operating-systems file-management
Definition
File Types
Operating systems distinguish between file types to determine how they should be handled, interpreted, and executed.
Regular Files
ASCII Files
Lines of text. Portable and editable with any text editor.
Binary Files
Arbitrary bit sequences. Includes:
- Data files: Specific to an application
- Executables: Programs the OS can run
Executable Format
Executable Structure
The OS must interpret the internal structure (e.g., ELF in Linux, PE in Windows):
- Magic Number: Bit pattern identifying the file type
- Header: Metadata (file size, entry point)
- Text Segment: Machine code instructions
- Data Segment: Initialised variables
- Symbol Table: Debugging and dynamic linking information
Directories
Directories
Special system files maintaining file system structure. Map file names to identifiers or metadata. See File Directory.
Special Files
Character Special Files
Represent devices managing data as a stream of characters (e.g., terminals, serial ports).
Block Special Files
Represent devices handling data in fixed-size blocks (e.g., hard disks).