Operating Systems 2014F: Assignment 6 - Revision history

https://homeostasis.scs.carleton.ca/wiki/index.php?action=history&feed=atom&title=Operating_Systems_2014F%3A_Assignment_6 Operating Systems 2014F: Assignment 6 - Revision history 2026-04-05T16:59:30Z Revision history for this page on the wiki MediaWiki 1.42.1 https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19568&oldid=prev Mbingham at 15:21, 12 December 2014 2014-12-12T15:21:44Z

<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 15:21, 12 December 2014</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;"><div># Logical size is 268435456 bytes (as reported by ls -l). Physical size is 262144 blocks (as reported by ls -ls). By default ls assumes blocks are 1K in size; thus the physical space taken up by the file is 262144 * 1024 = 268439552 bytes. In other words, the physical size is 4096 bytes larger than the logical size. Note ext4 by default uses 4K blocks.</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># Logical size is 268435456 bytes (as reported by ls -l). Physical size is 262144 blocks (as reported by ls -ls). By default ls assumes blocks are 1K in size; thus the physical space taken up by the file is 262144 * 1024 = 268439552 bytes. In other words, the physical size is 4096 bytes larger than the logical size. Note ext4 by default uses 4K blocks.</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># No - it consumes less space. The logical size stays the same, but now it only consumes 8798208 bytes. In other words the physical size is around 3.3% of the logical size! (Note mkfs.ext4 somehow inserted "holes" into the file.)</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># No - it consumes less space. The logical size stays the same, but now it only consumes 8798208 bytes. In other words the physical size is around 3.3% of the logical size! (Note mkfs.ext4 somehow inserted "holes" into the file.)</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;">fsck or </del>fsck.ext4 <del style="font-weight: bold; text-decoration: none;"> (fsck calls fsck</del>.<del style="font-weight: bold; text-decoration: none;">ext4 when it figures out </del>the <del style="font-weight: bold; text-decoration: none;">filesystem is ext4</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># fsck.ext4. <ins style="font-weight: bold; text-decoration: none;">Just using </ins>the <ins style="font-weight: bold; text-decoration: none;">fsck command alone on a regular file like foo (in this environment</ins>) <ins style="font-weight: bold; text-decoration: none;">will only display the usage options.</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># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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># /dev/loop0. This is a loop block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</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># /dev/loop0. This is a loop block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</div></td></tr> </table>

Mbingham https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19555&oldid=prev Soma at 16:04, 11 December 2014 2014-12-11T16:04:54Z

