<div class="xblock xblock-public_view xblock-public_view-vertical" data-runtime-class="LmsRuntime" data-init="VerticalStudentView" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="vertical" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@10fab2db5e65470d9b7161ccc09cc6b9">
<h2 class="hd hd-2 unit-title">An Introduction to Magnetic Data Storage</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a">
<div class="xblock xblock-public_view xblock-public_view-video xmodule_display xmodule_VideoBlock" data-runtime-class="LmsRuntime" data-init="XBlockToXModuleShim" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="video" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Video"}
</script>
<h3 class="hd hd-2">An Introduction to Magnetic Data Storage</h3>
<div
id="video_ff01cb665aeb40a59a253cfc6e593b6a"
class="video closed"
data-metadata='{"saveStateEnabled": false, "speed": null, "ytMetadataEndpoint": "", "transcriptAvailableTranslationsUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a/handler/transcript/available_translations", "captionDataDir": null, "completionEnabled": false, "poster": "https://mitx-edx-video-meta-storage.s3.amazonaws.com/media/video-images/365b4e20bcd146b7911d040c72285bfd.jpeg?AWSAccessKeyId=ASIA4QDFFSURUAQOWTZO&Expires=1725732771&x-amz-security-token=IQoJb3JpZ2luX2VjEAsaCXVzLWVhc3QtMSJHMEUCIGHcW9BaDPAfot2bk6Mqz7t0OMX3SX56dCiIiexhEtb9AiEAn8Z5SkZIa1bbVXhxx6OfmIbgr%2FTg7aJJgDAmAQt36jIquQUIMxADGgw4NTkyMDU2Mzc0MTEiDO2NGQYdEquOFyHSwCqWBQdwwcDCZLfCROPrIp90a8gYuTn%2BQIFMw77wKeKxW%2FIl8BS%2FdMMA6phkSAYlUdTdYBSZ0WF%2BL6MW7ExYoDpyThq7fQa4smk9zP64E2rUiLOqUtjJxCSlk8JduJeThBTGH%2FTkgWJ%2Bc5Y0qhFBfwVUeSGfW9QyAZW1H5YV6daGgL17390jOV1e2wUQ4KdnjOrN5y9FIHnnvyCb1L8oj2wGrnotAVq25iO628MkFrQsBZngiGqGUVgmJigRdR7d1HOS%2B1dCzax3DeGb03WFXFksTfmqk9DGkILIFAgeah0g%2Bs%2BsraCRa03YcbYrU92vbdtn5WG3BVYiVJ0q0CEJApEHxkSkxNftWXuELNfKU2JqnBFnlFuuU6iwp%2FgzuBdNb175WDTmACRwv%2FQZ4%2BbGEWa6WP7fnv7338U3VsELsxn413H73tXNDnXDNi3aD9L0yxwPqxEJE1%2FW87J3M9chXABX4Re4FLgJ4fTGWU99FuMj4cELJhcU6uuw3Mj4BlpkJTBQ3upAUh8yuQLqvGL9oHXdk0HM0vyqNLzrt%2BSefEYGIqDS%2Fti1w4jbLITZfWp6P3s9lsEV1MXVl%2F3xvYjCZo3eeQ854YmiYQfDYpHPatc4s5BMvEF%2FbgcQtqNStIR6hpluWS%2BbMX4pLeetb5Dg6H%2BGXz%2FH3KbjN5v5aWwxMNq4eYnuw74OaLqkZL3ODhrdcwBb7zXlySRGqNU9vzmWBMkGnVwzjAHlEJA5FoPLgmL%2F9ArBy1a14Mhc5jA%2B8USpqedcR59JI1uKSO42o%2B6yELneglXH5md3ryZqjGz0Xh1uEI%2BtnSIpbiGzBXyBDqGPAGQumRBnAOvVptdfb%2Buf1%2FhUABfCSp3Z%2B7NDEx7IFlqwXXlbpIpPo%2FKtMKqs8rYGOrEBd68XBDaoYhoDMchO4Lh2Oyxru%2FFQHXvLUy7IkYGxlD1NqYNxjttw%2FiAM%2F%2FxBtNU%2FlQOBv7pb4iAFqkvCScB9Of%2Fxu%2Flv%2BoqI8NcyoSZOdSkzKCODOn%2BgDt6EZ7dYdrPV49crkRto30%2BAHtN8uB1PNBNoPS00VWrNiQHszp%2FC7pm7%2BZe1voBWqNvnoaoVd40u%2B7ClQEJK6UVbhET0iIe%2FK%2BD27qVSUJw%2BvCGi8QJmlSmc&Signature=J%2BfFk9NOL62v8OcvGqFpU1tuoiQ%3D", "generalSpeed": 1.0, "transcriptLanguages": {"en": "English"}, "transcriptTranslationUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a/handler/transcript/translation/__lang__", "start": 0.0, "end": 0.0, "savedVideoPosition": 0.0, "lmsRootURL": "https://openlearninglibrary.mit.edu", "saveStateUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a/handler/xmodule_handler/save_user_state", "ytApiUrl": "https://www.youtube.com/iframe_api", "autoAdvance": false, "ytTestTimeout": 1500, "publishCompletionUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a/handler/publish_completion", "showCaptions": "true", "autohideHtml5": false, "streams": "1.00:fgCP8PGjsro", "prioritizeHls": false, "duration": 401.4, "transcriptLanguage": "en", "autoplay": false, "completionPercentage": 0.95, "recordedYoutubeIsAvailable": true, "sources": ["https://d2f1egay8yehza.cloudfront.net/MIT315XX/MIT315XXT115-V009500_DTH.mp4", "https://d2f1egay8yehza.cloudfront.net/MIT315XXT115-V009500/MIT315XXT115-V009500.m3u8"]}'
data-bumper-metadata='null'
data-autoadvance-enabled="False"
data-poster='null'
tabindex="-1"
>
<div class="focus_grabber first"></div>
<div class="tc-wrapper">
<div class="video-wrapper">
<span tabindex="0" class="spinner" aria-hidden="false" aria-label="Loading video player"></span>
<span tabindex="-1" class="btn-play fa fa-youtube-play fa-2x is-hidden" aria-hidden="true" aria-label="Play video"></span>
<div class="video-player-pre"></div>
<div class="video-player">
<div id="ff01cb665aeb40a59a253cfc6e593b6a"></div>
<h4 class="hd hd-4 video-error is-hidden">No playable video sources found.</h4>
<h4 class="hd hd-4 video-hls-error is-hidden">
Your browser does not support this video format. Try using a different browser.
