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| Here are some (unofficial) answers to the midterm practice questions
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| 1) False. Sparse file means holes. Zeroes aren't holes.
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| YOu need to move the file pointer. You have to use a
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| seek. The data will be READ as zeros, though...
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| Look up truncate command and strace it. It ain't just writing zeros
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| 2)
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| Nothing happens. Env vars aren't globals. They're passed in with Execve. Environments
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| variables are typically process specific.
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| 3)
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| rwx
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| 4)
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| Kill the parent
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| Why? init will own the zombie process and then kill it
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| 5)
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| chmod +x
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| Default non executable. Need to make it executable. (--x)
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| 6)
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| Software interrupt
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| 7)
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| Don't know... Undefined. Can not depend on ordering
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| 8)
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| True. That's the purpose of signals
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| Register a normal C function as a signal handler
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| Some are implemented by default (sigkill)
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| Signals can be called at any point in execution.
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| 9)
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| Sequentially (sysV). Shell script that runs every ''command'' sequentially
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| Upstart does in in parrallel though...
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| 10)
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| execve DOES NOT RETURN ANYTHING. Process image is replaced.
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| The program itself calls the signal handler
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| 11)
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| fsck <- wrapper function
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| fsck.FMT <- called by fsck for a specific format (ex: fsck.ext4)
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| 12)
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| The kernel. The kernel is the only thing that can allocate.(execve)
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| This also makes sense because execve is a system call.
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| 13)
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| Sparse file.
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| 14)
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| lspci, lshw.
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| In /proc/, you may be able to also.
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| These commands display the machine's "hardware".
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| Not /dev/ because that's the abstraction.
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| 15)
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| At the command line, the $PATH variable is where the shell looks for binaries/files.
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| The path is walked when the fullPATH/filename of the command line hasn't been specified
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| 16)
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| Some libraries make no sys calls (strlen). Libraries that do basic string and math
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| operations -> no sys calls
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| Programs with lots of I/O will use lot of sys calls
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| 17)
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| nice and renice
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| nicess is policy value (default value and you can modify this)
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| priority (dynamic) is based on niceness and the amount of time the process has run on
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| cpu
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| Priority doesn't apply to I/O. I/O will continue despite other processing having high
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| priority. I/O will always slow down the system.
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| 18)
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| The former requires a library card and a telephone.
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