranteed under low memory conditions. </p> <p>The

size of the cache memory is specified in Kilobytes. The default value for

both the parameters is 128 Kilobytes. </p> </context>

<steps id="GUID-67EA65BE-4457-57F5-B4F1-6A7A2F41354D">

<step id="GUID-EBD3AEBE-54CB-53AA-9014-E2378A857221"><cmd>Open the estart.txt

file </cmd>

<info><p>to configure the directory cache.</p> </info>

</step>

<step id="GUID-B24F2606-491F-5888-A025-3B5F0F3D4D9B"><cmd/>

<info>Create a new entry for a drive, say for example drive D: </info>

</step>

<step id="GUID-015BE3C2-6891-5BFC-979B-EBC7CF7E4590"><cmd/>

<info>Enter the minimum size of the directory cache to be allocated to the

parameter <codeph>FAT_DirCacheSizeMin</codeph>  </info>

<info>The value is specified in Kilobytes </info>

</step>

<step id="GUID-D6EF2F51-44D6-57EF-9614-6B7AB8D43848"><cmd/>

<info>Enter the maximum size of the directory cache that can be allocated

when available to the parameter <codeph>FAT_DirCacheSizeMax</codeph>  </info>

<info>The value is specified in Kilobytes. </info>

</step>

<step id="GUID-6EE5BE56-FD6E-523D-947D-2DCA5D4C0191"><cmd/>

<info>Repeat steps 2-4 for other drives. </info>

</step>

<step id="GUID-A98147EC-F076-5A27-B7D4-AAA0A87E70FC"><cmd/>

<info>Save and close the estart.txt file </info>

</step>

<step id="GUID-9D9F272C-F1F1-58F4-AB8B-672AD09ECA16"><cmd/>

<info>Build the ROM with the modified estart.txt file </info>

</step>

</steps>

<example><p> The sample entry for drive D is shown below: </p><codeblock xml:space="preserve">[DriveD]

FAT_DirCacheSizeMin  128

FAT_DirCacheSizeMax  256</codeblock></example>

</taskbody><related-links>

<link href="GUID-DC0BF2A3-613B-595C-BF47-07F29E2A7893.dita"><linktext>Leaf Directory

Cache Configuration                 Tutorial</linktext></link>

</related-links></task>