</h4>
</div>
<div class="video-player-post"></div>
<div class="closed-captions"></div>
<div class="video-controls is-hidden">
<div>
<div class="vcr"><div class="vidtime">0:00 / 0:00</div></div>
<div class="secondary-controls"></div>
</div>
</div>
</div>
</div>
<div class="focus_grabber last"></div>
<h3 class="hd hd-4 downloads-heading sr" id="video-download-transcripts_ff01cb665aeb40a59a253cfc6e593b6a">Downloads and transcripts</h3>
<div class="wrapper-downloads" role="region" aria-labelledby="video-download-transcripts_ff01cb665aeb40a59a253cfc6e593b6a">
<div class="wrapper-download-transcripts">
<h4 class="hd hd-5">Transcripts</h4>
<ul class="list-download-transcripts">
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a/handler/transcript/download" data-value="srt">Download SubRip (.srt) file</a>
</li>
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ff01cb665aeb40a59a253cfc6e593b6a/handler/transcript/download" data-value="txt">Download Text (.txt) file</a>
</li>
</ul>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-runtime-class="LmsRuntime" data-init="VerticalStudentView" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="vertical" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@5e10556a38cb49259c14d48e3dc88e8b">
<h2 class="hd hd-2 unit-title">Longitudinal Magnetic Recording</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a">
<div class="xblock xblock-public_view xblock-public_view-video xmodule_display xmodule_VideoBlock" data-runtime-class="LmsRuntime" data-init="XBlockToXModuleShim" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="video" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Video"}
</script>
<h3 class="hd hd-2">Longitudinal Magnetic Recording</h3>
<div
id="video_d979ac2c5dcf43b2840ef2df047e312a"
class="video closed"
data-metadata='{"saveStateEnabled": false, "speed": null, "ytMetadataEndpoint": "", "transcriptAvailableTranslationsUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a/handler/transcript/available_translations", "captionDataDir": null, "completionEnabled": false, "poster": "https://mitx-edx-video-meta-storage.s3.amazonaws.com/media/video-images/84af4f7b69b9485ab08b4281bc10201f.jpeg?AWSAccessKeyId=ASIA4QDFFSURUAQOWTZO&Expires=1725732771&x-amz-security-token=IQoJb3JpZ2luX2VjEAsaCXVzLWVhc3QtMSJHMEUCIGHcW9BaDPAfot2bk6Mqz7t0OMX3SX56dCiIiexhEtb9AiEAn8Z5SkZIa1bbVXhxx6OfmIbgr%2FTg7aJJgDAmAQt36jIquQUIMxADGgw4NTkyMDU2Mzc0MTEiDO2NGQYdEquOFyHSwCqWBQdwwcDCZLfCROPrIp90a8gYuTn%2BQIFMw77wKeKxW%2FIl8BS%2FdMMA6phkSAYlUdTdYBSZ0WF%2BL6MW7ExYoDpyThq7fQa4smk9zP64E2rUiLOqUtjJxCSlk8JduJeThBTGH%2FTkgWJ%2Bc5Y0qhFBfwVUeSGfW9QyAZW1H5YV6daGgL17390jOV1e2wUQ4KdnjOrN5y9FIHnnvyCb1L8oj2wGrnotAVq25iO628MkFrQsBZngiGqGUVgmJigRdR7d1HOS%2B1dCzax3DeGb03WFXFksTfmqk9DGkILIFAgeah0g%2Bs%2BsraCRa03YcbYrU92vbdtn5WG3BVYiVJ0q0CEJApEHxkSkxNftWXuELNfKU2JqnBFnlFuuU6iwp%2FgzuBdNb175WDTmACRwv%2FQZ4%2BbGEWa6WP7fnv7338U3VsELsxn413H73tXNDnXDNi3aD9L0yxwPqxEJE1%2FW87J3M9chXABX4Re4FLgJ4fTGWU99FuMj4cELJhcU6uuw3Mj4BlpkJTBQ3upAUh8yuQLqvGL9oHXdk0HM0vyqNLzrt%2BSefEYGIqDS%2Fti1w4jbLITZfWp6P3s9lsEV1MXVl%2F3xvYjCZo3eeQ854YmiYQfDYpHPatc4s5BMvEF%2FbgcQtqNStIR6hpluWS%2BbMX4pLeetb5Dg6H%2BGXz%2FH3KbjN5v5aWwxMNq4eYnuw74OaLqkZL3ODhrdcwBb7zXlySRGqNU9vzmWBMkGnVwzjAHlEJA5FoPLgmL%2F9ArBy1a14Mhc5jA%2B8USpqedcR59JI1uKSO42o%2B6yELneglXH5md3ryZqjGz0Xh1uEI%2BtnSIpbiGzBXyBDqGPAGQumRBnAOvVptdfb%2Buf1%2FhUABfCSp3Z%2B7NDEx7IFlqwXXlbpIpPo%2FKtMKqs8rYGOrEBd68XBDaoYhoDMchO4Lh2Oyxru%2FFQHXvLUy7IkYGxlD1NqYNxjttw%2FiAM%2F%2FxBtNU%2FlQOBv7pb4iAFqkvCScB9Of%2Fxu%2Flv%2BoqI8NcyoSZOdSkzKCODOn%2BgDt6EZ7dYdrPV49crkRto30%2BAHtN8uB1PNBNoPS00VWrNiQHszp%2FC7pm7%2BZe1voBWqNvnoaoVd40u%2B7ClQEJK6UVbhET0iIe%2FK%2BD27qVSUJw%2BvCGi8QJmlSmc&Signature=rnjKbkwpKBn4Jhyx%2BK6iY8DdBaY%3D", "generalSpeed": 