<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 16:04, 11 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l38">Line 38:</td> <td colspan="2" class="diff-lineno">Line 38:</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># The command "rsync -a -v /etc /mnt" synchronizes the contents of /etc to /mnt. Specifically it only copies the files from the source (/etc) to the destination (/mnt) if they need to be; files that are already the same in both locations are not touched. The -a option means archive (use recursion and grab almost everything and preserve as much file metadata as possible). The -v option says to be verbose; without it rsync runs quietly (unless it encounters an error). Note that with these options files that exist in the destination but not in the source are preserved. If you want extraneous files and directories to be deleted in the destination, add "--delete --force".</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># The command "rsync -a -v /etc /mnt" synchronizes the contents of /etc to /mnt. Specifically it only copies the files from the source (/etc) to the destination (/mnt) if they need to be; files that are already the same in both locations are not touched. The -a option means archive (use recursion and grab almost everything and preserve as much file metadata as possible). The -v option says to be verbose; without it rsync runs quietly (unless it encounters an error). Note that with these options files that exist in the destination but not in the source are preserved. If you want extraneous files and directories to be deleted in the destination, add "--delete --force".</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># Any files that were previously in /mnt before the mount command are now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are no longer accessible.</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># Any files that were previously in /mnt before the mount command are now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are no longer accessible.</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;"></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># conv=notrunc means that dd will not truncate the file after it is done writing; it leaves the rest of the file intact.</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># conv=notrunc means that dd will not truncate the file after it is done writing; it leaves the rest of the file intact.</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># error is: mount: you must specify the filesystem type</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># error is: mount: you must specify the filesystem type</div></td></tr> <tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l44">Line 44:</td> <td colspan="2" class="diff-lineno">Line 43:</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># Logical size is 1G. Physical size is 0. In contrast, physical size (when initially created) was just a bit larger than the logical size.</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># Logical size is 1G. Physical size is 0. In contrast, physical size (when initially created) was just a bit larger than the logical size.</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># The logical size stays the same. The physical size increases (to 33,968,128 bytes).</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># The logical size stays the same. The physical size increases (to 33,968,128 bytes).</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;"># Two parts:</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;">#* Every subdirectory added The command "man 2 stat" describes the stat API. For a full version of a C program parsing what stat returns (and a bit more) see: http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/stat.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;">#* A directory has a link count that starts at 2: one is the normal one coming from the entry in the parent directory, while the second comes from the "." entry (the directory links to itself). Every subdirectory added increases the link count by one, because of the .. entry in each subdirectory.</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;"># You need to create a program that reads a chunk of the file from the end of the file, counts the lines in it, and then repeats until it finds the position of the start of the number of lines to be output. It then should read and output the lines from that position in the file (potentially using previously read data or reading it again). See the file_lines() function in the GNU coreutils tail implementation: http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/tail.c#n481 Note that the rest of this implementation of tail handle things like reading from a pipe and reading the last lines of a file forever (the -f option).</ins></div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19554&oldid=prev Soma at 15:48, 11 December 2014 2014-12-11T15:48:25Z

<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 15:48, 11 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l39">Line 39:</td> <td colspan="2" class="diff-lineno">Line 39:</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># Any files that were previously in /mnt before the mount command are now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are no longer accessible.</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># Any files that were previously in /mnt before the mount command are now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are no longer accessible.</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># conv=notrunc means that dd will not truncate the file after it is done writing <del style="font-weight: bold; text-decoration: none;">- </del>it leaves <del style="font-weight: bold; text-decoration: none;">other data in </del>the file intact.</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># conv=notrunc means that dd will not truncate the file after it is done writing<ins style="font-weight: bold; text-decoration: none;">; </ins>it leaves <ins style="font-weight: bold; text-decoration: none;">the rest of </ins>the file intact.</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># error is: mount: you must specify the filesystem type</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># error is: mount: you must specify the filesystem type</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># fsck<del style="font-weight: bold; text-decoration: none;">?</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># fsck<ins style="font-weight: bold; text-decoration: none;">.ext4 foo (on some versions of fsck you may have to manually specify the location of a backup superblock)</ins></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># Logical size is 1G. Physical size is 0.</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># Logical size is 1G. Physical size is 0<ins style="font-weight: bold; text-decoration: none;">. In contrast, physical size (when initially created) was just a bit larger than the logical size</ins>.</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># The logical size stays the same. The physical size increases.</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># The logical size stays the same. The physical size increases <ins style="font-weight: bold; text-decoration: none;">(to 33,968,128 bytes)</ins>.</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19553&oldid=prev Soma: /* Solutions */ 2014-12-10T16:02:12Z

