Storage Devices, Flash Memories, and Methods of Operating Storage Devices

A storage device comprising:

• a flash memory;
• and
• a controller configured to program first bit data and second bit data into the flash memory,
• wherein when programming the second bit data in a current transaction the controller does not back up the first bit data in the current transaction if a sequence number of the first bit data is greater than a reference sequence number and backs up the first bit data in the current transaction if the sequence number of the first bit data is not greater than the reference sequence number;
• wherein the first bit data is less significant bit data than the second bit data;
• and
• wherein the reference sequence number is a sequence number of bit data programmed last in a previous transaction.

A flash memory comprising:

• a first block, first bit data and second bit data being programmed in the first block;
• and
• a second block, wherein the first bit data is not backed up in the second block when the first bit data and the second bit data are programmed in a same transaction and the first bit data is backed up in the second block when the first bit data and the second bit data are programmed in different transactions;
• wherein the first bit data is less significant bit data than the second bit data;
• and
• wherein each of the transactions is determined using a sync signal transmitted from a host.

A method of operating a storage device, the method comprising:

• programming first bit data into a flash memory;
• determining whether a sequence number of the first bit data is greater than a reference sequence number before programming second bit data into the flash memory;
• and
• not backing up the first bit data if the sequence number of the first bit data is greater than the reference sequence number,
• wherein the first bit data is less significant bit data than the second bit data, and the reference sequence number is a sequence number of bit data programmed last in a previous transaction.