Explain the data structures and algorithms that you would use to design an in-memory file system. Illustrate with an example in the code logic where possible.
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A file system, in its most simplistic version, consists of Files and Directories. Each Directory contains a set of Files and Directories. Since Files and Directories share so many characteristics, we’ve implemented them such that they inherit from the same class, Entry.
Implemented Main logic in Java
Alternatively, we could have implemented Directory such that it contains separate lists for files and subdirectories. This makes the nurnberOfFiles () method a bit cleaner, since it doesn’t need to use the instanceof operator, but it does prohibit us from cleanly sorting files and directories by dates or names.
For data block allocation, we can use bitmask vector and linear search (see “Practical File System Design”) or B+ trees (see Reference or Wikipedia).
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