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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-06031510-2089-55A1-98A2-9045D1D07E4E" xml:lang="en"><title>File

systems</title><shortdesc>This topic describes the file system concept.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>A file system operates within the file server to provide services which

deliver the required function to the client API. The <filepath>elocal.fsy</filepath> file

system, a core part of the operating system, drives the local media—ROM, RAM

and CF card. A <keyword>VFAT</keyword> file system is used in each case, which

maps directly onto the client API.</p>

<p>Other file systems may be implemented, for example to support remote

file systems over a network. Such file systems may be installed dynamically

without any reboot. They may also be uninstalled dynamically, and so free

up resources.</p>

<p>Installable file systems must present a Symbian platform native interface

for clients, no matter what the interface and specification of the remote

file system. This is trivial for Windows, OS/2 and DOS, since Symbian platform

maps these directly. For Unix, minor changes such as swapping directory separators

between <filepath>/</filepath> and <filepath>\</filepath> are needed. For

systems such as IBM's mainframes, and DEC's VMS, more radical mappings are

needed, to transform between the remote file system's record-based architecture,

and Symbian platform's byte-based architecture.</p>

</conbody></concept>