Operating Systems 2019W: Assignment 2 - Revision history

https://homeostasis.scs.carleton.ca/wiki/index.php?action=history&feed=atom&title=Operating_Systems_2019W%3A_Assignment_2 Operating Systems 2019W: Assignment 2 - Revision history 2026-04-05T16:59:58Z Revision history for this page on the wiki MediaWiki 1.42.1 https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22205&oldid=prev Soma at 21:04, 11 February 2019 2019-02-11T21:04:50Z

<p></p> <a href="https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22205&oldid=22204">Show changes</a>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22204&oldid=prev Soma: /* Questions */ 2019-02-10T04:15:00Z

<p><span dir="auto"><span class="autocomment">Questions</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:15, 10 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l33">Line 33:</td> <td colspan="2" class="diff-lineno">Line 33:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''EXTRA CREDIT (4 points):''' Make a file write-upper.bin that, when loaded by 3000run-write, writes out the upper case version of the string given as the second argument. You may modify the passed in string.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''EXTRA CREDIT (4 points):''' Make a file write-upper.bin that, when loaded by 3000run-write, writes out the upper case version of the string given as the second argument. You may modify the passed in string.</div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">If you submit the extra credit question, please upload your file write-upper.bin along with a text file containing the rest of your answers in a zip file (named like the text file, but with a .zip extension). You should include the text of the assembly (or C code) of your program and explain how you used it to create write-upper.bin.</ins></div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22195&oldid=prev Soma: /* Questions */ 2019-02-04T22:21:02Z

<p><span dir="auto"><span class="autocomment">Questions</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 22:21, 4 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l17">Line 17:</td> <td colspan="2" class="diff-lineno">Line 17:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Is it normally safe to say yes to this question? Why?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Is it normally safe to say yes to this question? Why?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Describe a situation when you should say no. Give a specific example of a "bad thing" that could be happening.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Describe a situation when you should say no. Give a specific example of a "bad thing" that could be happening.</div></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># [3] Modify [https://homeostasis.scs.carleton.ca/~soma/os-2017f/code/tut3/3000test.c 3000test.c] so it can report on what access the current user has to the file. Give your code as a "diff -c" relative to the original 3000test.c.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># [3] Modify [https://homeostasis.scs.carleton.ca/~soma/os-2017f/code/tut3/3000test.c 3000test.c] so it can report on what access the current user has to the file. Give your code as a "diff -c" relative to the original 3000test.c. <ins style="font-weight: bold; text-decoration: none;">(You may ignore groups.)</ins></div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [3] Create a program 3000run-write.c (based on 3000test.c) that attempts to run the contents of a (specific) file by mmap'ing it into an array, converting the array pointer into a function pointer, and then calling the function. The called function should have the same declaration as write(), and you should call it with three arguments: 1, "Hello there!\n", and 13. When your program is given the file [https://homeostasis.scs.carleton.ca/~soma/os-2019w/code/write.bin write.bin] as a command-line argument, it should print out "Hello there!" to standard out (the terminal). Give the code of 3000run-write as a "diff -c" versus the original 3000test.c.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [3] Create a program 3000run-write.c (based on 3000test.c) that attempts to run the contents of a (specific) file by mmap'ing it into an array, converting the array pointer into a function pointer, and then calling the function. The called function should have the same declaration as write(), and you should call it with three arguments: 1, "Hello there!\n", and 13. When your program is given the file [https://homeostasis.scs.carleton.ca/~soma/os-2019w/code/write.bin write.bin] as a command-line argument, it should print out "Hello there!" to standard out (the terminal). Give the code of 3000run-write as a "diff -c" versus the original 3000test.c.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] You run the commands below, replacing <scs-username> with your SCS username. After running these commands (and assuming the sshfs command succeeds), how many copies of "test.txt" exist? Where are they stored?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] You run the commands below, replacing <scs-username> with your SCS username. After running these commands (and assuming the sshfs command succeeds), how many copies of "test.txt" exist? Where are they stored?</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22185&oldid=prev Soma at 18:54, 1 February 2019 2019-02-01T18:54:05Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:54, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">'''This assignment is not yet finalized.'''</del></div></td><td colspan="2" class="diff-side-added"></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2" class="diff-side-added"></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Please submit the answers to the following questions via CULearn by 4 PM on Monday, February 11, 2019. There are 20 points in 9 questions (and 4 points extra credit).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Please submit the answers to the following questions via CULearn by 4 PM on Monday, February 11, 2019. There are 20 points in 9 questions (and 4 points extra credit).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22184&oldid=prev Soma: /* Questions */ 2019-02-01T18:51:28Z

