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Okay, I've been having problems floppy IO in my OS using INT 13h. When I use function 8 (Get Drive Parameters), it says there are 18 sectors per track, right??? But then I wrote a test bootloader that would fill the the first sector of the second track with 0xFF, it wrote it at 0x4800 on the floppy, not at 0x2400 where it should've. And I'm sure I'm using a 1.44MB floppy, I've tried different disks also.

When I write to Track 0 Sector 18 (the end of the first track), it writes to 0x2200-0x23FF (which is right), but then I go to Track 1 Sector 1 and that's when it writes at 0x4800 instead of 0x2400. I know the disk(s) only have 18 sectors per track because when I tried to write at Track 0 Sector 19, INT 13h returned with an error. Does someone know what is going on?

You are forgetting about the 2 sides ! track 0 head 0 sectors 1-18 are 0x0000 - 0x23ff, track 0 head 1 sectors 1-18 are 0x2400 - 0x47ff, so track 1 head 0 sectors 1-18 are 0x4800 onwards, so your program is actually doing the right thing

Oh, tracks are bigger than heads! Thanks a ton!!!