tracks in a 3.5 floppy disk

If you are new to OS Development, plan on spending some time here first before going into the other forums.

Moderator: Moderators

Post Reply
mns
Posts: 5
Joined: Sat Aug 07, 2010 9:00 pm

tracks in a 3.5 floppy disk

Post by mns » Sun Jan 16, 2011 12:26 pm

please someone clarify this(forgive me if I'm asking a foolish question :oops: )
how many tracks in a 3.5 floppy disk?
is it 80x2 or 63 :?

in tute:Bootloaders 3 says,
"There is 18 sectors per track. There is 63 tracks total on floppy disks.

If this value is greater then 63, The Floppy Controller will generate an exception, because the sector does not exist. Because there is no handler for it, The CPU will generate a second fault exception, which will ultimately lead to a Triple Fault."

and,

The Media Descriptor Byte (bpbMedia) is a byte code that contains information about the disk. This byte is a Bit Pattern:
Bits 0: Sides/Heads = 0 if it is single sided, 1 if its double sided
Bits 1: Size = 0 if it has 9 sectors per FAT, 1 if it has 8.
Bits 2: Density = 0 if it has 80 tracks, 1 if it is 40 tracks.
Bits 3: Type = 0 if its a fixed disk (Such as hard drive), 1 if removable (Such as floppy drive)
Bits 4 to 7 are unused, and always 1.
0xF0 = 11110000 binary. This means it is a single sided, 9 sectors per FAT, 80 tracks

Post Reply