A standard DSK file is 143360 bytes long.
This is 35 tracks, each track is 4096 bytes.
Track Offset (HEX) Offset (Decimal) $00 $0 0 $01 $1000 4096 $02 $2000 8192 $03 $3000 12288 $04 $4000 16384 $05 $5000 20480 $06 $6000 24576 $07 $7000 28672 $08 $8000 32768 $09 $9000 36864 $0a $a000 40960 $0b $b000 45056 $0c $c000 49152 $0d $d000 53248 $0e $e000 57344 $0f $f000 61440 $10 $10000 65536 $11 $11000 69632 $12 $12000 73728 $13 $13000 77824 $14 $14000 81920 $15 $15000 86016 $16 $16000 90112 $17 $17000 94208 $18 $18000 98304 $19 $19000 102400 $1a $1a000 106496 $1b $1b000 110592 $1c $1c000 114688 $1d $1d000 118784 $1e $1e000 122880 $1f $1f000 126976 $20 $20000 131072 $21 $21000 135168 $22 $22000 139264