FatFs: Update to release R0.12c.

firmware/chibios-portapack/ext/fatfs/doc/en/appnote.html

@@ -64,7 +64,7 @@ The FatFs module assumes that size of <tt>char</tt>/<tt>short</tt>/<tt>long</tt>
 <div class="para doc" id="limits">
 <h3>Limits</h3>
 <ul>
-<li>File system type: FAT12, FAT16, FAT32(r0.0) and exFAT(r1.0).</li>
+<li>File system type: FAT, FAT32(r0.0) and exFAT(r1.0).</li>
 <li>Number of open files: Unlimited. (depends on available memory)</li>
 <li>Number of volumes: Upto 10.</li>
 <li>Volume size: Upto 2 TiB at 512 bytes/sector.</li>
@@ -144,7 +144,7 @@ And other options are left unchanged from original setting.
 
 <div class="para doc" id="lfn">
 <h3>Long File Name</h3>
-<p>FatFs module supports long file name (LFN). The two different file names, short file name (SFN) and LFN, of a file is transparent on the API except for <tt>f_readdir</tt> function. The support for LFN is disabled by default. To enable the LFN, set <tt><a href="config.html#use_lfn">_USE_LFN</a></tt> to 1, 2 or 3, and add <tt>option/unicode.c</tt> to the project. The LFN requiers a certain working buffer in addition. The buffer size can be configured by <tt><a href="config.html#max_lfn">_MAX_LFN</a></tt> according to the available memory. The length of an LFN will be up to 255 characters, so that the <tt>_MAX_LFN</tt> should be set to 255 for all file names. If the size of working buffer is insufficient for the input file name, the file function fails with <tt>FR_INVALID_NAME</tt>. When use any re-entry to the API with LFN is enabled, <tt>_USE_LFN</tt> must be set to 2 or 3. In this case, the file function allocates the working buffer on the stack or heap. The working buffer occupies <tt>(_MAX_LFN + 1) * 2</tt> bytes and additional 608 bytes when exFAT enabled.</p>
+<p>FatFs module supports long file name (LFN). The two different file names, short file name (SFN) and LFN, of a file is transparent on the API except for <tt>f_readdir</tt> function. The support for LFN is disabled by default. To enable the LFN, set <tt><a href="config.html#use_lfn">_USE_LFN</a></tt> to 1, 2 or 3, and add <tt>option/unicode.c</tt> to the project. The LFN requiers a certain working buffer in addition. The buffer size can be configured by <tt><a href="config.html#max_lfn">_MAX_LFN</a></tt> according to the available memory. The length of an LFN will be up to 255 characters, so that the <tt>_MAX_LFN</tt> should be set to 255 for all file names. If the size of working buffer is insufficient for the input file name, the file function fails with <tt>FR_INVALID_NAME</tt>. When use any re-entry to the API with LFN is enabled, <tt>_USE_LFN</tt> must be set to 2 or 3. In this case, the file function allocates the working buffer on the stack or heap. The working buffer occupies <tt>(_MAX_LFN + 1) * 2</tt> bytes and additional <tt>(_MAX_LFN + 44) / 15 * 32</tt> bytes when exFAT is enabled.</p>
 <table class="lst2 rset">
 <caption>With LFN at CM3+gcc</caption>
 <tr><th><tt>_CODE_PAGE</tt></th><th>Code size</th></tr>
@@ -165,22 +165,22 @@ And other options are left unchanged from original setting.
 
