Ro相对磁道号0Ri(1)R2(2)R3 (3)R4 (4)Rs(5)VOL1Ri(6)R2(7)R3(8)R4(9)Rs(10)R2R (11)R2(12)R3(13)R4(14)Rs(15)3R3 (18)R4 (19)R;(16)R2(17)Rs (20)...·......顺序文件Ri (n)R2(n+1)R3(n+2)R4(n+3)Rs(n+4)m-1mR2(n+6)R,(n+5)EOF未使用空间图7.5磁盘顺序文件图7.5 磁盘顺序文件