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US006230234B1
(12) United States Patent ao) Patent No.: us 6,230,234 Bi
Estakhri et al. (45) Date of Patent: *May 8,2001
12/1996 Hasbun et al
2/1997 Sukegawa et al
* cited by examiner
Primary Examiner—Reginald G. Bragdon
(74) Attorney, Agent, or Firm—Law Offices of Imam
(57) ABSTRACT
A nonvolatile semiconductor mass storage system and architecture can be substituted for a rotating hard disk. The system and architecture avoid an erase cycle each time information stored in the mass storage is changed. Erase cycles are avoided by programming an altered data file into an empty mass storage block rather than over itself as a hard disk would. Periodically, the mass storage will need to be cleaned up. These advantages are achieved through the use of several flags, and a map to correlate a logical block address of a block to a physical address of that block. In particular, flags are provided for defective blocks, used blocks, and old versions of a block. An array of volatile memory is addressable according to the logical address and stores the physical address.
11 Claims, 5 Drawing Sheets
