Lpc2000

Try

http://alumnus.caltech.edu/~pje/rdcf2.txt

It works !

Regards,

        Martin

----- Original Message ----- 
From: "Bogdan Teodorescu" <bteo@...>
To: <lpc2000@yahoogroups.com>
Sent: Friday, November 11, 2005 7:26 AM
Subject: Re: [lpc2000] Re: Cheap SD Flash File System


> Hello,
> I am not able to open http://alumnus.caltech.edu/~pje/rdcf2.txt`
> Does anybody knows were to find those files ?
> Thanks
> Bogdan
> ----- Original Message ----- 
> From: "rtstofer" <rstofer@...>
> To: <lpc2000@yahoogroups.com>
> Sent: Friday, November 11, 2005 1:17 AM
> Subject: [lpc2000] Re: Cheap SD Flash File System
>
>
>> --- In lpc2000@yahoogroups.com, "Dan Beadle" <dan.beadle@i...> wrote:
>>>
>>> When you delete an entry in the DIR by writing E5 to the first
>> byte, you
>>> must first deallocate all used sectors.
>>
>> I don't think so.  If you deallocate at that point, you can never
>> recover the file and an entire aftermarket software industry would
>> crash and burn.  I gotta think about this...  Perhaps the sectors
>> are unallocated when the directory entry is used for a new file.
>>
>> Anyway, deallocating a used cluster would be done by writing
>> 0x00000000 to the cluster entry in the FAT?
>>
>>>
>>>
>>> (If you don't, you have to old DOS problem of lost clusters)
>>>
>>>
>>>
>>> Delete File:
>>>
>>>             Starting at First Cluster,  (from Dir entry)
>>>
>>>                         Walk through the cluster allocation table,
>>> unlinking each cluster from the file (returning to free)
>>
>> Again, by writing 0x00000000?  Or is there a linked list of free
>> clusters?  If so, I missed that somehow!  Or do I just wander around
>> in the FAT looking for a 0x00000000 entry?  Maybe the closest one
>> above the current cluster?
>>
>>>
>>>             Then mark first byte of file name to E5.
>>>
>>>
>>>
>>>
>>>
>>> As for writing, it is just the reverse...
>>>
>>>
>>>
>>> Make sure the files does not exist, if it does, delete it per
>> above.
>>>
>>>
>>>
>>> Search the directory for an entry starting in NULL or 0xE5
>> (previously
>>> deleted)
>>>
>>> Fill in your information in that structure. (File names are fixed
>> size,
>>> not null terminated. Pad with blanks)
>>>
>>> Find a free cluster from the Cluster Allocation Table.
>>>
>>> Put that entry into the Dir.
>>>
>>> Mark that cluster as EOF (FFFF) in the CAT
>>>
>>> Write the first cluster of information.
>>
>> Dealing with sectors per cluster along the way...
>>
>>>
>>> If there is more, find another free cluster
>>>
>>>             Mark the new cluster as EOF in the Cat
>>>
>>>             Change the EOF on the prior cluster from EOF to point
>> to
>>> this cluster
>>>
>>>
>>>
>>> Repeat till end of file...
>>
>> No questions here...
>>
>>>
>>> Update the directory structure with file size, time (if desired).
>>>
>>>
>>
>> Yes, do this in close();  So, what do you do with the remaining
>> bytes in a partially filled sector and the remaining sectors in a
>> partially filled cluster?  My tendency from a security point of view
>> would be to fill them with 0's, or my personal favorite 0x5A.
>>
>> Richard
>>
>>
>>
>>
>>
>>
>>
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>