1 <?xml version="1.0" encoding="utf-8"?>

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     7     Nokia Corporation - initial contribution.

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    10 <!DOCTYPE concept

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

    12 <concept id="GUID-4ADDC0D4-F784-5023-BD82-F6223C8DC79E" xml:lang="en"><title>File Systems

    13 Overview</title><shortdesc>Provides several common file system implementation. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <section id="GUID-B12E9720-673F-57FB-AF27-B0C2F5D1DDDA"><title>Purpose</title> <p>Provides

    15 file system implementations —<i>file server fsy plug-ins</i> — for devices

    16 that are reasonably expected to be used on a Symbian platform device. The

    17 file systems implement a storage and access format most appropriate to the

    18 media. Please see a file system's guide for its specific purpose. </p> </section>

    19 <section id="GUID-0AB0FA58-037F-542D-8BBB-D1E9661202FB"><title>Architecture</title> <p>The

    20 File Systems collection provides several kinds of file system implementations.

    21 File system binaries are built as <xref href="GUID-BB9760B4-4F3F-5326-81FB-B644C82F0E65.dita">FSY</xref> plugins

    22 that are loaded (added and mounted) by the file server; either at startup

    23 or as required such as when a device is physically attached to the phone (inserting

    24 a memory card into the card slot). </p> <p>The file server uses these implementations

    25 to access data on different media. </p> </section>

    26 <section id="GUID-6CACBD32-7E8A-5266-96D0-C2C2D82BC866"><title>Description</title> <p>The

    27 File Systems collection consists of a series of file server plugins, one for

    28 each file system. The various systems are loaded into a file server instance.

    29 Different devices use different file systems based on the characteristics

    30 of the storage medium. </p> <p>The following table lists several file systems

    31 and the different media that use them. </p> <p>The ROM file system is implemented

    32 as part of the file server component. The other files systems are implemented

    33 as separate file server plugins, which may be loaded using ESTART or as part

    34 of a mounting operation. </p> <p>All file system plugins files have .fsy extensions. </p> </section>

    35 <section id="GUID-952FDE22-385B-5048-A546-B57A79F90B48"><title>File System

    36 Summary</title> <p>The following file system plug-ins are provided: </p> <ul>

    37 <li id="GUID-5E4EAEEA-CA8B-5AE2-9D52-751CF3F921F0"><p><xref href="GUID-596E9D8B-7E75-5644-B4DC-6D657BE00A8B.dita">Composite

    38 File System</xref> (<filepath>ecomp.fsy</filepath>): The Composite File System

    39 for NAND flash devices presents a single drive Z: to the File Server that

    40 layers thinly over both the core ROM and the ROFS file systems. It redirects

    41 File Server requests to the core ROM or ROFS as required. See <xref href="GUID-775B5858-4358-5195-B580-7C16AE4981C3.dita">Flash

    42 Translation Layer Technology</xref> for more information on why this is required. </p> <p>This

    43 unifies the file systems for flash devices (ROM, ROFS and FAT file systems)

    44 into a common file system that is used with drive <filepath>Z:</filepath>.

    45 The file server will direct requests to the required file system as required. </p> </li>

    46 <li id="GUID-82C41045-11E9-5FC9-AE1E-7626CE45EA61"><p><xref href="GUID-CDB35952-5EE3-5643-BA0A-341FE0FF1A02.dita">FAT

    47 File System</xref> (<filepath>efat.fsy</filepath> or <filepath>elocal.fsy</filepath> when

    48 built for an emulator target.) : The FAT File System implements a file system

    49 that supports the VFAT standard. This is used for user data storage on NAND

    50 Flash, internal RAM drives, and removable media. </p> <p>This is the file

    51 system that was originally used by IBM PCs and is an industry standard for

    52 file systems. It is supported by all operating systems that execute on PCs.

    53 Symbian platform FAT only supports FAT12 and FAT16 types. </p> </li>

    54 <li id="GUID-35A95C58-10C0-5503-A898-CB11AF121A77"><p><xref href="GUID-0988F387-5F26-512E-BDA4-D5800EEC2A77.dita">FAT32

    55 File System</xref> (<filepath>efat32.fsy</filepath>): The FAT32 File System

    56 implements the enhanced version of the FAT file system standard that includes

    57 FAT32 support. </p> <p>The FAT32 file system is an update of the industry

    58 standard FAT file system. The Symbian platform FAT32 file system supports

    59 the FAT12, FAT16 and FAT32 file systems. </p> </li>

    60 <li id="GUID-E48530A9-A7BE-5EB1-B2F4-70779963B898"><p><xref href="GUID-15DD2080-83D6-5DE0-8B75-D4A5934C8C91.dita">ISO9660