 <div class="para doc" id="exfat">
 <h3>exFAT File System</h3>
-<p>The exFAT (Microsoft's Extended File Allocation Table) file system is a replacement of the FAT file system which has been widely used in the embedded systems and consumer devices. It is adopted by SDA (SD Association) as a recommended file system for high capacity SD cards (&gt;32GB) and they are being shipped with this format, so that the exFAT will soon become one of the standard file systems for removable media.</p>
-<p>The exFAT file system allows the file size larger than 4 GiB limit what FAT file system allows upto and some file system overhead, especially file allocation delay, are reduced as well. This feature improves the write throughput to the file. However a problem on the current implementation of FatFs is that write throughput at writing to the growing edge of the fragmented file gets less than the throughput on the FAT volume. Pre-allocating a contiguous block with <tt>f_expand</tt> function may be a workaround of this problem.</p>
-<p>Note that the exFAT is a patent of Microsoft Corporation. The exFAT function of FatFs is an implementation based on US. Pat. App. Pub. No. 2009/0164440 A1. FatFs module can swich the exFAT on/off by configuration option. When enable the exFAT on the commercial products, you will need to be licensed by Microsoft depends on the final destination of the products.</p></div>
-<p><em>Remark: Enabling exFAT discards C89 compatibility because of need for 64-bit integer type.</em></p>
+<p>The exFAT (Microsoft's Extended File Allocation Table) file system is a replacement of the FAT file system which has been widely used in the embedded systems and consumer devices. It is adopted by SDA (SD Association) as a recommended file system for high capacity SD cards (&gt;32GB) and they are being shipped with this format, so that the exFAT become one of the standard file systems for removable media as well as FAT. The exFAT file system allows the file size larger than 4 GiB limit what FAT file system allows upto and some file system overhead, especially cluster allocation delay, are reduced as well. This feature improves the write throughput to the file.</p>
+<p>Note that the exFAT is a patent of Microsoft Corporation. The exFAT function of FatFs is an implementation based on <cite>US. Pat. App. Pub. No. 2009/0164440 A1</cite>. FatFs module can swich the exFAT on/off by configuration option. When enable the exFAT on the commercial products, you will need to be licensed by Microsoft depends on the final destination of the products.</p>
+<p><em>Remark: Enabling exFAT discards ANSI C (C89) compatibility because of need for 64-bit integer type.</em></p>
+</div>
 
 <div class="para doc" id="reentrant">
 <h3>Re-entrancy</h3>
-<p>The file operations to the different volume is always re-entrant regardless of configurations except when LFN enabled with static working buffer. It can work simultaneously without any mutual exclusion.</p>
-<p>The file operations to the same volume is not re-entrant but it can also be configured thread-safe by option <tt><a href="config.html#fs_reentrant">_FS_REENTRANT</a></tt>. It enables to control exclusive use of each file system object. In this case, also the OS dependent synchronization object control functions, <tt>ff_cre_syncobj/ff_del_syncobj/ff_req_grant/ff_rel_grant</tt>, needed to be added to the project. There are some examples in the <tt>option/syscall.c</tt>.</p>
+<p>The file operations to the <em>different volume</em> each other is always re-entrant regardless of configurations except when LFN enabled with static working buffer. It can work simultaneously without any mutual exclusion.</p>
+<p>The file operations to the <em>same volume</em> is not re-entrant. It can also be configured thread-safe by option <tt><a href="config.html#fs_reentrant">_FS_REENTRANT</a></tt>. It enables to control exclusive use of each file system object. In this case, also the OS dependent synchronization object control functions, <tt>ff_cre_syncobj/ff_del_syncobj/ff_req_grant/ff_rel_grant</tt>, needed to be added to the project. There are some examples in the <tt>option/syscall.c</tt>.</p>
 <p>When a file function is called while the volume is being accessed by other task, the file function to the volume will be suspended until that task leaves the file function. If the wait time exceeded a period defined by <tt>_TIMEOUT</tt>, the file function will abort with <tt>FR_TIMEOUT</tt>. The timeout function might not be supported on the some RTOSs.</p>
-<p>There is an exception on the re-entrancy for <tt>f_mount/f_mkfs/f_fdisk</tt> function. These volume management functions are not re-entrant to the same volume and corresponding physical drive. When use these functions, other tasks need to avoid to access the volume.</p>
-<p>Note that this section describes on the re-entrancy of the FatFs module itself. The <tt>_FS_REENTRANT</tt> controls only exclusive use of each file system object and it does not that prevent to re-enter the low level disk functions. For example, only <tt>disk_status</tt> function can be re-entered at single volume system and any disk function can be re-entered at multiple volume system. Thus the low level disk I/O layer must be always thread-safe when any FatFs API is re-entered by two or more tasks.</p>
+<p>There is an exception on the re-entrancy for <tt>f_mount/f_mkfs/f_fdisk</tt> function. These volume management functions are not re-entrant on the same volume and corresponding physical drive. When use these functions, other tasks need to avoid to access the volume.</p>
+<p>Note that this section describes on the re-entrancy of the FatFs module itself. The <tt>_FS_REENTRANT</tt> controls only exclusive use of each file system object and it does not that prevent re-entering the low level disk functions. For example, only <tt>disk_status</tt> function is re-entered at single volume system and every disk function is re-entered at multiple volume system. Thus the low level disk I/O layer must be always thread-safe when FatFs API is re-entered by two or more tasks.</p>
 </div>
 
