Skip to main content

Programming is more difficult than people think...


Comments

Post a Comment

Popular posts from this blog

Developing a lightweight WebSocket library

Late in 2016, I began development on a lightweight, isomorphic WebSocket library for Node.js called ws-wrapper .  Today, this library is stable and has been successfully used in many production apps. Why?  What about socket.io ?  In my opinion, socket.io and its dependencies are way too heavy .  Now that the year is 2018, this couldn't be more true.  Modern browsers have native WebSocket support meaning that all of the transports built into the socket.io project are just dead weight.  On the other hand, ws-wrapper and its dependencies weigh about 3 KB when minified and gzipped.  Similarly, ws-wrapper consists of about 500 lines of code; whereas, socket.io consists of thousands of lines of code.  As Dijkstra once famously said: "Simplicity is prerequisite for reliability." ws-wrapper also provides a few more features out of the box.  The API exposes a two-way, Promise-based request/response interface.  That is, clients can request data from servers just as easily as se
Post a Comment
Read more

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.
Post a Comment
Read more

JavaScript Sticky Footer and Scroll Effect

This post talks about two different HTML/JavaScript effects: How to keep a page footer stuck at the bottom of the browser window. How to create a scrolling <div> without using a scroll bar OK. So... you have a website. You want a header stuck at the top of your page and the footer stuck at the bottom of your page. The stuff in the middle, you want to be able to scrollable. But, you don't want those ugly scrollbars to the right of your scrollable text. Maybe, instead, you'll have up arrows and down arrows above and below your <div>. When you mouseover the arrows, the text in the <div> will move up or down and create a scrolling effect. Suppose your page looks like this... <html> <head> <title>Test</title> </head> <body> <div style="position: relative; width: 700px; margin-left: auto; margin-right: auto;"> <div id="header">Header</div> <div id="scrollUp&q
1 comment
Read more