<p><span dir="auto"><span class="autocomment">Solutions</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 16:02, 10 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l37">Line 37:</td> <td colspan="2" class="diff-lineno">Line 37:</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># /dev/loop0. This is a loop block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</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># /dev/loop0. This is a loop block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</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># The command "rsync -a -v /etc /mnt" synchronizes the contents of /etc to /mnt. Specifically it only copies the files from the source (/etc) to the destination (/mnt) if they need to be; files that are already the same in both locations are not touched. The -a option means archive (use recursion and grab almost everything and preserve as much file metadata as possible). The -v option says to be verbose; without it rsync runs quietly (unless it encounters an error). Note that with these options files that exist in the destination but not in the source are preserved. If you want extraneous files and directories to be deleted in the destination, add "--delete --force".</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># The command "rsync -a -v /etc /mnt" synchronizes the contents of /etc to /mnt. Specifically it only copies the files from the source (/etc) to the destination (/mnt) if they need to be; files that are already the same in both locations are not touched. The -a option means archive (use recursion and grab almost everything and preserve as much file metadata as possible). The -v option says to be verbose; without it rsync runs quietly (unless it encounters an error). Note that with these options files that exist in the destination but not in the source are preserved. If you want extraneous files and directories to be deleted in the destination, add "--delete --force".</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># Any files that were previously in /mnt before the mount command <del style="font-weight: bold; text-decoration: none;">is </del>now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are <del style="font-weight: bold; text-decoration: none;">not </del>accessible.</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># Any files that were previously in /mnt before the mount command <ins style="font-weight: bold; text-decoration: none;">are </ins>now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are <ins style="font-weight: bold; text-decoration: none;">no longer </ins>accessible.</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> </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># conv=notrunc means that dd will not truncate the file after it is done writing - it leaves other data in the file intact.</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># conv=notrunc means that dd will not truncate the file after it is done writing - it leaves other data in the file intact.</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># error is: mount: you must specify the filesystem type</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># error is: mount: you must specify the filesystem type</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19552&oldid=prev Soma: /* Solutions */ 2014-12-10T16:01:29Z

<p><span dir="auto"><span class="autocomment">Solutions</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 16:01, 10 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l36">Line 36:</td> <td colspan="2" class="diff-lineno">Line 36:</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># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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># /dev/loop0. This is a loop block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</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># /dev/loop0. This is a loop block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</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> </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># <ins style="font-weight: bold; text-decoration: none;">The command "</ins>rsync -a -v /etc <ins style="font-weight: bold; text-decoration: none;">/mnt" synchronizes the contents of /etc to </ins>/mnt. <ins style="font-weight: bold; text-decoration: none;"> Specifically it only copies the files from the source </ins>(/etc<ins style="font-weight: bold; text-decoration: none;">) </ins>to <ins style="font-weight: bold; text-decoration: none;">the destination (</ins>/mnt<ins style="font-weight: bold; text-decoration: none;">) if they need to be; files that are already the same in both locations are not touched</ins>. <ins style="font-weight: bold; text-decoration: none;"> The </ins>-a <ins style="font-weight: bold; text-decoration: none;">option </ins>means archive (use recursion and grab almost <ins style="font-weight: bold; text-decoration: none;">everything and preserve as much file metadata as possible</ins>)<ins style="font-weight: bold; text-decoration: none;">. The </ins>-v <ins style="font-weight: bold; text-decoration: none;">option says to be </ins>verbose<ins style="font-weight: bold; text-decoration: none;">; without it rsync runs quietly (unless it encounters an error). Note that with these options files that exist in the destination but not in the source are preserved. If you want extraneous files and directories to be deleted in the destination, add "--delete --force"</ins>.</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># rsync -a -v /etc /mnt. <del style="font-weight: bold; text-decoration: none;">Synchronize </del>(<del style="font-weight: bold; text-decoration: none;">in this case, copy) contents of </del>/etc to /mnt. -a means archive (use recursion and grab almost <del style="font-weight: bold; text-decoration: none;">everythin</del>)<del style="font-weight: bold; text-decoration: none;">, </del>-v <del style="font-weight: bold; text-decoration: none;">is </del>verbose.</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># Any files that were previously in /mnt before the mount command is now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are not accessible.</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># Any files that were previously in /mnt before the mount command is now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are not accessible.</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># conv=notrunc means that dd will not truncate the file after it is done writing - it leaves other data in the file intact.</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># conv=notrunc means that dd will not truncate the file after it is done writing - it leaves other data in the file intact.</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19551&oldid=prev Soma: /* Solutions */ 2014-12-10T15:57:39Z

