Method of storage space management

Abstract

A method of storage space management for a storage device comprising a controller and a memory, comprising: calculating, by the controller, an expectedly used capacity and an effective capacity of the memory, wherein the effective capacity has a negative correlation with a number of blocks marked as bad blocks among a plurality of blocks of the memory; when the effective capacity is less than or equal to the declared capacity, and a difference between the effective capacity and the expectedly used capacity is less than a predetermined threshold capacity, prohibiting, by the controller, programming to the memory; and when the effective capacity is less than or equal to the declared capacity and the difference of the effective capacity and the expectedly used capacity is not less than the predetermined threshold capacity, permitting, by the controller, programming to the memory.

What is claimed is: 
     
         1 . A method of storage space management for a storage device, the storage device comprising a controller and a memory, the storage device having a declared capacity, the method of storage space management comprising:
 calculating, by the controller, an expectedly used capacity and an effective capacity of the memory, wherein the effective capacity has a negative correlation with a number of blocks marked as bad blocks among a plurality of blocks of the memory;   when the effective capacity is less than or equal to the declared capacity, and a difference between the effective capacity and the expectedly used capacity is less than a predetermined threshold capacity, prohibiting, by the controller, programming to the memory; and   when the effective capacity is less than or equal to the declared capacity and the difference of the effective capacity and the expectedly used capacity is not less than the predetermined threshold capacity, permitting, by the controller, programming to the memory.   
     
     
         2 . The method of  claim 1 , wherein the effective capacity minus the predetermined threshold capacity equals a safe capacity. 
     
     
         3 . The method of  claim 2 , wherein the safe capacity is adjustable. 
     
     
         4 . The method of  claim 2 , wherein the safe capacity is proportional to the effective capacity. 
     
     
         5 . The method of  claim 2 , further comprising:
 when the effective capacity is less than or equal to the declared capacity and the difference of the effective capacity and the expectedly used capacity is less than the predetermined threshold capacity, sending a warning signal by the controller.   
     
     
         6 . The method of  claim 5 , further comprising:
 when the effective capacity is less than or equal to the declared capacity and the expectedly used capacity is larger than or equal to the safe capacity, transmitting, by the controller, a warning signal, the expectedly used capacity, and the effective capacity to an electronic device; and   prohibiting, by the electronic device, programming to the memory and displaying a to-be-cleared capacity in response to the warning signal, wherein the to-be-cleared capacity is based on a difference of the expectedly used capacity and the safe capacity.   
     
     
         7 . The method of  claim 1 , wherein the declared capacity is an initial capacity of the storage device after being initialized. 
     
     
         8 . A method of storage space management for a storage device, the storage device comprising a controller and a memory, the storage device having a declared capacity, the method of storage space management comprising:
 calculating, by the controller, an expectedly used capacity and an effective capacity of the memory, wherein the effective capacity has a negative correlation with a number of blocks marked as bad blocks in a plurality of blocks of the memory;   determining, by the controller, whether each of the plurality of blocks of the memory is in a non-use status;   when one of the blocks is determined as in the non-use status, marking the block by the controller as a damaged block or a restricted block, such that the effective capacity is no less than the declared capacity of the storage device; and   comparing, by the controller, a difference of the effective capacity and a number of blocks marked as the restricted block to the expectedly used capacity to determine whether to prohibit programming to the memory.   
     
     
         9 . The method of  claim 8 , further comprising:
 when the effective capacity is larger than the declared capacity, marking one of the blocks by the controller as the damaged block if the block is determined as in the non-use status; and   when the effective capacity is equal to the declared capacity, marking one of the blocks by the controller as the restricted block if the block is determined as in the non-use status.   
     
     
         10 . The method of  claim 8 , further comprising:
 when the expectedly used capacity is larger than the difference of the effective capacity and the number of blocks marked as the restricted block, prohibiting, by the controller, programming to the memory; and   when the expectedly used capacity is not larger than the difference of the effective capacity and the number of blocks marked as the restricted block, permitting, by the controller, programming to the memory.   
     
     
         11 . The method of  claim 8 , further comprising:
 sending a warning signal by the controller when the expectedly used capacity is larger than the difference of the effective capacity and the number of blocks marked as the restricted block.   
     
     
         12 . The method of  claim 8 , further comprising:
 when the expectedly used capacity is larger than the difference of the effective capacity and the number of blocks marked as the restricted block, transmitting, by the controller, a warning signal, the expectedly used capacity, and the difference of the effective capacity and the number of blocks marked as the restricted block to an electronic device; and   prohibiting, by the electronic device, programming to the memory and displaying a to-be-cleared capacity in response to the warning signal.   
     
     
         13 . The method of  claim 8 , wherein the declared capacity is an initial capacity of the storage device after being initialized. 
     
     
         14 . A method of storage space management for a storage device, the storage device comprising a controller and a memory, the storage device having a declared capacity, the method comprising:
 storing, by the controller, at least one re-initialization capacity, wherein the at least one re-initialization capacity is less than the declared capacity;   calculating, by the controller, an effective capacity, wherein the effective capacity has a negative correlation with a number of blocks among a plurality of blocks of the memory marked as bad blocks; and   determining, by the controller, based on a difference between the effective capacity and the declared capacity, whether to enable the storage device to re-initialize with the at least one re-initialization capacity.   
     
     
         15 . The method of  claim 14 , wherein the storage device has a table of declared capacities comprising a plurality of capacities for re-initialization, the method further comprising:
 when the effective capacity is less than or equal to the declared capacity, selecting one of the capacities less than the declared capacity for re-initialization to perform re-initialization.