 <div class="para doc" id="dup">
-<h3>Duplicated File Access</h3>
+<h3>Duplicated File Open</h3>
 <p>FatFs module does not support the read/write collision control of duplicated open to a file. The duplicated open is permitted only when each of open method to a file is read mode. The duplicated open with one or more write mode to a file is always prohibited, and also open file must not be renamed or deleted. A violation of these rules can cause data colluption.</p>
 <p>The file lock control can be enabled by <tt><a href="config.html#fs_lock">_FS_LOCK</a></tt> option. The value of option defines the number of open objects to manage simultaneously. In this case, if any open, rename or remove that violating the file shareing rule that described above is attempted, the file function will rejected with <tt>FR_LOCKED</tt>. If number of open objects, files and sub-directories, is equal to <tt>_FS_LOCK</tt>, an extra <tt>f_open/f_opendir</tt> function will fail with <tt>FR_TOO_MANY_OPEN_FILES</tt>.</p>
 </div>
@@ -274,7 +274,7 @@ Figure 5. Minimized critical section<br>
 / by use of this software.
 /----------------------------------------------------------------------------*/
 </pre>
-<p>Therefore FatFs license is one of the BSD-style licenses but there is a significant feature. FatFs is mainly intended for embedded systems. In order to extend the usability for commercial products, the redistributions of FatFs in binary form, such as embedded code, binary library and any forms without source code, does not need to include about FatFs in the documentations. This is equivalent to the 1-clause BSD license. Of course FatFs is compatible with the most open source software licenses including GNU GPL. When you redistribute the FatFs source code with any changes or create a fork, the license can also be changed to GNU GPL, BSD-style license or any open source software licenses that not conflict with FatFs license.</p>
+<p>Therefore FatFs license is one of the BSD-style licenses but there is a significant feature. FatFs is mainly intended for embedded systems. In order to extend the usability for commercial products, the redistributions of FatFs in binary form, such as embedded code, binary library and any forms without source code, does not need to include about FatFs in the documentations. This is equivalent to the 1-clause BSD license. Of course FatFs is compatible with the most of open source software licenses including GNU GPL. When you redistribute the FatFs source code with any changes or create a fork, the license can also be changed to GNU GPL, BSD-style license or any open source software license that not conflict with FatFs license.</p>
 </div>
 
 <p class="foot"><a href="../00index_e.html">Return Home</a></p>

firmware/chibios-portapack/ext/fatfs/doc/en/dread.html

@@ -60,8 +60,8 @@ DRESULT disk_read (
 <p>The memory address specified by <tt class="arg">buff</tt> is not that always aligned to word boundary because the argument is defined as <tt>BYTE*</tt>. The unaligned read/write request can occure at <a href="appnote.html#fs1">direct transfer</a>. If the bus architecture, especially DMA controller, does not allow unaligned memory access, it should be solved in this function. There are some workarounds described below to avoid this issue.</p>
 <ul>
 <li>Convert word transfer to byte transfer in this function if needed. - Recommended.</li>
-<li>On the <tt>f_read</tt> calls, avoid long read request that includes a whole of sector. - Any direct transfer never occures.</li>
-<li>On the <tt>f_read</tt> calls, make sure that <tt>(((UINT)data &amp; 3) == (f_tell(fp) &amp; 3))</tt> is true. - Word alignment of <tt class="arg">buff</tt> is guaranteed.</li>
+<li>On the <tt>f_read()</tt> calls, avoid long read request that includes a whole of sector. - Any direct transfer never occures.</li>
+<li>On the <tt>f_read(fp, data, btw, bw)</tt> calls, make sure that <tt>(((UINT)data &amp; 3) == (f_tell(fp) &amp; 3))</tt> is true. - Word alignment of <tt class="arg">buff</tt> is guaranteed.</li>
 </ul>
 <p>Generally, a multiple sector transfer request must not be split into single sector transactions to the storage device, or you will not get good read throughput.</p>
 </div>

