Fei He droxer

Setting up and installing rbenv, ruby-build, rubies, rbenv-gemset, and bundler

This guide enables you to install (ruby-build) and use (rbenv) multiple versions of ruby, isolate project gems (gemsets and/or bundler), and automatically use appropriate combinations of rubies and gems.

TL;DR Demo

# Ensure system is in ship-shape.

aptitude install git zsh libssl-dev zlib1g-dev libreadline-dev libyaml-dev

	import javax.net.ssl.SSLParameters;
	import javax.net.ssl.SSLSocket;
	import javax.net.ssl.SSLSocketFactory;
	import java.io.*;

	/** Establish a SSL connection to a host and port, writes a byte and
	* prints the response. See
	* http://confluence.atlassian.com/display/JIRA/Connecting+to+SSL+services
	*/
	public class SSLPoke {

	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns
	Compress 1K bytes with Zippy 3,000 ns // 3微秒
	Send 2K bytes over 1 Gbps network 20,000 ns // 20微秒
	Read 1 MB sequentially from memory 250,000 ns // 0.25毫秒
	Round trip within same datacenter 500,000 ns // 0.5毫秒
	Disk seek 10,000,000 ns // 10毫秒

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

	public class BigPipeServlet extends HttpServlet {

	private static ExecutorService executor = Executors.newFixedThreadPool(500, new ThreadFactory() {
	public Thread newThread(Runnable r) {
	Thread t = new Thread(r);
	t.setName("Service Thread "+ t.getId());
	t.setDaemon(true);
	return t;
	}
	});

	# to generate your dhparam.pem file, run in the terminal
	openssl dhparam -out /etc/nginx/ssl/dhparam.pem 2048