Bad Block Table

David Woodhouse dwmw2 at
Tue Mar 28 04:37:40 EST 2000

dviro at said:
>  1.  Where is it located?  Oron from M-Systems said that before erase
> the flash it is important to save it.  So where is it located, and how
> can I save it? (Will dd work?) 

Stored in the same erase block as the NFTL Media Header(s). 
Look for BadUnitTable in util/nftl_format.c

dviro at said:
>  2.  Also mentioned was that during the lifetime of the flash, if a
> new bad block is found, it is marked as a bad block.  This will be
> effective only before doing a boot.  Question is, who is responsible
> for finding those bad blocks - the M-Systems kernel driver?

This is effective only until you next reboot - i.e. it's not written to the 
BadUnitTable, only stored in memory. Presumably, the M-Systems driver notices 
a failure when it tries to erase or write a block, and marks it bad.

dviro at said:
>  3.  And if the driver is responsible for this, does the MTD driver do
> the same? 

Not yet.


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