以记录、区域或控制块中的任意起始点到另一个点之间的测量单位数。 The number of measuring units from an arbitrary starting point in a record, area, or control block, to some other point.
在一单位长度内包含的有用信息单位数。通常用每英寸多少单位表示。 The number of units of useful information contained within a linear dimension, usually expressed in units per inch.