hw12_softupdates - can Some blocks might not have any...

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Homework: Reliable Files and Directories Read : Soft Updates Hand-In Procedure You are to turn in this homework at the beginning of lecture. Please write up your answers to the exercises below and hand them to a 6.828 staff member. Read over this homework and keep the questions in mind as you read the soft updates paper. Then come back and answer these questions. Reliable files and directories Consider what would need to be changed in xv6 to implement a write-back cache with proper ordering of writes. Identify all the calls to bwrite in xv6. (Hint: there are 7; use the cross-references.) For each call to bwrite, identify the other disk writes that must complete before that one
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Unformatted text preview: can. Some blocks might not have any dependencies, or might only have dependencies in certain cases. Turn in a list of bwrite calls and their dependencies, if any. Here are two calls, done for you: line 4132 (in balloc) no prerequisites line 4174 (in bfree) depends on corresponding bwrite at line 4167 Xv6 has no atomic rename; can there still be cycles in the block dependencies? This completes the homework. This assignment requires the files xv6.pdf and xv6_rev0.zip. You may download them from the Assignments page....
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