Method of writing, erasing, and controlling memory for memory device

• US 7,257,666 B2
• Filed: 03/01/2004
• Issued: 08/14/2007
• Est. Priority Date: 10/01/1993
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Itoh, Hiroyuki, Komatsu, Shinpei, Ishii, Yumi, Takehara, Masaru, Hayashi, Tomohiro, Shibazaki, Shogo
• Primary Examiner(s): Thai; Tuan V.
• Application Number:
  US10/788,336
• Publication Number:
  US 20040168017A1
• Time in Patent Office: 1,261 Days
• Field of Search: 711/100, 711/103, 711/154, 714/5
• US Class Current: 711/103
• CPC Class Codes: G11C 29/76 using address translation or modifications
• CPC Class Codes: G11C 29/765 in solid state disks
• CPC Class Codes: G11C 29/82 for EEPROMs

Abstract

Data transferred from a host computer to a memory device is written into sectors whose addresses in a memory area are decoded by a decode table. Old data to be updated by the above data is erased or marked with erase flags. At a predetermined point of time, in order to create free areas, necessary data is evacuated to a primary memory media and unnecessary data indicated by erase flags is erased by a unit of predetermined memory size. Part of the memory media which has become defective is marked with a defect flag, and is replaced by an alternate area. In doing so, the decode table is rewritten to arrange the memory area.

Claims

1. A method of managing a memory device having a plurality of flash memory chips, each provided with a plurality of blocks, a free block of the blocks being used for writing new data, a block having old data replaced by the new data being erased by a unit of one block, the method comprising:

writing the new data into one of the flash memory chips, wherein logical addresses are fixedly assigned to the flash memory chips, so that one of the flash memory chips to which a logical address of the new data is assigned, is invariably used for writing the new data, such that a physical location of the new data written is always in said same one of the flash memory chips.

2. A method of managing a memory device comprising:

fixedly assigning logical addresses to flash memory chips of the memory device; and

writing new data of a specific logical address into a respective flash memory chip of the flash memory chips to which the specific logical address is fixedly assigned, such that the respective flash memory chip is a same flash memory chip for a given new data, and a physical address of the new data written is always in the respective flash memory chip.

3. The method of claim 2, further comprising:

writing the given new data into blocks of the flash memory chip, by shifting a designated block within the flash memory chip.

4. A memory device comprising:

a plurality of flash memory chips, each chip comprising a plurality of blocks, wherein a free block of the blocks being used for writing new data; and

means for fixedly assigning logical addresses to the flash memory chips, and writing new data of a specific logical address into a respective flash memory chip of the flash memory chips to which the specific logical address is fixedly assigned, such that the respective flash memory chip is a same flash memory chip for a given new data, a physical location of the new data written is always in the respective flash memory chip.