1.0, "transcriptLanguages": {"en": "English"}, "transcriptTranslationUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a/handler/transcript/translation/__lang__", "start": 0.0, "end": 0.0, "savedVideoPosition": 0.0, "lmsRootURL": "https://openlearninglibrary.mit.edu", "saveStateUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a/handler/xmodule_handler/save_user_state", "ytApiUrl": "https://www.youtube.com/iframe_api", "autoAdvance": false, "ytTestTimeout": 1500, "publishCompletionUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a/handler/publish_completion", "showCaptions": "true", "autohideHtml5": false, "streams": "1.00:6Bjgxle9nCs", "prioritizeHls": false, "duration": 462.77, "transcriptLanguage": "en", "autoplay": false, "completionPercentage": 0.95, "recordedYoutubeIsAvailable": true, "sources": ["https://d2f1egay8yehza.cloudfront.net/MIT315XX/MIT315XXT115-V009600_DTH.mp4", "https://d2f1egay8yehza.cloudfront.net/MIT315XXT115-V009600/MIT315XXT115-V009600.m3u8"]}'
data-bumper-metadata='null'
data-autoadvance-enabled="False"
data-poster='null'
tabindex="-1"
>
<div class="focus_grabber first"></div>
<div class="tc-wrapper">
<div class="video-wrapper">
<span tabindex="0" class="spinner" aria-hidden="false" aria-label="Loading video player"></span>
<span tabindex="-1" class="btn-play fa fa-youtube-play fa-2x is-hidden" aria-hidden="true" aria-label="Play video"></span>
<div class="video-player-pre"></div>
<div class="video-player">
<div id="d979ac2c5dcf43b2840ef2df047e312a"></div>
<h4 class="hd hd-4 video-error is-hidden">No playable video sources found.</h4>
<h4 class="hd hd-4 video-hls-error is-hidden">
Your browser does not support this video format. Try using a different browser.
</h4>
</div>
<div class="video-player-post"></div>
<div class="closed-captions"></div>
<div class="video-controls is-hidden">
<div>
<div class="vcr"><div class="vidtime">0:00 / 0:00</div></div>
<div class="secondary-controls"></div>
</div>
</div>
</div>
</div>
<div class="focus_grabber last"></div>
<h3 class="hd hd-4 downloads-heading sr" id="video-download-transcripts_d979ac2c5dcf43b2840ef2df047e312a">Downloads and transcripts</h3>
<div class="wrapper-downloads" role="region" aria-labelledby="video-download-transcripts_d979ac2c5dcf43b2840ef2df047e312a">
<div class="wrapper-download-transcripts">
<h4 class="hd hd-5">Transcripts</h4>
<ul class="list-download-transcripts">
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a/handler/transcript/download" data-value="srt">Download SubRip (.srt) file</a>
</li>
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@d979ac2c5dcf43b2840ef2df047e312a/handler/transcript/download" data-value="txt">Download Text (.txt) file</a>
</li>
</ul>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-runtime-class="LmsRuntime" data-init="VerticalStudentView" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="vertical" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@0c0a482803a9468eba2aab75e0bdb64e">
<h2 class="hd hd-2 unit-title">Perpendicular Magnetic Recording</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3">
<div class="xblock xblock-public_view xblock-public_view-video xmodule_display xmodule_VideoBlock" data-runtime-class="LmsRuntime" data-init="XBlockToXModuleShim" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="video" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Video"}
</script>
<h3 class="hd hd-2">Perpendicular Magnetic Recording</h3>
<div
id="video_bcf76dcf9f104893af3bb20c27c5d1b3"
class="video closed"
