diff --git a/Documentation/components/filesystem.rst b/Documentation/components/filesystem.rst
index 5794dc3169..3fce00770d 100644
--- a/Documentation/components/filesystem.rst
+++ b/Documentation/components/filesystem.rst
@@ -41,3 +41,175 @@ pseudo file systems may be mounted in the true, root file system.
 The approach selected by NuttX is intended to support greater
 scalability from the very tiny platform to the moderate platform.
 
+Partition Table
+===============
+
+Text based Partition Table
+----------------------------------
+
+**Summary**
+
+TXTABLE - A text based partition table stored in last eraseblock
+(or in romdisk for backup).
+
+1. The 1st line must be "Magic+Version", current is "TXTABLE0".
+#. The 2nd and remaining lines are partition entries(min: one)
+   in format: "%s %zx %zx"(means name, size and offset (byte)(in hex)).
+#. Size or offset can be default zero(means zero(for 1st entry) or
+   caculate(for others)), and will be caculated by the parser refs to previous
+   and next entries.
+#. The last eraseblock will be registered as pseudo partition named "txtable".
+   If the last eraseblock included by the last real partition, it will be
+   excluded from.
+
+To avoid problems of PTABLE: In case of multiple NuttX binary,
+partition table maybe out of sync.
+
+And it's easier:
+
+1. Text format with simple rules(name + size + offset).
+#. Size or offset can be default(caculated refs to previous
+   and next entries).
+#. Support backup table(eg. /etc/txtable.txt in ROMFS)
+
+Size / Offset can be automatically calculated, case:
+
+1. The offset of the first entry is zero, and the offset of other entries
+   is zero: automatic calculation;
+#. The size of the last entry is zero: fill to the end of the entire Flash
+   (keep the last eraseblock); the size of other entries is zero:
+   automatically calculated(next.offset - current.offset);
+#. Typical case 1: The size of all entries is
+   zero (calculated automatically), and the offset is non-zero;
+#. Typical case 2: The size and offset of a certain entry are all zero,
+   but the size and offset of two adjacent entries are all non-zero;
+
+**Examples**
+
+Both size and offset of "partition6" are zero,
+gap exists between "partition7" and "data",
+and not reserve last eraseblock.
+
+* txtable.txt
+
+  ::
+
+    TXTABLE0
+    partition1 0x6C000 0x4000
+    partition2 0x10000 0x70000
+    partition3 0x80000 0x80000
+    partition4 0x80000 0x100000
+    partition5 0x280000 0x180000
+    partition6 0 0
+    partition7 0x10000 0x480000
+    data 0 0x500000
+
+
+
+* Parsed
+
+  | Reserved last eraseblock, and gap between partition7 and data is kept.
+  | Format: name, offset, size
+
+  ::
+
+    /dev/partition1   offset 0x00004000, size 0x0006c000
+    /dev/partition2   offset 0x00070000, size 0x00010000
+    /dev/partition3   offset 0x00080000, size 0x00080000
+    /dev/partition4   offset 0x00100000, size 0x00080000
+    /dev/partition5   offset 0x00180000, size 0x00280000
+    /dev/partition6   offset 0x00400000, size 0x00080000
+    /dev/partition7   offset 0x00480000, size 0x00010000
+    /dev/data         offset 0x00500000, size 0x00aff000
+    /dev/txtable      offset 0x00fff000, size 0x00001000
+
+More than one not set size or offset
+
+* txtable.txt
+
+  ::
+
+    TXTABLE0
+    partition1 0 0x4000
+    partition2 0 0x70000
+    partition3 0 0x80000
+    partition4 0x80000 0x100000
+    partition5 0x280000 0
+    partition6 0 0
+    partition7 0x10000 0x480000
+    data 0 0x500000
+
+* Parsed
+
+  | Size of partition[2,3,4,6] and data are caculated, and gap between
+    partition7 and data is kept.
+
+  ::
+
+    /dev/partition1   offset 0x00004000, size 0x0006c000
+    /dev/partition2   offset 0x00070000, size 0x00010000
+    /dev/partition3   offset 0x00080000, size 0x00080000
+    /dev/partition4   offset 0x00100000, size 0x00080000
+    /dev/partition5   offset 0x00180000, size 0x00280000
+    /dev/partition6   offset 0x00400000, size 0x00080000
+    /dev/partition7   offset 0x00480000, size 0x00010000
+    /dev/data         offset 0x00500000, size 0x00aff000
+    /dev/txtable      offset 0x00fff000, size 0x00001000
+
+Only one partition entry, and size not spec
+
+* txtable.txt
+
+  ::
+
+    TXTABLE0
+    partition1 0x0 0x4000
+
+* Parsed
+
+  | The last eraseblock was kept, and size is correct.
+
+  ::
+
+    /dev/partition1   offset 0x00004000, size 0x00ffb000
+    /dev/txtable      offset 0x00fff000, size 0x00001000
+
+Blank line && New line delim
+
+* txtable.txt
+
+  | New line: CR + LF / LF.
+  | Additional char/string after "%s %zx %zx".
+
+  ::
+
+    TXTABLE0
+    partition1 0x6C000 0x4000
+    partition2 0 0x70000
+    partition3 0 0x80000
+    partition4 0 0x100000
+    partition5 0x280000 0x180000
+    partition6 0x80000 0x400000   # String between "%s %zx %zx" and "LF" will be ignored.
+    partition7 0x10000 0x480000   # Comments: This is the 7th partition.
+    data 0 0x500000
+    
+    
+    
+    EOF
+
+* Parsed
+
+  | Blank lines are ignored, and new line of both "LF" or "CRLF" are parsed.
+    String between "%s %zx %zx" and "LF" will be ignored(eg. CR, or some comments).
+
+  ::
+
+    /dev/partition1   offset 0x00004000, size 0x0006c000
+    /dev/partition2   offset 0x00070000, size 0x00010000
+    /dev/partition3   offset 0x00080000, size 0x00080000
+    /dev/partition4   offset 0x00100000, size 0x00080000
+    /dev/partition5   offset 0x00180000, size 0x00280000
+    /dev/partition6   offset 0x00400000, size 0x00080000
+    /dev/partition7   offset 0x00480000, size 0x00010000
+    /dev/data         offset 0x00500000, size 0x00aff000
+    /dev/txtable      offset 0x00fff000, size 0x00001000