<p><span dir="auto"><span class="autocomment">Solutions</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 15:57, 10 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l35">Line 35:</td> <td colspan="2" class="diff-lineno">Line 35:</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># fsck or fsck.ext4 (fsck calls fsck.ext4 when it figures out the filesystem is ext4)</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># fsck or fsck.ext4 (fsck calls fsck.ext4 when it figures out the filesystem is ext4)</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># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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># /dev/loop0. This is a <del style="font-weight: bold; text-decoration: none;">loopback </del>block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device.</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># /dev/loop0. This is a <ins style="font-weight: bold; text-decoration: none;">loop </ins>block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device. <ins style="font-weight: bold; text-decoration: none;"> (NOTE: In class we referred to this as the "loopback block" device, but to reduce confusion it is normally referred to as the loop device.)</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;"><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># rsync -a -v /etc /mnt. Synchronize (in this case, copy) contents of /etc to /mnt. -a means archive (use recursion and grab almost everythin), -v is verbose.</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># rsync -a -v /etc /mnt. Synchronize (in this case, copy) contents of /etc to /mnt. -a means archive (use recursion and grab almost everythin), -v is verbose.</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19550&oldid=prev Soma at 15:43, 10 December 2014 2014-12-10T15:43:56Z

<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 15:43, 10 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l30">Line 30:</td> <td colspan="2" class="diff-lineno">Line 30:</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>==Solutions==</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>==Solutions==</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>Solutions for this assignment were discussed in [[Operating Systems 2014F Lecture 22|Lecture 22]].</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>Solutions for this assignment were discussed in [[Operating Systems 2014F Lecture 22|Lecture 22]].</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;"># Logical size is 268435456 bytes (as reported by ls -l). Physical size is 262144 blocks (as reported by ls -ls). By default ls assumes blocks are 1K in size; thus the physical space taken up by the file is 262144 * 1024 = 268439552 bytes. In other words, the physical size is 4096 bytes larger than the logical size. Note ext4 by default uses 4K blocks.</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;"># No - it consumes less space. The logical size stays the same, but now it only consumes 8798208 bytes. In other words the physical size is around 3.3% of the logical size! (Note mkfs.ext4 somehow inserted "holes" into the file.)</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;"># fsck or fsck.ext4 (fsck calls fsck.ext4 when it figures out the filesystem is ext4)</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;"># Anything previously in /mnt is now not available, and the files of the filesystem in foo are now available within /mnt.</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;"># /dev/loop0. This is a loopback block device. It allows a file such as foo (associated with the device) to be accessed as if it were a block device.</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;"></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;"># rsync -a -v /etc /mnt. Synchronize (in this case, copy) contents of /etc to /mnt. -a means archive (use recursion and grab almost everythin), -v is verbose.</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;"># Any files that were previously in /mnt before the mount command is now accessible. Any files that were in /mnt (i.e, in the foo filesystem) are not accessible.</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;"># conv=notrunc means that dd will not truncate the file after it is done writing - it leaves other data in the file intact.</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;"># error is: mount: you must specify the filesystem type</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;"># fsck?</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;"># Logical size is 1G. Physical size is 0.</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;"># The logical size stays the same. The physical size increases.</ins></div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19535&oldid=prev Soma at 20:18, 5 December 2014 2014-12-05T20:18:15Z

<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 20:18, 5 December 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l27">Line 27:</td> <td colspan="2" class="diff-lineno">Line 27:</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><li>[4] Write a program that prints out the last few lines of a file. The program should be efficient, in that it seeks to near the end of the file, reads in a block of data, and then goes backwards until it finds the requested number of lines; at this point, it should print out those lines from beginning to the end of the file. To invoke the program, one should type: mytail -n file, where n is the number of lines at the end of the file to print. Useful interfaces: stat(), lseek(), open(), read(), close().</li></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><li>[4] Write a program that prints out the last few lines of a file. The program should be efficient, in that it seeks to near the end of the file, reads in a block of data, and then goes backwards until it finds the requested number of lines; at this point, it should print out those lines from beginning to the end of the file. To invoke the program, one should type: mytail -n file, where n is the number of lines at the end of the file to print. Useful interfaces: stat(), lseek(), open(), read(), close().</li></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></ol></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></ol></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;">==Solutions==</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;">Solutions for this assignment were discussed in [[Operating Systems 2014F Lecture 22|Lecture 22]].</ins></div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19445&oldid=prev Soma: /* Part A */ 2014-11-07T20:39:14Z