firmware/chibios-portapack/ext/fatfs/doc/en/dstat.html

@@ -35,7 +35,7 @@ DSTATUS disk_status (
 <p>The current drive status is returned in combination of status flags described below. FatFs refers only <tt>STA_NOINIT</tt> and <tt>STA_PROTECT</tt>.</p>
 <dl class="ret">
 <dt>STA_NOINIT</dt>
-<dd>Indicates that the device is not initialized and not ready to work. This flag is set on system reset, media removal or failure of <tt>disk_initialize</tt> function. It is cleared on <tt>disk_initialize</tt> function succeeded. Any media change that occurs asynchronously must be captured and reflect it to the status flags, or auto-mount function will not work correctly. If the system does not support media change detection, application program needs to force de-initialize the file system object and re-mount the volume with <tt>f_mount</tt> function after each media change.</dd>
+<dd>Indicates that the device is not initialized and not ready to work. This flag is set on system reset, media removal or failure of <tt>disk_initialize</tt> function. It is cleared on <tt>disk_initialize</tt> function succeeded. Any media change that occurs asynchronously must be captured and reflect it to the status flags, or auto-mount function will not work correctly. If the system does not support media change detection, application program needs to explicitly re-mount the volume with <tt>f_mount</tt> function after each media change.</dd>
 <dt>STA_NODISK</dt>
 <dd>Indicates that no medium in the drive. This is always cleared at fixed disk drive. Note that FatFs does not refer this flag.</dd>
 <dt>STA_PROTECT</dt>

firmware/chibios-portapack/ext/fatfs/doc/en/dwrite.html

@@ -60,7 +60,7 @@ DRESULT disk_write (
 <h4>Description</h4>
 <p>The specified memory address is not that always aligned to word boundary because the type of pointer is defined as <tt>BYTE*</tt>. For more information, refer to the description of <a href="dread.html"><tt>disk_read</tt></a> function.</p>
 <p>Generally, a multiple sector transfer request must not be split into single sector transactions to the storage device, or you will never get good write throughput.</p>
-<p>FatFs expects delayed write function of the disk control layer. The write operation to the media does not need to be completed when return from this function by what write operation is in progress or data is only stored into the write-back cache. But write data on the <tt class="arg">buff</tt> is invalid after return from this function. The write completion request is done by <tt>CTRL_SYNC</tt> command of <tt><a href="dioctl.html">disk_ioctl</a></tt> function. Therefore, if a delayed write function is implemented, the write throughput will be improved.</p>
+<p>FatFs expects delayed write function of the disk control layer. The write operation to the media does not need to be completed when return from this function by what write operation is in progress or data is only stored into the write-back cache. But write data on the <tt class="arg">buff</tt> is invalid after return from this function. The write completion request is done by <tt>CTRL_SYNC</tt> command of <tt><a href="dioctl.html">disk_ioctl</a></tt> function. Therefore, if a delayed write function is implemented, the write throughput of the file system will be improved.</p>
 <p><em>Remarks: Application program MUST NOT call this function, or FAT structure on the volume can be collapsed.</em></p>
 </div>
 

