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10 Cards in this Set
- Front
- Back
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List the layers of a file management system (FMS).
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file control (sw)
storage i/o control (hw) |
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What is the difference between the logical and physical structure of a file?
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logical: fields and records
physical: actual bits |
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What advantages are realized by not having an application program interact directly with physical file structure?
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Simplification via abstraction. They need no knowledge of storage allocation issues and no programming dependent thereon.(aka black box)
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What file types usually are supported directly by a file management system?
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text,
executable, and command (JCL) [TEC] |
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What is an allocation unit?
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The smallest portion of storage device or medium.
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What are the advantages of using small allocation units?
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Efficient use of space. Little space is wasted.
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What are the disadvantages of using small allocation units?
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Additional processing required due to extra data structures.
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Describe the use of buffers in file I/O operations.
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convert physical records into logical records
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When are buffers allocated? When are the released?
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Buffers are allocated when a file is opened and released when a file is closed.
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Describe the structure of a hierarchical directory?
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In a hierarchical directory each directory node may be a file or an embedded subdirectory. Subdirectories may be nested to an arbitrary depth.
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