data-metadata='{"saveStateEnabled": false, "speed": null, "ytMetadataEndpoint": "", "transcriptAvailableTranslationsUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3/handler/transcript/available_translations", "captionDataDir": null, "completionEnabled": false, "poster": "https://mitx-edx-video-meta-storage.s3.amazonaws.com/media/video-images/74e2763b39f640628cce85a0922c30c2.jpeg?AWSAccessKeyId=ASIA4QDFFSURUAQOWTZO&Expires=1725732771&x-amz-security-token=IQoJb3JpZ2luX2VjEAsaCXVzLWVhc3QtMSJHMEUCIGHcW9BaDPAfot2bk6Mqz7t0OMX3SX56dCiIiexhEtb9AiEAn8Z5SkZIa1bbVXhxx6OfmIbgr%2FTg7aJJgDAmAQt36jIquQUIMxADGgw4NTkyMDU2Mzc0MTEiDO2NGQYdEquOFyHSwCqWBQdwwcDCZLfCROPrIp90a8gYuTn%2BQIFMw77wKeKxW%2FIl8BS%2FdMMA6phkSAYlUdTdYBSZ0WF%2BL6MW7ExYoDpyThq7fQa4smk9zP64E2rUiLOqUtjJxCSlk8JduJeThBTGH%2FTkgWJ%2Bc5Y0qhFBfwVUeSGfW9QyAZW1H5YV6daGgL17390jOV1e2wUQ4KdnjOrN5y9FIHnnvyCb1L8oj2wGrnotAVq25iO628MkFrQsBZngiGqGUVgmJigRdR7d1HOS%2B1dCzax3DeGb03WFXFksTfmqk9DGkILIFAgeah0g%2Bs%2BsraCRa03YcbYrU92vbdtn5WG3BVYiVJ0q0CEJApEHxkSkxNftWXuELNfKU2JqnBFnlFuuU6iwp%2FgzuBdNb175WDTmACRwv%2FQZ4%2BbGEWa6WP7fnv7338U3VsELsxn413H73tXNDnXDNi3aD9L0yxwPqxEJE1%2FW87J3M9chXABX4Re4FLgJ4fTGWU99FuMj4cELJhcU6uuw3Mj4BlpkJTBQ3upAUh8yuQLqvGL9oHXdk0HM0vyqNLzrt%2BSefEYGIqDS%2Fti1w4jbLITZfWp6P3s9lsEV1MXVl%2F3xvYjCZo3eeQ854YmiYQfDYpHPatc4s5BMvEF%2FbgcQtqNStIR6hpluWS%2BbMX4pLeetb5Dg6H%2BGXz%2FH3KbjN5v5aWwxMNq4eYnuw74OaLqkZL3ODhrdcwBb7zXlySRGqNU9vzmWBMkGnVwzjAHlEJA5FoPLgmL%2F9ArBy1a14Mhc5jA%2B8USpqedcR59JI1uKSO42o%2B6yELneglXH5md3ryZqjGz0Xh1uEI%2BtnSIpbiGzBXyBDqGPAGQumRBnAOvVptdfb%2Buf1%2FhUABfCSp3Z%2B7NDEx7IFlqwXXlbpIpPo%2FKtMKqs8rYGOrEBd68XBDaoYhoDMchO4Lh2Oyxru%2FFQHXvLUy7IkYGxlD1NqYNxjttw%2FiAM%2F%2FxBtNU%2FlQOBv7pb4iAFqkvCScB9Of%2Fxu%2Flv%2BoqI8NcyoSZOdSkzKCODOn%2BgDt6EZ7dYdrPV49crkRto30%2BAHtN8uB1PNBNoPS00VWrNiQHszp%2FC7pm7%2BZe1voBWqNvnoaoVd40u%2B7ClQEJK6UVbhET0iIe%2FK%2BD27qVSUJw%2BvCGi8QJmlSmc&Signature=sJ0ZIibcFyP0mShQPihNch8VWBQ%3D", "generalSpeed": 1.0, "transcriptLanguages": {"en": "English"}, "transcriptTranslationUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3/handler/transcript/translation/__lang__", "start": 0.0, "end": 0.0, "savedVideoPosition": 0.0, "lmsRootURL": "https://openlearninglibrary.mit.edu", "saveStateUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3/handler/xmodule_handler/save_user_state", "ytApiUrl": "https://www.youtube.com/iframe_api", "autoAdvance": false, "ytTestTimeout": 1500, "publishCompletionUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3/handler/publish_completion", "showCaptions": "true", "autohideHtml5": false, "streams": "1.00:7Kpe02Qe4R8", "prioritizeHls": false, "duration": 262.9, "transcriptLanguage": "en", "autoplay": false, "completionPercentage": 0.95, "recordedYoutubeIsAvailable": true, "sources": ["https://d2f1egay8yehza.cloudfront.net/MIT315XX/MIT315XXT115-V009700_DTH.mp4", "https://d2f1egay8yehza.cloudfront.net/MIT315XXT115-V009700/MIT315XXT115-V009700.m3u8"]}'
data-bumper-metadata='null'
data-autoadvance-enabled="False"
data-poster='null'
tabindex="-1"
>
<div class="focus_grabber first"></div>
<div class="tc-wrapper">
<div class="video-wrapper">
<span tabindex="0" class="spinner" aria-hidden="false" aria-label="Loading video player"></span>
<span tabindex="-1" class="btn-play fa fa-youtube-play fa-2x is-hidden" aria-hidden="true" aria-label="Play video"></span>
<div class="video-player-pre"></div>
<div class="video-player">
<div id="bcf76dcf9f104893af3bb20c27c5d1b3"></div>
<h4 class="hd hd-4 video-error is-hidden">No playable video sources found.</h4>
<h4 class="hd hd-4 video-hls-error is-hidden">
Your browser does not support this video format. Try using a different browser.