firmware/chibios-portapack/ext/fatfs/doc/en/expand.html

@@ -60,8 +60,8 @@ FRESULT f_expand (
 <li>Not allowable file size. (&gt;= 4GiB on FAT volume)</li>
 </ul>
 <p>When <tt class="arg">opt</tt> is 0, the function finds a contiguous data area and set it as suggested point for next allocation instead of allocating it to the file. The next cluster allocation is started at top of the contiguous area found by this function. Thus the write file is guaranteed be contiguous and no allocation delay until the size reaches that size at least unless any other changes to the volume is performed.</p>
-<p>The contiguous file would have an advantage at time-critical read/write operations. It reduces some overheads in the file system and the storage media caused by random access due to fragmented file data. Especially FAT access for the contiguous file on the exFAT volume is completely eliminated and storage media will be accessed sequentially.</p>
-<p>Also the contiguous file data can be easily accessed directly via low-level disk functions. But this is not recommended in consideration for future compatibility.</p>
+<p>The contiguous file would have an advantage at time-critical read/write operations. It eliminates some overheads in the file system and the storage media caused by random access due to fragmented file data. Especially FAT access for the contiguous file on the exFAT volume is completely eliminated and storage media will be accessed sequentially.</p>
+<p>Also the contiguous file can be easily accessed directly via low-level disk functions. But this is not recommended in consideration for future compatibility.</p>
 </div>
 
 <div class="para comp">
@@ -79,28 +79,29 @@ FRESULT f_expand (
     res = f_open(fp = malloc(sizeof (FIL)), "file.dat", FA_WRITE|FA_CREATE_ALWAYS);
     if (res) { <span class="c">/* Check if the file has been opened */</span>
         free(fp);
-        ...
+        die("Failed to open the file.");
     }
 
     <span class="c">/* Alloacte a 100 MiB of contiguous area to the file */</span>
     res = f_expand(fp, 104857600, 1);
     if (res) { <span class="c">/* Check if the file has been expanded */</span>
-        ...
+        f_close(fp);
         free(fp);
-        ...
+        die("Failed to allocate contiguous area.");
     }
+
     <span class="c">/* Now you have a contiguous file accessible with fp */</span>
 
 </pre>
 <pre>
-    <span class="c">/* Accessing the file data directly via low-level disk functions */</span>
+    <span class="c">/* Accessing the contiguous file via low-level disk functions */</span>
 
     <span class="c">/* Get physical location of the file data */</span>
     drv = fp-&gt;obj.fs-&gt;drv;
-    sect = fp-&gt;obj.fs-&gt;database + fp-&gt;obj.fs-&gt;csize * (fp-&gt;obj.sclust - 2);
+    lba = fp-&gt;obj.fs-&gt;database + fp-&gt;obj.fs-&gt;csize * (fp-&gt;obj.sclust - 2);
 
     <span class="c">/* Write 2048 sectors from top of the file at a time */</span>
-    res = disk_write(drv, buffer, sect, 2048);
+    res = disk_write(drv, buffer, lba, 2048);
 
 </pre>
 </div>

firmware/chibios-portapack/ext/fatfs/doc/en/fdisk.html

@@ -62,15 +62,14 @@ FRESULT f_fdisk (
     <span class="c">/* Volume management table defined by user (required when _MULTI_PARTITION == 1) */</span>
 
     PARTITION VolToPart[] = {
-        {0, 1},    <span class="c">/* Logical drive 0 ==> Physical drive 0, 1st partition */</span>
-        {0, 2},    <span class="c">/* Logical drive 1 ==> Physical drive 0, 2nd partition */</span>
-        {1, 0}     <span class="c">/* Logical drive 2 ==> Physical drive 1, auto detection */</span>
+        {0, 1},    <span class="c">/* "0:" ==> Physical drive 0, 1st partition */</span>
+        {0, 2},    <span class="c">/* "1:" ==> Physical drive 0, 2nd partition */</span>
+        {1, 0}     <span class="c">/* "2:" ==> Physical drive 1, auto detection */</span>
     };
 </pre>
 <pre>
     <span class="c">/* Initialize a brand-new disk drive mapped to physical drive 0 */</span>
 
