The key to many storage and retrieval techniques is the relative record number.
许多存储和检索技术的关键是相对记录号。
A relative record number indicates a record's position on the file.
相对记录编号指明了记录在文件上的位置。
Relative sector numbers are generated by counting from the physical file's first sector.
给出一个相对记录编号，可计算出相对扇区编号，给出相对扇区编号，
As the file is created, records are written, one at a time, in relative record number order.
当建立文件时按相对记录的编号顺序写入记录，每次写入一个。
The numbers indicate a given record's position relative to the first record in the file.
编号指明了一个给定的记录相对于文件中第一个记录的位置。
The file's first record (relative record 0) is at "start of file plus 0";
文件的第一个记录（相对记录编号为0）是在文件的起点上加0，
2.4 The Relative Record Concept
2.4 相对记录概念
For example, imagine a program has just finished processing relative record 14.
假设一个程序刚好处理完第14号相对记录，
a relatively wide magnetic tape for use in recording visual images and associated sound.
记录视觉图像和声音信号的相对宽的磁带。
How does this relate to the relative record number concept?
以上所述与相对记录编号的概念有何关系呢？
In our example, the relative record number indicates how many sectors away from the beginning of the file the record is stored.
在本例中，某个相对记录编号指明了该记录存放在从文件起点算起的第几号扇区上。
Note that the relative record number, a logical concept, and the relative sector number, it is possible to compute a relative sector number.
注意，相对记录编号（即一个逻辑概念）与相对扇区编号（即一个物理位置）是完全相同的。
We've already seen how a relative record number can be converted to a physical address;
我们已经明白了，相对记录编号如何才能转换成一个物理地址。
Relative record 10 is stored 10 sectors away, at track 30, sector 10.
第10号相对记录存放在离起点第10个扇区的第30磁道第10扇区上。
As Fig.8.7 shows, relative record 0 is stored at track 30, sector0; relative record 1 is at track 30, sector1; and so on.
如图8.7所示，第一号相对记录存放在第30磁道第一扇区上，如此等等。
A recorder pen makes a mark on a chart.
记录器的笔在记录卡上划一个记号。
An option is passing a numeric key to an algorithm and computing a relative record number.
还有一种选择就是把数值关键字传送给一个算法，然后算出一个相对记录编号。
The directory service has exhausted the pool of relative identifiers.
目录服务已经用完了相对标识号池。