Data writing method, memory storage device and memory control circuit unit

A memory storage device comprising:

• a connection interface unit configured to couple to a host system;
• a rewritable non-volatile memory module comprising a plurality of physical erasing units, the physical erasing units being at least grouped into a data area and a spare area;
• and
• a memory control circuit unit coupled to the connection interface unit and the rewritable non-volatile memory module,
• wherein the memory control circuit unit is configured to allocate a plurality of logical units, at least one first logical unit of the logical units is mapped to at least one first physical erasing unit of the physical erasing units in the data area, at least one second logical unit of the logical units is mapped to at least one second physical erasing unit of the physical erasing units in the data area, the at least one first physical erasing unit stores first data and is filled with the first data, and the at least one second physical erasing unit stores second data and is not filled with the second data,
• wherein the memory control circuit unit is further configured to select at least one third physical erasing unit of the physical erasing units from the spare area and determine whether a remaining space in the at least one second physical erasing unit is smaller than a threshold,
• wherein if the remaining space in the at least one second physical erasing unit is not smaller than the threshold, the memory control circuit unit is further configured to issue a first writing command sequence, wherein the first writing command sequence indicates to write the first data into the at least one third physical erasing unit and indicates to write the second data into the at least one second physical erasing unit,
• wherein if the remaining space in the at least one second physical erasing unit is smaller than the threshold, the memory control circuit unit is further configured to select at least one fourth physical erasing unit of the physical erasing units from the spare area and issue a second writing command sequence, wherein the second writing command sequence indicates to write the first data into the at least one third physical erasing unit and indicates to write the second data into the at least one second physical erasing unit and the at least one fourth physical erasing unit.

A memory control circuit unit configured to control a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module comprises a plurality of physical erasing units, the physical erasing units are at least grouped into a data area and a spare area, and the memory control circuit unit comprises:

• a host interface configured to couple to a host system;
• and
• a memory interface configured to couple to the rewritable non-volatile memory module;
• and
• a memory management circuit coupled to the host interface and the memory interface,
• wherein the memory management circuit is configured to allocate a plurality of logical units, at least one first logical unit of the logical units is mapped to at least one first physical erasing unit of the physical erasing units in the data area, at least one second logical unit of the logical units is mapped to at least one second physical erasing unit of the physical erasing units in the data area, the at least one first physical erasing unit stores first data and is filled with the first data, and the at least one second physical erasing unit stores second data and is not filled with the second data,
• wherein the memory management circuit is further configured to select at least one third physical erasing unit of the physical erasing units from the spare area and determine whether a remaining space in the at least one second physical erasing unit is smaller than a threshold,
• wherein if the remaining space in the at least one second physical erasing unit is not smaller than the threshold, the memory management circuit is further configured to issue a first writing command sequence, wherein the first writing command sequence indicates to write the first data into the at least one third physical erasing unit and indicates to write the second data into the at least one second physical erasing unit,
• wherein if the remaining space in the at least one second physical erasing unit is smaller than the threshold, the memory management circuit is further configured to select at least one fourth physical erasing unit of the physical erasing units from the spare area and issue a second writing command sequence, wherein the second writing command sequence indicates to write the first data into the at least one third physical erasing unit and indicates to write the second data into the at least one second physical erasing unit and the at least one fourth physical erasing unit.