-    FATFS fs;
     DWORD plist[] = {50, 50, 0, 0};  <span class="c">/* Divide drive into two partitions */</span>
     BYTE work[_MAX_SS];
 

firmware/chibios-portapack/ext/fatfs/doc/en/lseek.html

@@ -29,7 +29,7 @@ FRESULT f_lseek (
 <dt>fp</dt>
 <dd>Pointer to the open file object.</dd>
 <dt>ofs</dt>
-<dd>Byte offset from top of the file. The data type <tt>FSIZE_t</tt> is an alias of either <tt>DWORD</tt>(32-bit) or <tt>QWORD</tt>(64-bit) depends on the configuration option <tt>_FS_EXFAT</tt>.</dd>
+<dd>Byte offset from top of the file to set read/write pointer. The data type <tt>FSIZE_t</tt> is an alias of either <tt>DWORD</tt>(32-bit) or <tt>QWORD</tt>(64-bit) depends on the configuration option <tt>_FS_EXFAT</tt>.</dd>
 </dl>
 </div>
 
@@ -48,7 +48,8 @@ FRESULT f_lseek (
 
 <div class="para desc">
 <h4>Description</h4>
-<p>The <tt>f_lseek</tt> function moves the file read/write pointer of an open file. The offset can be specified in only origin from top of the file. When an offset beyond the file size is specified at write mode, the file size is expanded to the specified offset. The file data in the expanded area is <em>undefined</em> because no data is written to the file in this process. This is suitable to pre-allocate a cluster chain quickly, for fast write operation. When a contiguous data area needs to be allocated to the file, use <tt>f_expand</tt> function instead. After the <tt>f_lseek</tt> function succeeded, the current read/write pointer should be checked in order to make sure the read/write pointer has been moved correctry. In case of the read/write pointer is not the expected value, either of followings has been occured.</p>
+<p>File read/write ponter in the open file object points the data byte to be read/written at next read/write operation. It advances as the number of bytes read/written. The <tt>f_lseek</tt> function moves the file read/write pointer without any read/write operation to the file.</p>
+<p>When an offset beyond the file size is specified at write mode, the file size is expanded to the specified offset. The file data in the expanded area is <em>undefined</em> because no data is written to the file in this process. This is suitable to pre-allocate a data area to the file quickly for fast write operation. When a contiguous data area needs to be allocated to the file, use <tt>f_expand</tt> function instead. After the <tt>f_lseek</tt> function succeeded, the current read/write pointer should be checked in order to make sure the read/write pointer has been moved correctry. In case of the read/write pointer is not the expected value, either of followings has been occured.</p>
 <ul>
 <li>End of file. The specified <tt class="arg">ofs</tt> was clipped at end of the file because the file has been opened in read-only mode.</li>
 <li>Disk full. There is no free space on the volume to expand the file.</li>

firmware/chibios-portapack/ext/fatfs/doc/en/mkfs.html

@@ -29,7 +29,7 @@ FRESULT f_mkfs (
 <h4>Parameters</h4>
 <dl class="par">
 <dt>path</dt>
-<dd>Pointer to the null-terminated string specifies the <a href="filename.html">logical drive</a> to be formatted. If there is no drive number in it, it means the default drive. The logical drive may or may not be mounted for the format process.</dd>
+<dd>Pointer to the null-terminated string specifies the <a href="filename.html">logical drive</a> to be formatted. If it has no drive number in it, it means the default drive. The logical drive may or may not be mounted for the format process.</dd>
 <dt>opt</dt>
 <dd>Specifies the format option in combination of <tt>FM_FAT</tt>, <tt>FM_FAT32</tt>, <tt>FM_EXFAT</tt> and bitwise-or of these three, <tt>FM_ANY</tt>. <tt>FM_EXFAT</tt> is ignored when exFAT is not enabled. These flags specify which FAT type to be created on the volume. If two or more types are specified, one out of them will be selected depends on the volume size. The flag <tt>FM_SFD</tt> specifies to place the volume on the drive in SFD format.</dd>
 <dt>au</dt>
@@ -37,7 +37,7 @@ FRESULT f_mkfs (
 <dt>work</dt>
 <dd>Pointer to the working buffer used for the format process.</dd>
 <dt>len</dt>
-<dd>Size of the working buffer in unit of byte. It needs to be the sector size at least. Plenty of working buffer reduces number of write transaction to the device and the format process will be finished quickly.</dd>
+<dd>Size of the working buffer in unit of byte. It needs to be the sector size at least. Plenty of working buffer reduces number of write transactions to the drive and the format process will be finished quickly.</dd>
 </dl>
 </div>
 
