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<!DOCTYPE concept
  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>