The first disk operating systems for the Apple II were DOS 3.1 and DOS 3.2 organized into 35 tracks of 13 256 - byte sectors each .
3.2 stored 113.75 kB on each disk .
The first disk operating systems for the Apple II were DOS 3.1 and DOS 3.2 , which stored 113.75 kB on each disk , organized into 35 tracks of 13 256 - byte sectors each .