</h4>
</div>
<div class="video-player-post"></div>
<div class="closed-captions"></div>
<div class="video-controls is-hidden">
<div>
<div class="vcr"><div class="vidtime">0:00 / 0:00</div></div>
<div class="secondary-controls"></div>
</div>
</div>
</div>
</div>
<div class="focus_grabber last"></div>
<h3 class="hd hd-4 downloads-heading sr" id="video-download-transcripts_bcf76dcf9f104893af3bb20c27c5d1b3">Downloads and transcripts</h3>
<div class="wrapper-downloads" role="region" aria-labelledby="video-download-transcripts_bcf76dcf9f104893af3bb20c27c5d1b3">
<div class="wrapper-download-transcripts">
<h4 class="hd hd-5">Transcripts</h4>
<ul class="list-download-transcripts">
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3/handler/transcript/download" data-value="srt">Download SubRip (.srt) file</a>
</li>
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@bcf76dcf9f104893af3bb20c27c5d1b3/handler/transcript/download" data-value="txt">Download Text (.txt) file</a>
</li>
</ul>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-runtime-class="LmsRuntime" data-init="VerticalStudentView" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="vertical" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@11edbad084a3435f8eefa637cfbc86be">
<h2 class="hd hd-2 unit-title">Magnetic Recording Media</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d">
<div class="xblock xblock-public_view xblock-public_view-video xmodule_display xmodule_VideoBlock" data-runtime-class="LmsRuntime" data-init="XBlockToXModuleShim" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="video" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Video"}
</script>
<h3 class="hd hd-2">Magnetic Recording Media</h3>
<div
id="video_181469d26fd6441984c08fa21fa8f64d"
class="video closed"
data-metadata='{"saveStateEnabled": false, "speed": null, "ytMetadataEndpoint": "", "transcriptAvailableTranslationsUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d/handler/transcript/available_translations", "captionDataDir": null, "completionEnabled": false, "poster": "https://mitx-edx-video-meta-storage.s3.amazonaws.com/media/video-images/096bb71adb83417092daf5ac6deb7a89.jpeg?AWSAccessKeyId=ASIA4QDFFSURUAQOWTZO&Expires=1725732773&x-amz-security-token=IQoJb3JpZ2luX2VjEAsaCXVzLWVhc3QtMSJHMEUCIGHcW9BaDPAfot2bk6Mqz7t0OMX3SX56dCiIiexhEtb9AiEAn8Z5SkZIa1bbVXhxx6OfmIbgr%2FTg7aJJgDAmAQt36jIquQUIMxADGgw4NTkyMDU2Mzc0MTEiDO2NGQYdEquOFyHSwCqWBQdwwcDCZLfCROPrIp90a8gYuTn%2BQIFMw77wKeKxW%2FIl8BS%2FdMMA6phkSAYlUdTdYBSZ0WF%2BL6MW7ExYoDpyThq7fQa4smk9zP64E2rUiLOqUtjJxCSlk8JduJeThBTGH%2FTkgWJ%2Bc5Y0qhFBfwVUeSGfW9QyAZW1H5YV6daGgL17390jOV1e2wUQ4KdnjOrN5y9FIHnnvyCb1L8oj2wGrnotAVq25iO628MkFrQsBZngiGqGUVgmJigRdR7d1HOS%2B1dCzax3DeGb03WFXFksTfmqk9DGkILIFAgeah0g%2Bs%2BsraCRa03YcbYrU92vbdtn5WG3BVYiVJ0q0CEJApEHxkSkxNftWXuELNfKU2JqnBFnlFuuU6iwp%2FgzuBdNb175WDTmACRwv%2FQZ4%2BbGEWa6WP7fnv7338U3VsELsxn413H73tXNDnXDNi3aD9L0yxwPqxEJE1%2FW87J3M9chXABX4Re4FLgJ4fTGWU99FuMj4cELJhcU6uuw3Mj4BlpkJTBQ3upAUh8yuQLqvGL9oHXdk0HM0vyqNLzrt%2BSefEYGIqDS%2Fti1w4jbLITZfWp6P3s9lsEV1MXVl%2F3xvYjCZo3eeQ854YmiYQfDYpHPatc4s5BMvEF%2FbgcQtqNStIR6hpluWS%2BbMX4pLeetb5Dg6H%2BGXz%2FH3KbjN5v5aWwxMNq4eYnuw74OaLqkZL3ODhrdcwBb7zXlySRGqNU9vzmWBMkGnVwzjAHlEJA5FoPLgmL%2F9ArBy1a14Mhc5jA%2B8USpqedcR59JI1uKSO42o%2B6yELneglXH5md3ryZqjGz0Xh1uEI%2BtnSIpbiGzBXyBDqGPAGQumRBnAOvVptdfb%2Buf1%2FhUABfCSp3Z%2B7NDEx7IFlqwXXlbpIpPo%2FKtMKqs8rYGOrEBd68XBDaoYhoDMchO4Lh2Oyxru%2FFQHXvLUy7IkYGxlD1NqYNxjttw%2FiAM%2F%2FxBtNU%2FlQOBv7pb4iAFqkvCScB9Of%2Fxu%2Flv%2BoqI8NcyoSZOdSkzKCODOn%2BgDt6EZ7dYdrPV49crkRto30%2BAHtN8uB1PNBNoPS00VWrNiQHszp%2FC7pm7%2BZe1voBWqNvnoaoVd40u%2B7ClQEJK6UVbhET0iIe%2FK%2BD27qVSUJw%2BvCGi8QJmlSmc&Signature=u2AN%2FiAHNxLvmiJyiahNwKhQCvI%3D", "generalSpeed": 1.0, "transcriptLanguages": {"en": "English"}, "transcriptTranslationUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d/handler/transcript/translation/__lang__", "start": 0.0, "end": 0.0, "savedVideoPosition": 0.0, "lmsRootURL": "https://openlearninglibrary.mit.edu", "saveStateUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d/handler/xmodule_handler/save_user_state", "ytApiUrl": "https://www.youtube.com/iframe_api", "autoAdvance": false, "ytTestTimeout": 1500, "publishCompletionUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d/handler/publish_completion", "showCaptions": "true", "autohideHtml5": false, "streams": "1.00:ReQFkPKEWrg", "prioritizeHls": false, "duration": 206.01, "transcriptLanguage": "en", "autoplay": false, "completionPercentage": 0.95, "recordedYoutubeIsAvailable": true, "sources": ["https://d2f1egay8yehza.cloudfront.net/MIT315XX/MIT315XXT115-V008700_DTH.mp4", "https://d2f1egay8yehza.cloudfront.net/MIT315XXT115-V008700/MIT315XXT115-V008700.m3u8"]}'
