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səhifə | 4/5 | tarix | 10.05.2022 | ölçüsü | 316,35 Kb. | | #57309 |
| Unix
Implementation Of File System - Directories contain file names and pointers
- Pointer is called an i-number (index number) of the file
- I-number references the information of the file in the system table
File Information - Owner name
- Protection bits
- Physical address of location on disk
- Size
- Time of modification
- Number of links to file
- Directory bit
- Special file bit
- “Large” or “small” bit
Efficiency of File System - File system provides satisfactory performance
- 7621 line test program
- Total time of 35.9 seconds, 212 lines per second
- Time taken for each element:
63.5% Assembler execution 20.0% Disk wait time 16.6% System overhead I/O Calls - Eliminate differences between different devices
- open(name, flag) and Create
- No user-visible automatic locks on files, unnecessary and insufficient
- Sufficient internal interlocks
- Files are sequential
- read(filep, buffer, count), write(filep, buffer, count)
- seek(filep, base, offset)
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