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+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-4ADDC0D4-F784-5023-BD82-F6223C8DC79E" xml:lang="en"><title>File Systems
+Overview</title><shortdesc>Provides several common file system implementation. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-B12E9720-673F-57FB-AF27-B0C2F5D1DDDA"><title>Purpose</title> <p>Provides
+file system implementations —<i>file server fsy plug-ins</i> — for devices
+that are reasonably expected to be used on a Symbian platform device. The
+file systems implement a storage and access format most appropriate to the
+media. Please see a file system's guide for its specific purpose. </p> </section>
+<section id="GUID-0AB0FA58-037F-542D-8BBB-D1E9661202FB"><title>Architecture</title> <p>The
+File Systems collection provides several kinds of file system implementations.
+File system binaries are built as <xref href="GUID-BB9760B4-4F3F-5326-81FB-B644C82F0E65.dita">FSY</xref> plugins
+that are loaded (added and mounted) by the file server; either at startup
+or as required such as when a device is physically attached to the phone (inserting
+a memory card into the card slot). </p> <p>The file server uses these implementations
+to access data on different media. </p> </section>
+<section id="GUID-6CACBD32-7E8A-5266-96D0-C2C2D82BC866"><title>Description</title> <p>The
+File Systems collection consists of a series of file server plugins, one for
+each file system. The various systems are loaded into a file server instance.
+Different devices use different file systems based on the characteristics
+of the storage medium. </p> <p>The following table lists several file systems
+and the different media that use them. </p> <p>The ROM file system is implemented
+as part of the file server component. The other files systems are implemented
+as separate file server plugins, which may be loaded using ESTART or as part
+of a mounting operation. </p> <p>All file system plugins files have .fsy extensions. </p> </section>
+<section id="GUID-952FDE22-385B-5048-A546-B57A79F90B48"><title>File System
+Summary</title> <p>The following file system plug-ins are provided: </p> <ul>
+<li id="GUID-5E4EAEEA-CA8B-5AE2-9D52-751CF3F921F0"><p><xref href="GUID-596E9D8B-7E75-5644-B4DC-6D657BE00A8B.dita">Composite
+File System</xref> (<filepath>ecomp.fsy</filepath>): The Composite File System
+for NAND flash devices presents a single drive Z: to the File Server that
+layers thinly over both the core ROM and the ROFS file systems. It redirects
+File Server requests to the core ROM or ROFS as required. See <xref href="GUID-775B5858-4358-5195-B580-7C16AE4981C3.dita">Flash
+Translation Layer Technology</xref> for more information on why this is required. </p> <p>This
+unifies the file systems for flash devices (ROM, ROFS and FAT file systems)
+into a common file system that is used with drive <filepath>Z:</filepath>.
+The file server will direct requests to the required file system as required. </p> </li>
+<li id="GUID-82C41045-11E9-5FC9-AE1E-7626CE45EA61"><p><xref href="GUID-CDB35952-5EE3-5643-BA0A-341FE0FF1A02.dita">FAT
+File System</xref> (<filepath>efat.fsy</filepath> or <filepath>elocal.fsy</filepath> when
+built for an emulator target.) : The FAT File System implements a file system
+that supports the VFAT standard. This is used for user data storage on NAND
+Flash, internal RAM drives, and removable media. </p> <p>This is the file
+system that was originally used by IBM PCs and is an industry standard for
+file systems. It is supported by all operating systems that execute on PCs.
+Symbian platform FAT only supports FAT12 and FAT16 types. </p> </li>
+<li id="GUID-35A95C58-10C0-5503-A898-CB11AF121A77"><p><xref href="GUID-0988F387-5F26-512E-BDA4-D5800EEC2A77.dita">FAT32
+File System</xref> (<filepath>efat32.fsy</filepath>): The FAT32 File System
+implements the enhanced version of the FAT file system standard that includes
+FAT32 support. </p> <p>The FAT32 file system is an update of the industry
+standard FAT file system. The Symbian platform FAT32 file system supports
+the FAT12, FAT16 and FAT32 file systems. </p> </li>
+<li id="GUID-E48530A9-A7BE-5EB1-B2F4-70779963B898"><p><xref href="GUID-15DD2080-83D6-5DE0-8B75-D4A5934C8C91.dita">ISO9660
+File System</xref> (<filepath>iso9660.fsy</filepath>): The ISO9660 File System
+implements a ISO9660 file system, that reads CDROM and DVD-ROM. This is only
+for the internal X86 port. </p> <p>The ISO9660 is an internationally agreed