data-bumper-metadata='null'
data-autoadvance-enabled="False"
data-poster='null'
tabindex="-1"
>
<div class="focus_grabber first"></div>
<div class="tc-wrapper">
<div class="video-wrapper">
<span tabindex="0" class="spinner" aria-hidden="false" aria-label="Loading video player"></span>
<span tabindex="-1" class="btn-play fa fa-youtube-play fa-2x is-hidden" aria-hidden="true" aria-label="Play video"></span>
<div class="video-player-pre"></div>
<div class="video-player">
<div id="181469d26fd6441984c08fa21fa8f64d"></div>
<h4 class="hd hd-4 video-error is-hidden">No playable video sources found.</h4>
<h4 class="hd hd-4 video-hls-error is-hidden">
Your browser does not support this video format. Try using a different browser.
</h4>
</div>
<div class="video-player-post"></div>
<div class="closed-captions"></div>
<div class="video-controls is-hidden">
<div>
<div class="vcr"><div class="vidtime">0:00 / 0:00</div></div>
<div class="secondary-controls"></div>
</div>
</div>
</div>
</div>
<div class="focus_grabber last"></div>
<h3 class="hd hd-4 downloads-heading sr" id="video-download-transcripts_181469d26fd6441984c08fa21fa8f64d">Downloads and transcripts</h3>
<div class="wrapper-downloads" role="region" aria-labelledby="video-download-transcripts_181469d26fd6441984c08fa21fa8f64d">
<div class="wrapper-download-transcripts">
<h4 class="hd hd-5">Transcripts</h4>
<ul class="list-download-transcripts">
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d/handler/transcript/download" data-value="srt">Download SubRip (.srt) file</a>
</li>
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@181469d26fd6441984c08fa21fa8f64d/handler/transcript/download" data-value="txt">Download Text (.txt) file</a>
</li>
</ul>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-runtime-class="LmsRuntime" data-init="VerticalStudentView" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="vertical" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@762f318d95e94d79ba72ac0b7027526a">
<h2 class="hd hd-2 unit-title">Hard Drives: Write Process</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c">
<div class="xblock xblock-public_view xblock-public_view-video xmodule_display xmodule_VideoBlock" data-runtime-class="LmsRuntime" data-init="XBlockToXModuleShim" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="video" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Video"}
</script>
<h3 class="hd hd-2">Hard Drives: Write Process</h3>
<div
id="video_ca493751c4a24d5bb10a498bf73a9d9c"
class="video closed"
data-metadata='{"saveStateEnabled": false, "speed": null, "ytMetadataEndpoint": "", "transcriptAvailableTranslationsUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c/handler/transcript/available_translations", "captionDataDir": null, "completionEnabled": false, "poster": "https://mitx-edx-video-meta-storage.s3.amazonaws.com/media/video-images/0059f6297a784a7da8cfec217cbfbc05.jpeg?AWSAccessKeyId=ASIA4QDFFSURUAQOWTZO&Expires=1725732773&x-amz-security-token=IQoJb3JpZ2luX2VjEAsaCXVzLWVhc3QtMSJHMEUCIGHcW9BaDPAfot2bk6Mqz7t0OMX3SX56dCiIiexhEtb9AiEAn8Z5SkZIa1bbVXhxx6OfmIbgr%2FTg7aJJgDAmAQt36jIquQUIMxADGgw4NTkyMDU2Mzc0MTEiDO2NGQYdEquOFyHSwCqWBQdwwcDCZLfCROPrIp90a8gYuTn%2BQIFMw77wKeKxW%2FIl8BS%2FdMMA6phkSAYlUdTdYBSZ0WF%2BL6MW7ExYoDpyThq7fQa4smk9zP64E2rUiLOqUtjJxCSlk8JduJeThBTGH%2FTkgWJ%2Bc5Y0qhFBfwVUeSGfW9QyAZW1H5YV6daGgL17390jOV1e2wUQ4KdnjOrN5y9FIHnnvyCb1L8oj2wGrnotAVq25iO628MkFrQsBZngiGqGUVgmJigRdR7d1HOS%2B1dCzax3DeGb03WFXFksTfmqk9DGkILIFAgeah0g%2Bs%2BsraCRa03YcbYrU92vbdtn5WG3BVYiVJ0q0CEJApEHxkSkxNftWXuELNfKU2JqnBFnlFuuU6iwp%2FgzuBdNb175WDTmACRwv%2FQZ4%2BbGEWa6WP7fnv7338U3VsELsxn413H73tXNDnXDNi3aD9L0yxwPqxEJE1%2FW87J3M9chXABX4Re4FLgJ4fTGWU99FuMj4cELJhcU6uuw3Mj4BlpkJTBQ3upAUh8yuQLqvGL9oHXdk0HM0vyqNLzrt%2BSefEYGIqDS%2Fti1w4jbLITZfWp6P3s9lsEV1MXVl%2F3xvYjCZo3eeQ854YmiYQfDYpHPatc4s5BMvEF%2FbgcQtqNStIR6hpluWS%2BbMX4pLeetb5Dg6H%2BGXz%2FH3KbjN5v5aWwxMNq4eYnuw74OaLqkZL3ODhrdcwBb7zXlySRGqNU9vzmWBMkGnVwzjAHlEJA5FoPLgmL%2F9ArBy1a14Mhc5jA%2B8USpqedcR59JI1uKSO42o%2B6yELneglXH5md3ryZqjGz0Xh1uEI%2BtnSIpbiGzBXyBDqGPAGQumRBnAOvVptdfb%2Buf1%2FhUABfCSp3Z%2B7NDEx7IFlqwXXlbpIpPo%2FKtMKqs8rYGOrEBd68XBDaoYhoDMchO4Lh2Oyxru%2FFQHXvLUy7IkYGxlD1NqYNxjttw%2FiAM%2F%2FxBtNU%2FlQOBv7pb4iAFqkvCScB9Of%2Fxu%2Flv%2BoqI8NcyoSZOdSkzKCODOn%2BgDt6EZ7dYdrPV49crkRto30%2BAHtN8uB1PNBNoPS00VWrNiQHszp%2FC7pm7%2BZe1voBWqNvnoaoVd40u%2B7ClQEJK6UVbhET0iIe%2FK%2BD27qVSUJw%2BvCGi8QJmlSmc&Signature=z7650O%2FiOWnSr4BYN73HquxW7Pg%3D", "generalSpeed": 