+-------------------------+ | CS 3204 | | PROJECT 4: FILE SYSTEMS | | DESIGN DOCUMENT | +-------------------------+ ---- GROUP ---- >> Fill in the names and email addresses of your group members. FirstName LastName FirstName LastName FirstName LastName ---- PRELIMINARIES ---- >> If you have any preliminary comments on your submission, notes for the >> TAs, or extra credit, please give them here. >> Please cite any offline or online sources you consulted while >> preparing your submission, other than the Pintos documentation, course >> text, lecture notes, and course staff. INDEXED AND EXTENSIBLE FILES ============================ ---- DATA STRUCTURES ---- >> A1: Copy here the declaration of each new or changed `struct' or >> `struct' member, global or static variable, `typedef', or >> enumeration. Identify the purpose of each in 25 words or less. >> A2: What is the maximum size of a file supported by your inode >> structure? Show your work. ---- SYNCHRONIZATION ---- >> A3: Explain how your code avoids a race if two processes attempt to >> extend a file at the same time. >> A4: Suppose processes A and B both have file F open, both >> positioned at end-of-file. If A reads and B writes F at the same >> time, A may read all, part, or none of what B writes. However, A >> may not read data other than what B writes, e.g. if B writes >> nonzero data, A is not allowed to see all zeros. Explain how your >> code avoids this race. >> A5: Explain how your synchronization design provides "fairness". >> File access is "fair" if readers cannot indefinitely block writers >> or vice versa. That is, many processes reading from a file cannot >> prevent forever another process from writing the file, and many >> processes writing to a file cannot prevent another process forever >> from reading the file. ---- RATIONALE ---- >> A6: Is your inode structure a multilevel index? If so, why did you >> choose this particular combination of direct, indirect, and doubly >> indirect blocks? If not, why did you choose an alternative inode >> structure, and what advantages and disadvantages does your >> structure have, compared to a multilevel index? SUBDIRECTORIES ============== ---- DATA STRUCTURES ---- >> B1: Copy here the declaration of each new or changed `struct' or >> `struct' member, global or static variable, `typedef', or >> enumeration. Identify the purpose of each in 25 words or less. ---- ALGORITHMS ---- >> B2: Describe your code for traversing a user-specified path. How >> do traversals of absolute and relative paths differ? >> B3: Look over "pwd.c" in src/examples. Briefly explain how it >> determines the present working directory. ---- SYNCHRONIZATION ---- >> B4: How do you prevent races on directory entries? For example, >> only one of two simultaneous attempts to remove a single file >> should succeed, as should only one of two simultaneous attempts to >> create a file with the same name, and so on. >> B5: Does your implementation allow a directory to be removed if it >> is open by a process or if it is in use as a process's current >> working directory? If so, what happens to that process's future >> file system operations? If not, how do you prevent it? ---- RATIONALE ---- >> B6: Explain why you chose to represent the current directory of a >> process the way you did. BUFFER CACHE ============ ---- DATA STRUCTURES ---- >> C1: Copy here the declaration of each new or changed `struct' or >> `struct' member, global or static variable, `typedef', or >> enumeration. Identify the purpose of each in 25 words or less. ---- ALGORITHMS ---- >> C2: Describe how your cache replacement algorithm chooses a cache >> block to evict. >> C3: Describe your implementation of write-behind. >> C4: Describe your implementation of read-ahead. ---- SYNCHRONIZATION ---- >> C5: When one process is actively reading or writing data in a >> buffer cache block, how are other processes prevented from evicting >> that block? >> C6: During the eviction of a block from the cache, how are other >> processes prevented from attempting to access the block? ---- RATIONALE ---- >> C7: Describe a file workload likely to benefit from buffer caching, >> and workloads likely to benefit from read-ahead and write-behind. SURVEY QUESTIONS ================ Answering these questions is optional, but it will help us improve the course in future semesters. Feel free to tell us anything you want--these questions are just to spur your thoughts. You may also choose to respond anonymously in the course evaluations at the end of the quarter. >> In your opinion, was this assignment, or any one of the three problems >> in it, too easy or too hard? Did it take too long or too little time? >> Did you find that working on a particular part of the assignment gave >> you greater insight into some aspect of OS design? >> Is there some particular fact or hint we should give students in >> future quarters to help them solve the problems? Conversely, did you >> find any of our guidance to be misleading? >> Do you have any suggestions for the TAs to more effectively assist >> students in future quarters? >> Any other comments?