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Summary of Section 10.1: Files

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File Concept

• A file is a named collection of data stored on secondary storage.
• Managed by the file system (FS), which provides a high-level interface for users.
• File Access Methods:
  • Sequential Access: Reads/writes in order (e.g., text files).
  • Direct Access: Jumps to a specific record (used in databases).
  • Byte-Oriented Access: Reads/writes a specific number of bytes.
  • Record-Oriented Access: Reads/writes structured records.

🔹 Benefit: Users interact with files without worrying about hardware details.

File Types

• Data and Metadata:
  • Data → Visible content of a file.
  • Metadata → Stored in a file header (format, structure).
• Identifying File Types:
  1. Magic Number (hidden inside the file header).
  2. File Extension (e.g., .txt, .exe).
• Weak vs. Strong Typing:
  • Weak Typing: OS guesses file type from extension (e.g., Windows).
  • Strong Typing: OS uses magic numbers to enforce correct handling.

🔹 Example: Renaming a .docx file to .txt may still open in Word but could be unreadable in Notepad.

Exercises and Applications

• Comparing Access Methods:
  • Determine which methods apply to different file types.
• File Type Recognition:
  • Analyze how extensions and magic numbers affect file handling.
• Enforcing File Types:
  • Compare weak vs. strong file typing.

This section explains file management, access methods, and file type identification, focusing on user interaction and OS enforcement.