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Re: Structure of .ST files

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"Peter Dassow" <z80eu@arcor.de> wrote in message 
news:4f971782$0$6555$9b4e6d93@newsspool4.arcor-online.net...
> On 21.04.2012 15:39, Guillaume Tello wrote:
>> Le 21/04/2012 13:37, Paolo a écrit :
>>> Please, what is the structure of a .ST file emulating an Atari ST
>>> floppy disk?
>>> It gets 738.260 B versus 726.016 on the FD.
>>> Thanks
>>> Paul
>>
>> A standard floopy has:
>> 80 tracks with 9 sectors of 512 bytes on each side, so it is a total of:
>> 80*9*2*512 = 737 280 bytes.
>>
>> Some sectors are reserved for boot + FAT, so you only get 726 016 bytes
>> available for storage.
>>
>> 738260 - 737280 = 980 bytes added.
>> Well, I can't say more in this organisation of those 980 bytes.
>>
>
> It's similar to MS-DOS formatted floppy disks.
> You have a boot sector (512 Bytes), which is always not usable for data.
> And you have some File Allocation Table sectors, and last but not least a 
> few sectors for directory entries.
> How many sectors are used for FAT and Directory Entries is set by some 
> bytes/numbers in the mentioned boot sector.
>
> So this is no rocket science.

I believe that there are *two* copies of the FAT table, in case one becomes 
corrupted.

-- 
+<><><><><><><><><><><><><><><><><><><>+
|      Charles Richmond       numerist@aquaporin4.com     |
+<><><><><><><><><><><><><><><><><><><>+ 

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Structure of .ST files Paolo <pppaolo@email.it> - 2012-04-21 04:37 -0700
  Re: Structure of .ST files Guillaume Tello <houten.van@orange.fr> - 2012-04-21 15:39 +0200
    Re: Structure of .ST files Peter Dassow <z80eu@arcor.de> - 2012-04-24 23:13 +0200
      Re: Structure of .ST files "Charles Richmond" <netnews@aquaporin4.com> - 2012-04-25 18:26 -0500

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