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Showing posts from July, 2012

Web Browsers You Should Support

As a web developer, generally speaking, you should consider supporting the following browsers (at the time of this writing): Chrome (latest) - the browser that sets the bar for the others; you should be using it and supporting it Internet Explorer 9+ - the browser that finally caught up with the times a bit; basically, a Chrome wannabe.  I still say that IE sucks... even if it really doesn't anymore.  Yes... I'm sour about IE8 and below. Internet Explorer 8 - the old, sad browser that we sadly still have to support for a while.  CSS 3 is not well-supported here, so we use projects like CSS3 PIE or whatever.  By the way... IE8 sucks.  I can't wait until this comes off of the list. Firefox (latest) - the browser that was once awesome and has sadly suffered recently because it's slower than Chrome... but hey, lots of people still use it. Safari (latest) - Watch out for Safari as more iPhones, iPads, Macs, and more overly-priced Apple products flood the market a

Computer Clocks Cause More Issues

Two nights ago, a leap second was added to system clocks running Linux, causing much-undesired havoc. On July 1st at 12:00 AM UTC, both of my Amazon EC2 instances fired an alarm indicating high CPU usage. I investigated to find that it was MySQL that was eating all of the CPU. I logged in and ran SHOW PROCESSLIST to find that no queries were running (these servers don't get hit much after business hours). I stopped MySQL, CPU utilization dropped back down to 1-3% (as normal). I restarted MySQL, and it started eating a lot of CPU again. Then, I restarted the server (shutdown -r now), and the problem went away. Both servers had the exact same problem (running Ubuntu 12.04 LTS). In my particular case, MySQL began eating CPU, even after being restarted.  It was a livelock. The only relevant item I saw in the syslog was: Jun 30 23:59:59 hostname kernel: [14152976.187987] Clock: inserting leap second 23:59:60 UTC Oh yeah... leap seconds.  Those are super important.