Browse Prior Art Database

Alternative Block Assignment in Silicon Disk

IP.com Disclosure Number: IPCOM000105336D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Asano, H: AUTHOR

Abstract

Describes is a method to assign a permanent error area to an alternative area in the same sector. This method is useful for the memories which has limited write endurance, such as FLASH EEPROM.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Alternative Block Assignment in Silicon Disk

      Describes is a method to assign a permanent error area to an
alternative area in the same sector.  This method is useful for the
memories which has limited write endurance, such as FLASH EEPROM.

      Memories such as FLASH EEPROM degrade if the write operation
are repetitively performed into the same area.  Therefore the
assignment of a particular sector area as an alternative sector
increases the degradation speed because the normal alternative sector
assignment uses two write operations in one write.  This method will
not increase the degradation with the alternative assignment by
assigning the alternative area in the same sector area.  This is
realized by dividing a sector into multiple sub-sectors.  This method
is also effective in resolving the problem of controlling the
alternative pointer and power-off during the write operation for the
sectors which need the alternative area.

      This method may employ a block structure described in [*].
Fig. 1 shows an example of the structure in which one block or sector
has 576 bytes and is divided into a block information area of 64
bytes and a data area of 512 bytes.  In the block information area,
26 bytes are assigned to ID, ECC write information, and remaining 38
bytes are reserved for the alternative areas.

      Fig. 2 shows an example of the 38 byte alternative area in
which an alternative sub-block is created whenever an error having a
length shorter than a predetermined length is found in the d...