@@ -57,9 +57,9 @@ FRESULT f_mkfs (
 <div class="para desc">
 <h4>Description</h4>
 <p>The FAT sub-type, FAT12/FAT16/FAT32, of FAT volume except exFAT is determined by only number of clusters on the volume and nothing else, according to the FAT specification issued by Microsoft. Thus which FAT sub-type is selected, is depends on the volume size and the specified cluster size. In case of the combination of FAT type and cluter size specified by argument cannot be valid on the volume, the function will fail with <tt>FR_MKFS_ABORTED</tt>.</p>
-<p>The allocation unit, also called 'cluster', is a unit of disk space allocation for files. When the size of allocation unit is 32768 bytes, a file with 100 bytes in size occupies 32768 bytes of disk space. The space efficiency of disk usage gets worse as increasing size of allocation unit, but, on the other hand, the read/write performance increases as the size of allocation unit. Therefore the allocation unit is a trade-off between space efficiency and performance. For the large storages in GB order, 32768 bytes or larger cluster (this is automatically selected by default) is recommended for most case unless extremely many files are created on a volume.</p>
+<p>The allocation unit, also called 'cluster', is a unit of disk space allocation for files. When the size of allocation unit is 32768 bytes, a file with 100 bytes in size occupies 32768 bytes of disk space. The space efficiency of disk usage gets worse as increasing size of allocation unit, but, on the other hand, the read/write performance increases as the size of allocation unit. Therefore the size of allocation unit is a trade-off between space efficiency and performance. For the large storages in GB order, 32768 bytes or larger cluster (this is automatically selected by default) is recommended for most case unless extremely many small files are created on a volume.</p>
 <p>There are two disk formats, FDISK and SFD. The FDISK format is usually used for harddisk, MMC, SDC, CFC and U Disk. It can divide a physical drive into one or more partitions with a partition table on the MBR (maser boot record, the first sector of the physical drive). The SFD (super-floppy disk) is non-partitioned disk format. The FAT volume starts at the first sector of the physical drive without any disk partitioning. It is usually used for floppy disk, Microdrive, optical disk and most type of super-floppy media. Some systems support only either one of two formats and other is not supported.</p>
-<p>When <tt>FM_SFD</tt> is not specified, a primary partition occupies whole drive space is created and then the FAT volume is created in it. When <tt>FM_SFD</tt> is specified, the FAT volume occupies from the first sector of the drive is created.</p>
+<p>When <tt>FM_SFD</tt> is not specified (the volume is bound to a physical drive), a primary partition occupies whole drive space is created and then the FAT volume is created in it. When <tt>FM_SFD</tt> is specified, the FAT volume occupies from the first sector of the drive is created.</p>
 <p>If the logical drive to be formatted is bound to the specific partition (1-4) by support of multiple partition, <tt><a href="config.html#multi_partition">_MULTI_PARTITION</a></tt>, the FAT volume is created into the partition and <tt>FM_SFD</tt> flag is ignored. The physical drive needs to be partitioned with <tt>f_fdisk</tt> function or any other partitioning tools prior to create the FAT volume with this function.</p>
 </div>
 

firmware/chibios-portapack/ext/fatfs/doc/en/rc.html

@@ -19,7 +19,7 @@
 <dd>The function succeeded.</dd>
 
 <dt id="de">FR_DISK_ERR</dt>
-<dd>An unrecoverable hard error occured in the lower layer, <tt>disk_read</tt>, <tt>disk_write</tt> or <tt>disk_ioctl</tt> function.<br>Note that if once this error occured at any operation to an open file, the file object is aborted and all operations to the file except for close will be rejected.</dd>
+<dd>The lower layer, <tt>disk_read</tt>, <tt>disk_write</tt> or <tt>disk_ioctl</tt> function, reported that an unrecoverable hard error occured.<br>Note that if once this error occured at any operation to an open file, the file object is aborted and all operations to the file except for close will be rejected.</dd>
 
