Here is simple case study of Flash doctor, in this case, we could study how to judge the Mark structure setting is correct and it main function.
Look at the following picture; it’s a small Flash chip, only 128MB capacity:
After “Save Task”, we could read data:
Then we begin the structure analysis. First we must choose the right “Standard Page Structure”, we have set some command standard page structure as default, then we just need to choose them one by one and view data, if the service data are regularly, that means the page structure is correct. As the following picture:
The service data are disorder, not the right page structure:
The service data are regular, which represent correct page structure:
(The above pictures not come from this flash, just as an example)
Now we have confirmed the “Standard Page Structure”:
Then we focus on “Service Block Size”, at the beginning, we took a mistake at the Mark Structure, set a wrong Mark structure, and we will discuss this mistake later, to understand if we get the wrong mark, what’s the main represents.
About the ID structure, we can see the clear ID bits, which help us confirm the ID structure very soon:
Found the regular number first:
Then change some pages, look at the transformation of those bits:
Compared the two bits, “01″ at 06 position is still but “84″ at 07 is changed, so we know the Byte Order is “Big Endia”.
The first setting:
Then we try to combine data:
We were amazing to see that only collect 11 total nodes, and no valid nodes at all. There must some errors, then we changed the “Data Collection Method”:
But the result was the same. Only 11 total nodes and no valid nodes.
Analysis this problem, we know there are many pages in the Flash chip, and the main function of Mark structure is used to judge whether this page is a valid one (ID structure is relation with how many data we could collect, not relation with the node). So there must some problems in the Mark structure.
Check the Mark structure, we found the mistake soon:
We set a wrong Mark position. Actually, the correct setting is the at 00 position or the 24 position:
Then we modified the wrong setting and combine data again:
Now we can see the collection is success, 2800 total nodes and 577 valid nodes.
And the following data recovery work is success:
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