<p><span dir="auto"><span class="autocomment">Questions</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 18:51, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l11">Line 11:</td> <td colspan="2" class="diff-lineno">Line 11:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Questions==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Questions==</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># [2] Assume you have a file A. You type <tt>ln A B</tt> in order to create file B. If you delete A, what happens when you try to read <del style="font-weight: bold; text-decoration: none;">A</del>? Why?</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># [2] Assume you have a file A. You type <tt>ln A B</tt> in order to create file B. If you delete A, what happens when you try to read <ins style="font-weight: bold; text-decoration: none;">B</ins>? Why?</div></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># [2] Assume you have a file A. You type <tt>ln -s A B</tt> in order to create file B. If you delete A, what happens when you try to read <del style="font-weight: bold; text-decoration: none;">A</del>? Why?</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># [2] Assume you have a file A. You type <tt>ln -s A B</tt> in order to create file B. If you delete A, what happens when you try to read <ins style="font-weight: bold; text-decoration: none;">B</ins>? Why?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] What does fsck do if it finds an allocated inode that no file refers to? How could this problem arise?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] What does fsck do if it finds an allocated inode that no file refers to? How could this problem arise?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Describe a situation where a UNIX sparse file could cause problems for a backup program (that didn't specially treat sparse files).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Describe a situation where a UNIX sparse file could cause problems for a backup program (that didn't specially treat sparse files).</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22183&oldid=prev Soma at 05:34, 1 February 2019 2019-02-01T05:34:10Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:34, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''This assignment is not yet finalized<del style="font-weight: bold; text-decoration: none;">. Please do not answer these questions yet, they are subject to change</del>.'''</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''This assignment is not yet finalized.'''</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Please submit the answers to the following questions via CULearn by 4 PM on Monday, February 11, 2019. There are 20 points in 9 questions (and 4 points extra credit).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Please submit the answers to the following questions via CULearn by 4 PM on Monday, February 11, 2019. There are 20 points in 9 questions (and 4 points extra credit).</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22182&oldid=prev Soma: /* Questions */ 2019-02-01T05:33:41Z

<p><span dir="auto"><span class="autocomment">Questions</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:33, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l34">Line 34:</td> <td colspan="2" class="diff-lineno">Line 34:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> rm -f scs-files/testdir/test.txt</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> rm -f scs-files/testdir/test.txt</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''EXTRA CREDIT (4 points):''' Make a file write-upper.bin that, when loaded by 3000run-write, writes out the upper case version of the string given as the second argument.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''EXTRA CREDIT (4 points):''' Make a file write-upper.bin that, when loaded by 3000run-write, writes out the upper case version of the string given as the second argument<ins style="font-weight: bold; text-decoration: none;">. You may modify the passed in string</ins>.</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22181&oldid=prev Soma: /* Questions */ 2019-02-01T05:31:55Z