1.0, "transcriptLanguages": {"en": "English"}, "transcriptTranslationUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c/handler/transcript/translation/__lang__", "start": 0.0, "end": 0.0, "savedVideoPosition": 0.0, "lmsRootURL": "https://openlearninglibrary.mit.edu", "saveStateUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c/handler/xmodule_handler/save_user_state", "ytApiUrl": "https://www.youtube.com/iframe_api", "autoAdvance": false, "ytTestTimeout": 1500, "publishCompletionUrl": "/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c/handler/publish_completion", "showCaptions": "true", "autohideHtml5": false, "streams": "1.00:-q0C9efTB1s", "prioritizeHls": false, "duration": 386.53, "transcriptLanguage": "en", "autoplay": false, "completionPercentage": 0.95, "recordedYoutubeIsAvailable": true, "sources": ["https://d2f1egay8yehza.cloudfront.net/MIT315XX/MIT315XXT115-V010300_DTH.mp4", "https://d2f1egay8yehza.cloudfront.net/MIT315XXT115-V010300/MIT315XXT115-V010300.m3u8"]}'
data-bumper-metadata='null'
data-autoadvance-enabled="False"
data-poster='null'
tabindex="-1"
>
<div class="focus_grabber first"></div>
<div class="tc-wrapper">
<div class="video-wrapper">
<span tabindex="0" class="spinner" aria-hidden="false" aria-label="Loading video player"></span>
<span tabindex="-1" class="btn-play fa fa-youtube-play fa-2x is-hidden" aria-hidden="true" aria-label="Play video"></span>
<div class="video-player-pre"></div>
<div class="video-player">
<div id="ca493751c4a24d5bb10a498bf73a9d9c"></div>
<h4 class="hd hd-4 video-error is-hidden">No playable video sources found.</h4>
<h4 class="hd hd-4 video-hls-error is-hidden">
Your browser does not support this video format. Try using a different browser.
</h4>
</div>
<div class="video-player-post"></div>
<div class="closed-captions"></div>
<div class="video-controls is-hidden">
<div>
<div class="vcr"><div class="vidtime">0:00 / 0:00</div></div>
<div class="secondary-controls"></div>
</div>
</div>
</div>
</div>
<div class="focus_grabber last"></div>
<h3 class="hd hd-4 downloads-heading sr" id="video-download-transcripts_ca493751c4a24d5bb10a498bf73a9d9c">Downloads and transcripts</h3>
<div class="wrapper-downloads" role="region" aria-labelledby="video-download-transcripts_ca493751c4a24d5bb10a498bf73a9d9c">
<div class="wrapper-download-transcripts">
<h4 class="hd hd-5">Transcripts</h4>
<ul class="list-download-transcripts">
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c/handler/transcript/download" data-value="srt">Download SubRip (.srt) file</a>
</li>
<li class="transcript-option">
<a class="btn btn-link" href="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@video+block@ca493751c4a24d5bb10a498bf73a9d9c/handler/transcript/download" data-value="txt">Download Text (.txt) file</a>
</li>
</ul>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="xblock xblock-public_view xblock-public_view-vertical" data-runtime-class="LmsRuntime" data-init="VerticalStudentView" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="False" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="vertical" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@vertical+block@14572ad9f97c4665b26ee3c2160087e6">
<h2 class="hd hd-2 unit-title">In-Lecture Question 9.3</h2>
<div class="vert-mod">
<div class="vert vert-0" data-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@8296dd2067034fa2bc5c109273ac6439">
<div class="xblock xblock-public_view xblock-public_view-problem xmodule_display xmodule_ProblemBlock" data-runtime-class="LmsRuntime" data-init="XBlockToXModuleShim" data-graded="False" data-course-id="course-v1:MITx+3.15.3x+2T2017" data-has-score="True" data-request-token="187b15326d4411ef8ea20e199eb5def5" data-runtime-version="1" data-block-type="problem" data-usage-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@8296dd2067034fa2bc5c109273ac6439">
<script type="json/xblock-args" class="xblock-json-init-args">
{"xmodule-type": "Problem"}
</script>
<div id="problem_8296dd2067034fa2bc5c109273ac6439" class="problems-wrapper" role="group"
aria-labelledby="8296dd2067034fa2bc5c109273ac6439-problem-title"
