10.1 Consider a file system where a file can be deleted and its disk space reclaimed while links to that file still exist. What problems may occur if a new file is created in the same storage area or with the same absolute path name? How can these problems be avoided?

a. 记录引用。两种策略：

1. 级联删除到它的链接。
1. 禁止删除正在被链接的文件。


b. 每个文件分配一个唯一的索引号，新文件的索引号不同，因此访问对旧文件的链接时，发现文件不存在，则可以删除此链接。

10.4 What are the advantages and disadvantages of recording the name of the creating program with the file’s attributes (as is done in the Macintosh Operating System)?

10.6 If the operating system were to know that a certain application is going to access the file data in a sequential manner, how could it exploit this information to improve performance?