Direct file data programming and deletion in flash memories

• US 20060184723A1
• Filed: 01/26/2006
• Published: 08/17/2006
• Est. Priority Date: 02/16/2005
• Status: Abandoned Application

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Sinclair, Alan W., Smith, Peter J.
• Application Number:
  US11/342,170
• Publication Number:
  US 20060184723A1
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 16/16 for erasing blocks, e.g. arrays, words, groups

Abstract

Host system data files are written directly to a large erase block flash memory system with a unique identification of each file and offsets of data within the file but without the use of any intermediate logical addresses or a virtual address space for the memory. Directory information of where the files are stored in the memory is maintained within the memory system by its controller, rather than by the host. The file based interface between the host and memory systems allows the memory system controller to utilize the data storage blocks within the memory with increased efficiency.

Claims

1. A memory system, comprising:

an array of non-volatile charge storing semiconductor memory cells organized into a plurality of individual blocks of memory cells that are simultaneously erased prior to new data being written therein, and

a controller connected with the memory cell array that operates to (a) cause data received by the memory system with offset addresses within a uniquely identified file to be stored in a selected one or more of the blocks of the memory array, (b) keep track of the blocks in which data of the uniquely identified files are stored by their offset addresses, and (c) in response to receiving a command to delete a specific file, cause data of the specific file stored in the selected one or more blocks to be deleted.

2. The memory system of claim 1, wherein the controller further operates (c) in response to the received delete command to first cause the data stored in any of the one or more blocks containing received data of only the specific file to be marked obsolete and subsequently cause the one or more blocks with all their received data marked obsolete to be erased.

3. The memory system of claim 2, wherein the controller further operates in response to the received delete command to (c) cause received data of the specific file in any common of the selected one or more blocks that also contain valid data of another file to be marked obsolete, subsequently causing the valid data of the common block to be consolidated with other valid data in another block, and then causing the common block to be erased.

4. The memory system of claim 1, wherein the controller further operates to cause data of the specific file stored in the selected one or more blocks to be deleted by first listing the selected one or more blocks in a consolidation queue that also lists other blocks as a result of operations not involving receipt a command to delete a file, and then later deleting the data of the selected one or more blocks in order of their position within the queue.