data-problem-id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@8296dd2067034fa2bc5c109273ac6439" data-url="/courses/course-v1:MITx+3.15.3x+2T2017/xblock/block-v1:MITx+3.15.3x+2T2017+type@problem+block@8296dd2067034fa2bc5c109273ac6439/handler/xmodule_handler"
data-problem-score="0"
data-problem-total-possible="0"
data-attempts-used="0"
data-content="
<h3 class="hd hd-3 problem-header" id="8296dd2067034fa2bc5c109273ac6439-problem-title" aria-describedby="block-v1:MITx+3.15.3x+2T2017+type@problem+block@8296dd2067034fa2bc5c109273ac6439-problem-progress" tabindex="-1">
In-Lecture Question 9.3
</h3>
<div class="problem-progress" id="block-v1:MITx+3.15.3x+2T2017+type@problem+block@8296dd2067034fa2bc5c109273ac6439-problem-progress"></div>
<div class="problem">
<div>
<span id="anchor_change_my_id_for_each_one_on_the_page"/>
<script type="text/javascript">
/* The object here is to replace the single line input with a textarea */
(function() {
var elem = $("#anchor_change_my_id_for_each_one_on_the_page")
.closest("div.problem")
.find(":text");
/* There's CSS in the LMS that controls the height, so we have to override here */
var textarea = $('<textarea style="height:150px" rows="20" cols="70"/>');
console.log(elem);
console.log(textarea);
//This is just a way to do an iterator in JS
for (attrib in {'id':null, 'name':null}) {
textarea.attr(attrib, elem.attr(attrib));
}
/* copy over the submitted value */
textarea.val(elem.val())
elem.replaceWith(textarea);
})();
</script>
<p>Several types of magnetic devices, including transformers, electromagnets, and hard disk write heads, consist of a current-carrying coil wrapped around a magnetic core (or pole piece). </p>
<p>What is the purpose of the magnetic core? </p>
<div class="wrapper-problem-response" tabindex="-1" aria-label="Question 1" role="group"><div id="inputtype_8296dd2067034fa2bc5c109273ac6439_2_1" class=" capa_inputtype textline">
<div class="unanswered ">
<input type="text" name="input_8296dd2067034fa2bc5c109273ac6439_2_1" id="input_8296dd2067034fa2bc5c109273ac6439_2_1" aria-describedby="status_8296dd2067034fa2bc5c109273ac6439_2_1" value=""/>
<span class="trailing_text" id="trailing_text_8296dd2067034fa2bc5c109273ac6439_2_1"/>
<span class="status unanswered" id="status_8296dd2067034fa2bc5c109273ac6439_2_1" data-tooltip="Not yet answered.">
<span class="sr">unanswered</span><span class="status-icon" aria-hidden="true"/>
</span>
<p id="answer_8296dd2067034fa2bc5c109273ac6439_2_1" class="answer"/>
</div>
</div></div>
<div class="solution-span">
<span id="solution_8296dd2067034fa2bc5c109273ac6439_solution_1"/>
</div></div>
<div class="action">
<input type="hidden" name="problem_id" value="In-Lecture Question 9.3" />
<div class="submit-attempt-container">
<button type="button" class="submit btn-brand" data-submitting="Submitting" data-value="Submit" data-should-enable-submit-button="True" aria-describedby="submission_feedback_8296dd2067034fa2bc5c109273ac6439" >
<span class="submit-label">Submit</span>
</button>
<div class="submission-feedback" id="submission_feedback_8296dd2067034fa2bc5c109273ac6439">
<span class="sr">Some problems have options such as save, reset, hints, or show answer. These options follow the Submit button.</span>
</div>
</div>
<div class="problem-action-buttons-wrapper">
</div>
</div>
<div class="notification warning notification-gentle-alert
is-hidden"
tabindex="-1">
<span class="icon fa fa-exclamation-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="8296dd2067034fa2bc5c109273ac6439-problem-title">
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification warning notification-save
is-hidden"
tabindex="-1">
<span class="icon fa fa-save" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="8296dd2067034fa2bc5c109273ac6439-problem-title">None
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
<div class="notification general notification-show-answer
is-hidden"
tabindex="-1">
<span class="icon fa fa-info-circle" aria-hidden="true"></span>
<span class="notification-message" aria-describedby="8296dd2067034fa2bc5c109273ac6439-problem-title">Answers are displayed within the problem
</span>
<div class="notification-btn-wrapper">
<button type="button" class="btn btn-default btn-small notification-btn review-btn sr">Review</button>
</div>
</div>
</div>
"
data-graded="False">
<p class="loading-spinner">
<i class="fa fa-spinner fa-pulse fa-2x fa-fw"></i>
<span class="sr">Loading…</span>
</p>
</div>
</div>
</div>
</div>
</div>
© All Rights Reserved