<p><span dir="auto"><span class="autocomment">Part A</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 20:39, 7 November 2014</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># [1] Run <tt>umount /mnt</tt>. What files can you still access, and what have gone away?</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># [1] Run <tt>umount /mnt</tt>. What files can you still access, and what have gone away?</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># [1] Run <tt>dd if=/dev/zero of=foo conv=notrunc count=10 bs=512</tt>. How does the "conv=notrunc" change dd's behavior (versus the command in question 1)?</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># [1] Run <tt>dd if=/dev/zero of=foo conv=notrunc count=10 bs=512</tt>. How does the "conv=notrunc" change dd's behavior (versus the command in question 1)?</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># [1] Run <tt>mount foo /mnt</tt>. What error do you get?</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># [1] Run <tt><ins style="font-weight: bold; text-decoration: none;">sudo </ins>mount foo /mnt</tt>. What error do you get?</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># [1] What command can you run to make foo mountable again? What characteristic of the file system enables this command to work?</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># [1] What command can you run to make foo mountable again? What characteristic of the file system enables this command to work?</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># [1] Run the command <tt>truncate -s 1G bar</tt>. What is the logical size of bar, and how much space does it consume on disk? How does this compare with foo?</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># [1] Run the command <tt>truncate -s 1G bar</tt>. What is the logical size of bar, and how much space does it consume on disk? How does this compare with foo?</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># [1] How does the logical size of <del style="font-weight: bold; text-decoration: none;">foo </del>change when you create an ext4 filesystem in it? What about the space consumed on disk?</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># [1] How does the logical size of <ins style="font-weight: bold; text-decoration: none;">bar </ins>change when you create an ext4 filesystem in it? What about the space consumed on disk?</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>==Part B==</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>==Part B==</div></td></tr> </table>

Soma https://homeostasis.scs.carleton.ca/wiki/index.php?title=Operating_Systems_2014F:_Assignment_6&diff=19444&oldid=prev Soma: /* Part A */ 2014-11-06T16:18:44Z

<p><span dir="auto"><span class="autocomment">Part A</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 16:18, 6 November 2014</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l16">Line 16:</td> <td colspan="2" class="diff-lineno">Line 16:</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># [1] Run <tt>rsync -a -v /etc /mnt</tt>. What does this command do? Explain the arguments as well.</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># [1] Run <tt>rsync -a -v /etc /mnt</tt>. What does this command do? Explain the arguments as well.</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># [1] Run <tt>umount /mnt</tt>. What files can you still access, and what have gone away?</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># [1] Run <tt>umount /mnt</tt>. What files can you still access, and what have gone away?</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># [1] Run <tt>dd if=/dev/zero of=foo conv=notrunc count=10 bs=512</tt>. <del style="font-weight: bold; text-decoration: none;">What </del>does <del style="font-weight: bold; text-decoration: none;">this </del>command <del style="font-weight: bold; text-decoration: none;">do</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># [1] Run <tt>dd if=/dev/zero of=foo conv=notrunc count=10 bs=512</tt>. <ins style="font-weight: bold; text-decoration: none;">How </ins>does <ins style="font-weight: bold; text-decoration: none;">the "conv=notrunc" change dd's behavior (versus the </ins>command <ins style="font-weight: bold; text-decoration: none;">in question 1)</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># [1] Run <tt>mount foo /mnt</tt>. What error do you get?</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># [1] Run <tt>mount foo /mnt</tt>. What error do you get?</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># [1] What command can you run to make foo mountable again? What characteristic of the file system enables this command to work?</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># [1] What command can you run to make foo mountable again? What characteristic of the file system enables this command to work?</div></td></tr> </table>

Soma