理論上來(lái)講應(yīng)該是0x40才對(duì),但是現(xiàn)在我讀出不的兩個(gè)優(yōu)盤偏偏都是同樣的問(wèn)題,讀回的數(shù)據(jù)長(zhǎng)度為0,我應(yīng)該怎么辦?