The first 70% of SQL is pretty straightforward but the remaining 30% can be pretty tricky. Working through this guide should improve your performance on data analyst interviews. It should also make you better at your current and future job positions. Personally, I find some of the SQL patterns found in this doc useful for ETLs powering reporting tools featuring trends over time.

This series explains concepts that are fundamental to deep learning and artificial neural networks for beginners. In addition to covering these concepts, we also show how to implement some of the concepts in code using Keras, a neural network API written in Python. This site also has a bunch of free courses on Deep Learning. You can check them out under Courses menu. The best is they are all free.

Time is always tricky. Timezone conversion, parsing from string, parse from Epoch, leap second etc. Y2K issue, 2038 issue. Why is time so hard to get right? This article tackle complexity of time: system time, hardware time, internal timers, time syncing.

Sometimes bugs have symptoms beyond belief. This is a collection of such stories from around the web. Some cool story such as a car won’t start when its owner buy vanilla ice cream. When you think out of the box, look at every data point, you will be able to solve the problem eventually

This is an experimental “book” about regular expressions. It is largely visual and example-based, as opposed to most regex resources I found while I was learning. I also attempted to choose test cases that highlight some common gotchas. I think it’ll be worth your time.

A TCP reset attack is executed using a single packet of data, no more than a few bytes in size. A spoofed TCP segment, crafted and sent by an attacker, tricks two victims into abandoning a TCP connection, interrupting possibly vital communications between them. The attack is believed to be a key component of China’s Great Firewall, used by the Chinese government to censor the internet inside China. Despite this weighty biography, understanding the attack doesn’t require deep prior knowledge of networking or TCP.

A great list of actionable items when you are being handled the keys to an AWS environment with absolutely no explanation of its contents, documentation, or training. This guide to help you filter through the mess, isolate the changes you need to make, and start to tame your environmens. Domain takeover via unclaimed resources is what many people will miss when inheriting an AWS account.

You know the kind of app when you hand draw a shape on screen, it automatically attempt to smooth out to the right shape. Want to know what is the algorithm behind them?

It reads like a sale pitch for Segment, but it’s pretty good. They need to forward analytic event to many providers such as google, mixpanel, saleforce .Queue isn’t a good option when the job is fan out data to third party. The queue which only has push/pop action may block entire queue when third party is down. Some very good design there to handle retry, avoid back pressure block the queue.

Not much on systemd but more focus on SystemTap, diagnostic tool for instrumenting and inspecting parts of Linux that traditional tools cannot reach. Among other things, SystemTap allows you to place probes in a kernel module that will fire when particular functions run. From there, you can query the function parameters or the return value and walk the stack or display a stack trace.

Explore how to secure and sandbox your applications with systemd. Though the article is for systemd, It’s general and available in Ubuntu/Debian as well. You can configured readonly directory for certain path, hide directories from processes etc

Challenges and Options for Validation and Debugging Distributed Systems.