Flash memory architecture with separate storage of overhead and user data
View Patent ↗A flash memory system segregates overhead data from user data so that overhead data may be addressed, programmed and erased independently from user data. The non-volatile memory medium of a flash memory system is mapped into a plurality of separate and separately addressable memory blocks that are independently programmable and independently erasable, including Dedicated Overhead Blocks and Dedicated Data Blocks. The Dedicated Overhead Blocks are mapped according to a plurality of distinguishably addressable segments. User Data defined by a VLBA is stored in a Dedicated Data Block within the flash memory. Successively generated sets of Overhead Data are stored in respective segments in the Dedicated Overhead Blocks. When a Dedicated Overhead Block is designated for erasure, any current overhead segments are consolidated and moved to a new Dedicated Overhead Block., and the full or obsolete block is erased.
1. A method of data storage within a Flash Memory System comprising the steps:
a. mapping a non-volatile memory medium within the Flash Memory System into a plurality of independently addressable, independently programmable and independently erasable memory blocks including a plurality of Dedicated Data Blocks and a plurality of Dedicated Overhead Blocks comprising a first Dedicated Overhead Block and a second Dedicated Overhead Block;
b. mapping each of the plurality of Dedicated Overhead Blocks into a plurality of consecutively addressed Overhead Segments, wherein the plurality of segments within each Dedicated Overhead Block are addressed according to an identical set of distinct segment addresses, each segment comprising a Physical Address Register and a Flag Field; and
c. correlating the first Dedicated Overhead Block to a first group of Virtual Logical Block Addresses including a first Virtual Logical Block Address,
wherein user data and overhead data are segregated in separate memory blocks, such that the user data are stored only in the plurality of dedicated data blocks and the overhead data are separately stored only in the plurality of dedicated overhead blocks and the erasure of one the plurality of memory blocks only erases data selected from either a Dedicated Data Block or a Dedicated Overhead Block.
2. The method according to claim 1 wherein each Overhead Segment further comprises an Error Correction Field for storing error correction data supporting the User Data.
3. The method according to claim 1 wherein the step of correlating is performed through a RAM space manager.
4. The method according to claim 3 further comprising the steps:
a. storing a logical address within a non-volatile correlation register within the Flash Memory System; and
b. loading a physical address into a correlation register of the RAM space manager upon power up.
5. The method according to claim 1 further comprising the steps:
a. marking as defective a dedicated overhead block; and
b. re-designating a dedicated data block as a dedicated overhead block.
6. A flash memory device for storing User Data comprising a plurality of separate, independently addressable, independently programmable and independently erasable non-volatile Physical Memory Blocks distinguishably defined by a plurality of Physical Block Addresses including:
a. a plurality of dedicated data Blocks for storing User Data only; and
b. a plurality of consecutively addressed Dedicated Overhead Blocks for only storing Overhead Data including a first Dedicated Overhead Block and a second Dedicated Overhead Block,
wherein the plurality of dedicated data blocks is segregated from the plurality of dedicated overhead blocks and the erasure of one the plurality of Physical Memory Blocks only erases data selected from either a Dedicated Data Block or a Dedicated Overhead Block.
7. The Flash Memory device according to claim 6 wherein each Dedicated Overhead Block is identically comprised of a plurality of separately addressable Overhead Pages, each block following an identical sequence of page addresses.
8. The Flash Memory Device according to claim 7 wherein each Overhead Page is comprised of a plurality of independently addressable and independently programmable segments, including a plurality of Overhead Segments.
9. The Flash Memory Device according to claim 8 wherein the plurality of independent Overhead Segments are used for storing Overhead Data, each Overhead Segment supporting one Virtual Logical Block of User Data, each Overhead Segment comprising:
a. physical Address Register for storing a Physical Address for locating corresponding User Data; and
b. a flag field.
10. The Flash Memory Device according to claim 9 wherein a first group of Virtual Logical Block Addresses including a first VLBA are assigned to the first Dedicated Overhead Block, such that overhead data generated in support of the first VLBA will be stored in an Overhead Segment within the first Dedicated Overhead Block.
11. The Flash Memory device according to claim 6 further comprising a controller for regulating and controlling an operation of the Flash memory device.
12. The Flash memory device according to claim 6 further comprising a volatile RAM Space Manager, the Space Manager comprising a plurality of correlation fields for correlating virtual addresses and physical addresses.
13. The Flash Memory device according to claim 12 wherein the Space Manager comprises a Flag Register comprising a plurality of Status Flags.
14. The Flash Memory device according to claim 13 further comprising a means for loading data from a non-volatile memory area into the Space Manager on start up.
15. The Flash Memory device according to claim 13 further comprising a means for loading data into the Space Manager upon a reset command.
16. The Flash Memory device according to claim 6 further comprising means for generating error correction data corresponding to User Data stored within the Flash Memory device.
17. The Flash Memory device according to claim 6 comprising a means for re-designating a Dedicated Data Block to function as a Dedicated Overhead Block in the event of failure of an existing Dedicated Overhead Block.