운영체제 10장 연습문제

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운영체제 8장 연습문제 조선대학교 이준 교수님꺼

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Exercises
10.1 Consider a file system where a file can be deleted and its disk space
reclaimedwhile 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?
Answer: Let F1 be the old file and F2 be the new file. A userwishing
to access F1 through an existing link will actually access F2. Note that
the access protection for file F1 is used rather than the one associated
with F2.
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72 Chapter 10 File-System Interface
This problem can be avoided by insuring that all links to a deleted file
are deleted also. This can be accomplished in several ways:
a. maintain a list of all links to a file, removing each of them when
the file is deleted
b. retain the links, removing them when an attempt is made to
access a deleted file
c. maintain a file reference list (or counter), deleting the file only
after all links or references to that file have been deleted.
10.2 The open-file table is used to maintain information about files that are
currently open. Should the operating system maintain a separate table
for each user or just maintain one table that contains references to files
that are being accessed by all users at the current time? If the same file
is being accessed by two different programs or users, should there be
separate entries in the open file table?
Answer: By keeping a central open-file table, the operating system

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