Question

give an example of a scenario that might benefit from a file system supporting an append-only access write. b) give a scenario where choosing a large file system block size might be a benefit; give an example where it might be a disadvantage. c) what file allocation strategy is most appropriate for random access files? give an example implementation that uses the allocation strategy you answered. d) why are the direct blocks stored in the i-node itself? e) given that the maximum file size of combination of direct, single indirection, double indirection, and triple indirection in an i-node-based file system is approximately the same as a file system solely using triple indirection, why not simply use only triple indirection to locate all file blocks

Answer 1

File systems are designed with various access and storage strategies. Append-only access is ideal for log files, large block sizes favor multimedia file storage but can waste space with small files, indexed allocation suits random access files like in UNIX i-nodes, direct blocks in i-nodes provide efficient access to frequently accessed data, and a mix of direct and indirect blocks optimizes efficiency for both small and large files.

Step-by-step explanation:

The question addresses various concepts related to file systems in the context of Computers and Technology, specifically the design decisions and trade-offs involved in their implementation. To provide detailed answers:

1. An example of a scenario that might benefit from a file system supporting an append-only access write could be a logging system where records are constantly added, and historical data should not be modified to ensure data integrity and maintain an audit trail.
2. Choosing a large file system block size could benefit scenarios like storing and accessing large multimedia files where larger blocks reduce overhead. Conversely, it might be disadvantageous for systems predominately storing small files, as it could lead to increased internal fragmentation and wasted space.
3. The most appropriate file allocation strategy for random access files is an indexed allocation. An example implementation that uses this allocation strategy is the UNIX file system, where i-nodes contain pointers to file blocks.
4. Direct blocks are stored in the i-node itself to provide efficient access to the first few blocks of a file, which are often accessed frequently, thereby reducing the number of disk accesses needed to retrieve file data.
5. Even though a file system using solely triple indirection could theoretically address a similar maximum file size as one using a combination of direct, single, and double indirection, it's not typically used alone because it would make access to small files (which are common) less efficient. Direct blocks in the i-node allow quicker access for smaller files without the overhead of multiple layers of indirection.