 <dt id="ie">FR_INT_ERR</dt>
 <dd>Assertion failed. An insanity is detected in the internal process. One of the following possibilities is suspected.
@@ -32,7 +32,14 @@ Note that if once this error occured at any operation to an open file, the file
 </dd>
 
 <dt id="nr">FR_NOT_READY</dt>
-<dd>The storage device cannot work due to a failure of <a href="dinit.html"><tt>disk_initialize</tt></a> function due to no medium or any other reason.</dd>
+<dd>The lower layer, <a href="dinit.html"><tt>disk_initialize</tt></a> function, reported that the storage device could not be got ready to work. One of the following possibilities is suspected.
+<ul>
+<li>No medium in the drive.</li>
+<li>Wrong lower layer implementation for the storage device.</li>
+<li>Wrong hardware configuration.</li>
+<li>The storage device is broken.</li>
+</ul>
+</dd>
 
 <dt id="nf">FR_NO_FILE</dt>
 <dd>Could not find the file.</dd>

firmware/chibios-portapack/ext/fatfs/doc/en/readdir.html

@@ -55,7 +55,7 @@ FRESULT f_readdir (
 <li>Setting of <tt>_MAX_LFN</tt> is insufficient for the long file name. (Not the case at <tt>_MAX_LFN == 255</tt>)</li>
 <li>The long file name contains any character not allowed in ANSI/OEM code. (Not the case at <tt>_LFN_UNICODE == 1</tt>)</li>
 </ul>
-<p>There is a problem on reading a directory of exFAT volume. The exFAT does not support short file name. This means no name can be returned on the condition above. If it is the case, a "?" is returned as file name to indicate that the object is not accessible. To avoid this problem, configure FatFs <tt>_LFN_UNICODE = 1</tt> and <tt>_MAX_LFN = 255</tt> to support the full feature of LFN specification.</p>
+<p>There is a problem on reading a directory of exFAT volume. The exFAT does not support short file name. This means no name can be returned on the condition above. If it is the case, "?" is returned into the <tt>fname[]</tt> to indicate that the object is not accessible. To avoid this problem, configure FatFs <tt>_LFN_UNICODE = 1</tt> and <tt>_MAX_LFN = 255</tt> to support the full feature of LFN specification.</p>
 </div>
 
 

firmware/chibios-portapack/ext/fatfs/doc/en/sdir.html

@@ -13,7 +13,7 @@
 
 <div class="para">
 <h2>DIR</h2>
-<p>The <tt>DIR</tt> structure is used for the work area to read a directory by <tt>f_oepndir</tt>, <tt>f_readdir</tt>, <tt>f_findfirst</tt> and <tt>f_findnext</tt> function. Application program must not modify any member in this structure, or any data on the FAT volume can be collapsed.</p>
+<p>The <tt>DIR</tt> structure is used for the work area to read a directory by <tt>f_oepndir</tt>, <tt>f_readdir</tt>, <tt>f_findfirst</tt> and <tt>f_findnext</tt> function. Application program must not modify any member in this structure, or any file on the volume can be collapsed.</p>
 <pre>
 <span class="k">typedef</span> <span class="k">struct</span> {
     _FDID   obj;        <span class="c">/* Owner file sytem object and object identifier */</span>

firmware/chibios-portapack/ext/fatfs/doc/en/sfileinfo.html

@@ -13,7 +13,7 @@
 
 <div class="para">
 <h2>FILINFO</h2>
-<p>The <tt>FILINFO</tt> structure holds information about the object returned by <tt>f_readdir</tt>, <tt>f_findfirst</tt>, <tt>f_findnext</tt> and <tt>f_stat</tt> function.</p>
+<p>The <tt>FILINFO</tt> structure holds information about the object returned by <tt>f_readdir</tt>, <tt>f_findfirst</tt>, <tt>f_findnext</tt> and <tt>f_stat</tt> function. Be careful in the size of structure when LFN is enabled.</p>
 <pre>
 <span class="k">typedef struct</span> {
     FSIZE_t fsize;               <span class="c">/* File size */</span>