{"id":3740,"date":"2012-11-13T20:04:12","date_gmt":"2012-11-14T01:04:12","guid":{"rendered":"http:\/\/blogs.n1zyy.com\/n1zyy\/?p=3740"},"modified":"2012-11-13T20:04:12","modified_gmt":"2012-11-14T01:04:12","slug":"the-curious-case-of-my-macs-clock","status":"publish","type":"post","link":"https:\/\/blogs.n1zyy.com\/n1zyy\/2012\/11\/13\/the-curious-case-of-my-macs-clock\/","title":{"rendered":"The Curious Case of My Mac&#8217;s Clock"},"content":{"rendered":"<p>When I traveled to Europe and back, I switched through timezones a lot. I went from Boston to London. When in London, Boston switched off of DST. Then I moved from London to Brno, forward another hour. Then back to London, then back to Boston.<\/p>\n<p>Not wanting to lug my heavy Thinkpad around, I brought my MacBook Air on the trip. (And was appropriately ostracized by coworkers for bringing a Mac to a meeting at a company best known for its Linux distribution.) And it did something that kind of intrigued me &#8212; it automatically adjusted to the local timezone.<\/p>\n<p>Now, this shouldn&#8217;t be possible. My clock is synchronized using NTP, which exchanges UTC time, deliberately ignorant of timezones or DST. And even if NTP did use local timezones (which would be a huge disaster), it still wouldn&#8217;t have worked, because I had hardcoded some local clocks.<\/p>\n<p>Investigating a bit, I found <a href=\"http:\/\/www.macosxtips.co.uk\/index_files\/automatically-set-time-zone-by-location.php\">this<\/a>. This is seemingly a new feature, and it uses the operating system&#8217;s location service to find your timezone. My computer doesn&#8217;t have an onboard GPS, of course, so it&#8217;s doing one of two things &#8212; GeoIP, and\/or looking up the access points I can see against a database.<\/p>\n<p>This is really neat, but it&#8217;s also pretty damned creepy. Here is what I see when I visit that setting:<\/p>\n<p><a href=\"http:\/\/blogs.n1zyy.com\/n1zyy\/files\/2012\/11\/Screen-Shot-2012-11-13-at-8.01.29-PM.png\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-3741\" title=\"Mac OS - Set time zone using current location\" src=\"http:\/\/blogs.n1zyy.com\/n1zyy\/files\/2012\/11\/Screen-Shot-2012-11-13-at-8.01.29-PM.png\" alt=\"\" width=\"782\" height=\"699\" \/><\/a>It knows exactly where I am.<\/p>\n<p>I&#8217;m willing to bet it knows exactly where the closest tinfoil hat shop is, too.<\/p>","protected":false},"excerpt":{"rendered":"<p>When I traveled to Europe and back, I switched through timezones a lot. I went from Boston to London. When in London, Boston switched off of DST. Then I moved from London to Brno, forward another hour. Then back to &hellip; <a href=\"https:\/\/blogs.n1zyy.com\/n1zyy\/2012\/11\/13\/the-curious-case-of-my-macs-clock\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,24],"tags":[],"class_list":["post-3740","post","type-post","status-publish","format-standard","hentry","category-computers","category-rants-raves"],"_links":{"self":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/posts\/3740","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/comments?post=3740"}],"version-history":[{"count":0,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/posts\/3740\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/media?parent=3740"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/categories?post=3740"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/tags?post=3740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}