+standard for the file system used by CD-ROM and DVD-ROM media. </p> <p> <note> ISO9660
+is for Symbian internal use only. </note> </p> </li>
+<li id="GUID-19C89E46-95EC-5F0D-AF66-ADB94A2ED408"><p><xref href="GUID-6FD18A95-2530-565C-8C92-E893649F2E59.dita">LFFS
+File System</xref> (<filepath>elffs.fsy</filepath>): The LFFS File System
+provides data storage on NOR type flash memory, and is portable to a wide
+range of Flash devices. </p> <p>LFFS is designed specifically to be used with
+NOR flash and has the ability to protect itself against power loss. </p> </li>
+<li id="GUID-9A1088B0-2928-5F1E-A73A-FE40254BB987"><p><xref href="GUID-57C0B4C9-255A-50CD-8E99-DD1A754060C0.dita">NTFS
+File System</xref> (<filepath>ntfs.fsy</filepath>): The NTFS File System provides
+read-only support for the NTFS file system standards. This is only for the
+internal X86 port. </p> <p>This is the file system for Windows NT, Windows
+2000, Windows-XP, Windows Server 2003, Windows Server 2008 and Windows Vista. </p> <p> <note> NTFS
+is for Symbian internal use only. </note> </p> </li>
+<li id="GUID-776918FD-4408-50D6-BEB2-9B1D991C1E97"><p><xref href="GUID-466628A1-80BB-57E7-8315-CD9E0A95CDC3.dita">ROFS
+File System</xref> (<filepath>erofs.fsy</filepath>): The Read-only File System
+(ROFS) supports a ROM-structured local file system that can be located on
+NAND flash, or other media, where executables are not executed in place (non-XIP). </p> <p>ROFS
+stands for Read Only File System and is used for accessing code storage on
+media that cannot be executed in that media (otherwise known as non-XIP storage),
+for example NAND flash. </p> </li>
+<li id="GUID-2E0072DF-6234-5D61-BB44-0F6DE6D062CF"><p><xref href="GUID-EB6CA066-B567-5542-9D41-183B27A70B82.dita">ROM
+File System</xref> (No FSY, ROM is the default file system build defined by <filepath>f32.iby</filepath>):
+The ROM file system is used to access the "core ROM image": this contains
+files that are copied from NAND Flash storage into RAM on boot. </p> <p>This
+is the file system that is used when the phone boots up. </p> </li>
+<li id="GUID-FC28E385-C8D1-5E90-B075-B8FA09FA09F5"><p><xref href="GUID-61BAA598-4D13-5859-8751-DA949744E27F.dita">USB
+Mass Storage File System</xref> (<filepath>msfs.fsy</filepath> and possibly <filepath>msfs_db.fsy</filepath>,
+depending on configuration): The USB Mass Storage File System is provided
+to support a licensee-provided USB mass storage application, which allows
+a desktop host computer access to a FAT-formatted drive on the phone. </p> <p>The <xref href="GUID-F3C8EB83-EBB3-5347-89B0-9A86D1864D12.dita">USB Mass Storage Server</xref> is
+used when a USB memory device is connected directly to the device executing
+Symbian OS. </p> <p>The <xref href="GUID-FA0A6825-88A8-549A-B360-E7D74EE79CF1.dita#GUID-FA0A6825-88A8-549A-B360-E7D74EE79CF1/GUID-BD5162E2-0D9C-5756-9804-556595330043">USB
+Mass Storage File System</xref> is used when the media on the device is accessed
+by an external device i.e. a PC when it is in "USB mass storage" mode. </p> </li>
+</ul> </section>
+<section id="GUID-2C14C280-9442-462A-BE5A-8C49A96FB8E4"><title>Using File
+System Plug-ins</title> <p>The file systems are used to allow kernel access
+to data on a media storage device such as Flash, MMC cards, SD cards, etc.
+A file systems FSY plug-in must be added to the file server and mounted before
+the kernel is granted access. </p> <p>Accessing a file system specific device
+requires: </p> <ul>
+<li id="GUID-5E8C4326-5A6F-51D7-9C84-8AF5F6BC36AF"><p>Adding a file system
+to the file server using <xref href="GUID-E263C747-946F-35AA-9F1D-41833BD350FC.dita#GUID-E263C747-946F-35AA-9F1D-41833BD350FC/GUID-51353BE2-9133-39F5-83F3-A5DB88D858CA"><apiname>RFs::AddFileSystem()</apiname></xref>  </p> </li>
+<li id="GUID-DBC20D4D-D358-5668-B9D8-BDF68A441A7E"><p>Mounting the file system
+using <xref href="GUID-E263C747-946F-35AA-9F1D-41833BD350FC.dita#GUID-E263C747-946F-35AA-9F1D-41833BD350FC/GUID-0754C075-92B6-37B3-8959-61D8D65DB491"><apiname>RFs::MountFileSystem()</apiname></xref>  </p> </li>
+</ul> <p>The file server handles all requests to access a mounted file system. </p> </section>
+</conbody><related-links>
+<link href="GUID-9E92EE30-F2E2-5F28-BB2A-391C09EC69D2.dita"><linktext>Using ECom</linktext>
+</link>
+<link href="GUID-F3BD37EC-0CCB-5859-908F-215E22C9FC20.dita#GUID-F3BD37EC-0CCB-5859-908F-215E22C9FC20/GUID-143780ED-4A23-5E72-A923-F605172EC8B5">
+<linktext>File Server</linktext></link>
+</related-links></concept>
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