Structure of .ST files

[Paolo]

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

[Guillaume Tello]

Post by Paolo
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.

Guillaume.

[Peter Dassow]

Post by Guillaume Tello

Post by Paolo
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

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.

[Charles Richmond]

Post by Peter Dassow

Post by Guillaume Tello

Post by Paolo
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

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.