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Diff between File system and FAT file system

keil Enthu

Hi to all, i started to work on FAT file system on SD 1GB card. LPC2388 on MCB2300 board.

Just now i have completed my binary search on File system on SD card. Simply fopen, fread, fseek,etc.

Now i have to work on SD card using FAT file system. i went through so many web pages that didnt answer my question or i was not able to understand.

how to make a File allocating table on my SD Card? Some simple example can give me a good start...

my question is Whats the difference between Normal File system (which i have done on my SD card) and FAT File system?

And I had formatted the SD card on LAPTOP with the 2 options of FAT(Default) and FAT32.
When i tried to use the card after i did format using FAT(Default) option, i was able to work with my code which i developed for SD card using normal File system.

But if format using FAT32 option, then while trying to initialize the card it says SD card un formatted.

So what its trying to say?

So by default my controller accept FAT12?

Can i use FAT32 on the same SD card for my same code in which i didnt give an option to recognize FAT32?

As i studied from the web source for FAT16, the clusters address divide my SD card in to sectors and gives back the location address to me(2^16 address)?

So on for FAT32?

So please give me some clear explanation how to start? And i gone through Wikipedia and all the sources so dont give me the link for wikipedia pls.

Parents
  • 0 in reply to Tamiryan Michael

    but how could you, without implementing your own FAT FS?
    please explain and try to focus your questions to the core issues - what EXACTLY are you trying to do?

    y did i say that means I didnt create any clusters, volume , drive and directory. by default it may be FAT12 i think.

    In the file_config.c i made my default drive as memory card drive.

    i was using RT Agent and File_config.h which provided by RL ARM.

    So i was directly influenced by create anything.

    So as you said should i have a FAT to implement a file system?
    My code working well. So what FAT's role over there?

    When ever i need a data i just fopen, fread and fseek with the data what ever i need. if a match occurs simply i read the data from that location using offset..

            FILE *loc;
        FILE *dat;
        loc = fopen ("Index.txt", "r");
        dat = fopen ("UserLocation.txt", "r");

    then i do the Binary searching

            mid = (begin + end) / 2;
                offset = mid;

            fseek (loc, offset * 2, SEEK_SET);
            fread (&count2[0], 2, 1, loc);

                location = count2[0];

            fseek (dat, location * 4, SEEK_SET);
                fread (&First_fourByte[0], 4, 1, dat);

    Then normal C code...

    I think i did not understand the FAT FS well. I know there might be some good for me when i understand it fully. Where i am using FAT here?

Reply
  • 0 in reply to Tamiryan Michael

    but how could you, without implementing your own FAT FS?
    please explain and try to focus your questions to the core issues - what EXACTLY are you trying to do?

    y did i say that means I didnt create any clusters, volume , drive and directory. by default it may be FAT12 i think.

    In the file_config.c i made my default drive as memory card drive.

    i was using RT Agent and File_config.h which provided by RL ARM.

    So i was directly influenced by create anything.

    So as you said should i have a FAT to implement a file system?
    My code working well. So what FAT's role over there?

    When ever i need a data i just fopen, fread and fseek with the data what ever i need. if a match occurs simply i read the data from that location using offset..

            FILE *loc;
        FILE *dat;
        loc = fopen ("Index.txt", "r");
        dat = fopen ("UserLocation.txt", "r");

    then i do the Binary searching

            mid = (begin + end) / 2;
                offset = mid;

            fseek (loc, offset * 2, SEEK_SET);
            fread (&count2[0], 2, 1, loc);

                location = count2[0];

            fseek (dat, location * 4, SEEK_SET);
                fread (&First_fourByte[0], 4, 1, dat);

    Then normal C code...

    I think i did not understand the FAT FS well. I know there might be some good for me when i understand it fully. Where i am using FAT here?

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