<p><span dir="auto"><span class="autocomment">Questions</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:31, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l34">Line 34:</td> <td colspan="2" class="diff-lineno">Line 34:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> rm -f scs-files/testdir/test.txt</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> rm -f scs-files/testdir/test.txt</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''EXTRA CREDIT (4 points):''' Make a file upper.bin that, when loaded by 3000run, <del style="font-weight: bold; text-decoration: none;">prints </del>out the upper case version of the string given as <del style="font-weight: bold; text-decoration: none;">an </del>argument.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''EXTRA CREDIT (4 points):''' Make a file <ins style="font-weight: bold; text-decoration: none;">write-</ins>upper.bin that, when loaded by 3000run<ins style="font-weight: bold; text-decoration: none;">-write</ins>, <ins style="font-weight: bold; text-decoration: none;">writes </ins>out the upper case version of the string given as <ins style="font-weight: bold; text-decoration: none;">the second </ins>argument.</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22180&oldid=prev Soma at 05:29, 1 February 2019 2019-02-01T05:29:49Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:29, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l15">Line 15:</td> <td colspan="2" class="diff-lineno">Line 15:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] What does fsck do if it finds an allocated inode that no file refers to? How could this problem arise?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] What does fsck do if it finds an allocated inode that no file refers to? How could this problem arise?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Describe a situation where a UNIX sparse file could cause problems for a backup program (that didn't specially treat sparse files).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Describe a situation where a UNIX sparse file could cause problems for a backup program (that didn't specially treat sparse files).</div></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"># [3] Modify [https://homeostasis.scs.carleton.ca/~soma/os-2017f/code/tut3/3000test.c 3000test.c] so it can report on what access the current user has to the file. Give your code as a "diff -c" relative to the original 3000test.c.</del></div></td><td colspan="2" class="diff-side-added"></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"># [3] Create a program 3000run.c (based on 3000test.c) that attempts to run the contents of a file by mmap'ing it into an array, converts the array pointer into a function pointer for a function that takes one argument, a standard C string (char *) and then calls the function, passing it a string. Test your code on [https://homeostasis.scs.carleton.ca/~soma/os-2019w/code/print.bin print.bin] which contains the machine code for a function that prints the given string to standard out.</del></div></td><td colspan="2" class="diff-side-added"></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Is a filesystem's superblock accessed frequently in normal operation? Why or why not?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Is a filesystem's superblock accessed frequently in normal operation? Why or why not?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] When first connecting to a remote host via ssh, you will normally get a message saying something similar to this: "The authenticity of host 'access.scs.carleton.ca (134.117.29.72)' can't be established. RSA key fingerprint is SHA256:MexEKZF0Os0Vl6VTObN70lRf2DFsGfD8DTQ7FKKqVJ4. Are you sure you want to continue connecting (yes/no)?"</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] When first connecting to a remote host via ssh, you will normally get a message saying something similar to this: "The authenticity of host 'access.scs.carleton.ca (134.117.29.72)' can't be established. RSA key fingerprint is SHA256:MexEKZF0Os0Vl6VTObN70lRf2DFsGfD8DTQ7FKKqVJ4. Are you sure you want to continue connecting (yes/no)?"</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Is it normally safe to say yes to this question? Why?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Is it normally safe to say yes to this question? Why?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Describe a situation when you should say no. Give a specific example of a "bad thing" that could be happening.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>#* Describe a situation when you should say no. Give a specific example of a "bad thing" that could be happening.</div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"># [3] Modify [https://homeostasis.scs.carleton.ca/~soma/os-2017f/code/tut3/3000test.c 3000test.c] so it can report on what access the current user has to the file. Give your code as a "diff -c" relative to the original 3000test.c.</ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"># [3] Create a program 3000run-write.c (based on 3000test.c) that attempts to run the contents of a (specific) file by mmap'ing it into an array, converting the array pointer into a function pointer, and then calling the function. The called function should have the same declaration as write(), and you should call it with three arguments: 1, "Hello there!\n", and 13. When your program is given the file [https://homeostasis.scs.carleton.ca/~soma/os-2019w/code/write.bin write.bin] as a command-line argument, it should print out "Hello there!" to standard out (the terminal). Give the code of 3000run-write as a "diff -c" versus the original 3000test.c.</ins></div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] You run the commands below, replacing <scs-username> with your SCS username. After running these commands (and assuming the sshfs command succeeds), how many copies of "test.txt" exist? Where are they stored?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] You run the commands below, replacing <scs-username> with your SCS username. After running these commands (and assuming the sshfs command succeeds), how many copies of "test.txt" exist? Where are they stored?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2019W:_Assignment_2&diff=22179&oldid=prev Soma at 04:08, 1 February 2019 2019-02-01T04:08:41Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:08, 1 February 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l15">Line 15:</td> <td colspan="2" class="diff-lineno">Line 15:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] What does fsck do if it finds an allocated inode that no file refers to? How could this problem arise?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] What does fsck do if it finds an allocated inode that no file refers to? How could this problem arise?</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Describe a situation where a UNIX sparse file could cause problems for a backup program (that didn't specially treat sparse files).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Describe a situation where a UNIX sparse file could cause problems for a backup program (that didn't specially treat sparse files).</div></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div># [3] Modify 3000test.c so it can report on what access the current user has to the file. Give your code as a "diff -c" relative to the original 3000test.c.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># [3] Modify <ins style="font-weight: bold; text-decoration: none;">[https://homeostasis.scs.carleton.ca/~soma/os-2017f/code/tut3/3000test.c </ins>3000test.c<ins style="font-weight: bold; text-decoration: none;">] </ins>so it can report on what access the current user has to the file. Give your code as a "diff -c" relative to the original 3000test.c.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [3] Create a program 3000run.c (based on 3000test.c) that attempts to run the contents of a file by mmap'ing it into an array, converts the array pointer into a function pointer for a function that takes one argument, a standard C string (char *) and then calls the function, passing it a string. Test your code on [https://homeostasis.scs.carleton.ca/~soma/os-2019w/code/print.bin print.bin] which contains the machine code for a function that prints the given string to standard out.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [3] Create a program 3000run.c (based on 3000test.c) that attempts to run the contents of a file by mmap'ing it into an array, converts the array pointer into a function pointer for a function that takes one argument, a standard C string (char *) and then calls the function, passing it a string. Test your code on [https://homeostasis.scs.carleton.ca/~soma/os-2019w/code/print.bin print.bin] which contains the machine code for a function that prints the given string to standard out.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Is a filesystem's superblock accessed frequently in normal operation? Why or why not?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div># [2] Is a filesystem's superblock accessed frequently in normal operation? Why or why not?</div></td></tr> </table>

Soma