Here's a DOS 3.3 System Master disk. It's really easy
to see that the "Boot Blocks" take up three whole tracks,
and the Volume Bitmap is at track $11, sector $0, and the VTOC
(Volume Table Of Contents) occupies the rest of track $11. Interestingly,
you can see how files are allocated on a DOS disk, they go one
per track, starting at sector $F and working their way down, so
there are lots of extent blocks at sector $F. You may recognize
the track and sector labels from Copy ][+, of which I am a fan.