START OF FS

[boot sector here, 512 bytes]

FS header:

bytes	size	what
0	2	header magic number: 0xbeef
2	2	sector size, should be 512
4	2	number of sectors
6	?	sector bitmap
{ file 0 first sector, file 1 first sec, file 2 etc, 0 , 0 }

[padding until end of sector]

file header area:

bytes	size	what
0	2	file number: 0
2	2	next sector, 0 if non existient
4	2	data size
8	2	[reserved]
10	?	data, max size (sector size - 8)
?	?	padding to end of sector if needed

bytes	size	what
0	2	file number: 1
2	2	next sector, 0 if non existient
4	2	data size
8	2	[reserved]
10	?	data, max size (sector size - 8)
?	?	padding to end of sector if needed

... etc ...

bytes	size	what
0	2	file number: 255
2	2	next sector, 0 if non existient
4	2	data size
8	2	[reserved]
10	?	data, max size (sector size - 8)
?	?	padding to end of sector if needed

data area:

bytes	size	what
0	2	file number this belongs to: 0 
2	2	next sector, 0 if this is last sector
4	?	data, max size (sector size - 4)
?	?	padding to end of sector if needed

bytes	size	what
0	2	file number this belongs to: 0 
2	2	next sector, 0 if this is last sector
4	?	data, max size (sector size - 4)
?	?	padding to end of sector if needed

bytes	size	what
0	2	file number this belongs to: 0 
2	2	next sector, 0 if this is last sector
4	?	data, max size (sector size - 4)
?	?	padding to end of sector if needed

etc to end of FS