    61 File System</xref> (<filepath>iso9660.fsy</filepath>): The ISO9660 File System

    62 implements a ISO9660 file system, that reads CDROM and DVD-ROM. This is only

    63 for the internal X86 port. </p> <p>The ISO9660 is an internationally agreed

    64 standard for the file system used by CD-ROM and DVD-ROM media. </p> <p> <note> ISO9660

    65 is for Symbian internal use only. </note> </p> </li>

    66 <li id="GUID-19C89E46-95EC-5F0D-AF66-ADB94A2ED408"><p><xref href="GUID-6FD18A95-2530-565C-8C92-E893649F2E59.dita">LFFS

    67 File System</xref> (<filepath>elffs.fsy</filepath>): The LFFS File System

    68 provides data storage on NOR type flash memory, and is portable to a wide

    69 range of Flash devices. </p> <p>LFFS is designed specifically to be used with

    70 NOR flash and has the ability to protect itself against power loss. </p> </li>

    71 <li id="GUID-9A1088B0-2928-5F1E-A73A-FE40254BB987"><p><xref href="GUID-57C0B4C9-255A-50CD-8E99-DD1A754060C0.dita">NTFS

    72 File System</xref> (<filepath>ntfs.fsy</filepath>): The NTFS File System provides

    73 read-only support for the NTFS file system standards. This is only for the

    74 internal X86 port. </p> <p>This is the file system for Windows NT, Windows

    75 2000, Windows-XP, Windows Server 2003, Windows Server 2008 and Windows Vista. </p> <p> <note> NTFS

    76 is for Symbian internal use only. </note> </p> </li>

    77 <li id="GUID-776918FD-4408-50D6-BEB2-9B1D991C1E97"><p><xref href="GUID-466628A1-80BB-57E7-8315-CD9E0A95CDC3.dita">ROFS

    78 File System</xref> (<filepath>erofs.fsy</filepath>): The Read-only File System

    79 (ROFS) supports a ROM-structured local file system that can be located on

    80 NAND flash, or other media, where executables are not executed in place (non-XIP). </p> <p>ROFS

    81 stands for Read Only File System and is used for accessing code storage on

    82 media that cannot be executed in that media (otherwise known as non-XIP storage),

    83 for example NAND flash. </p> </li>

    84 <li id="GUID-2E0072DF-6234-5D61-BB44-0F6DE6D062CF"><p><xref href="GUID-EB6CA066-B567-5542-9D41-183B27A70B82.dita">ROM

    85 File System</xref> (No FSY, ROM is the default file system build defined by <filepath>f32.iby</filepath>):

    86 The ROM file system is used to access the "core ROM image": this contains

    87 files that are copied from NAND Flash storage into RAM on boot. </p> <p>This

    88 is the file system that is used when the phone boots up. </p> </li>

    89 <li id="GUID-FC28E385-C8D1-5E90-B075-B8FA09FA09F5"><p><xref href="GUID-61BAA598-4D13-5859-8751-DA949744E27F.dita">USB

    90 Mass Storage File System</xref> (<filepath>msfs.fsy</filepath> and possibly <filepath>msfs_db.fsy</filepath>,

    91 depending on configuration): The USB Mass Storage File System is provided

    92 to support a licensee-provided USB mass storage application, which allows

    93 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

    94 used when a USB memory device is connected directly to the device executing

    95 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

    96 Mass Storage File System</xref> is used when the media on the device is accessed

    97 by an external device i.e. a PC when it is in "USB mass storage" mode. </p> </li>

    98 </ul> </section>

    99 <section id="GUID-2C14C280-9442-462A-BE5A-8C49A96FB8E4"><title>Using File

   100 System Plug-ins</title> <p>The file systems are used to allow kernel access

   101 to data on a media storage device such as Flash, MMC cards, SD cards, etc.

   102 A file systems FSY plug-in must be added to the file server and mounted before

   103 the kernel is granted access. </p> <p>Accessing a file system specific device

   104 requires: </p> <ul>

   105 <li id="GUID-5E8C4326-5A6F-51D7-9C84-8AF5F6BC36AF"><p>Adding a file system

   106 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>

   107 <li id="GUID-DBC20D4D-D358-5668-B9D8-BDF68A441A7E"><p>Mounting the file system

   108 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>

   109 </ul> <p>The file server handles all requests to access a mounted file system. </p> </section>

   110 </conbody><related-links>

   111 <link href="GUID-9E92EE30-F2E2-5F28-BB2A-391C09EC69D2.dita"><linktext>Using ECom</linktext>

   112 </link>

   113 <link href="GUID-F3BD37EC-0CCB-5859-908F-215E22C9FC20.dita#GUID-F3BD37EC-0CCB-5859-908F-215E22C9FC20/GUID-143780ED-4A23-5E72-A923-F605172EC8B5">

   114 <linktext>File Server</linktext></link>

   115 </related-links></concept>