adohe-zz

1. Distributed systems are different because they fail often. What sets distributed systems engineering apart is the probability of failure and, worse, the probability of partial failure. Networked systems fail more than systems that exist on only a single machine and that failures tend to be partial instead of total. Design for failure.

2. Writing robust distributed systems costs more than writing robust single-machine systems. There are failure conditions that are difficult to replicate on a single machine. Distributed systems tend to need actual, not simulated, distribution to flush out their bugs. Simulation is, of course, very useful.

3. Robust, open source distributed systems are much less common than robust, single-machine systems.

4. Coordination is very hard. Avoid coordination machines wherever possible. This is often describled as "horizontal scalability". The real trick of horizontal scalability is independence - being able to get data to machines such that communication and consensus between t

adohe-zz

package com.xqbase.java;

/**
 * LeetCode02 -- Add Two Numbers
 *
 * @author Tony He
 */
public class AddTwoNumbers {

    public static class ListNode {

adohe-zz

public class BoundedHashSet<T> {
  private final Set<T> set;
  private final Semaphore sem;

  public BoundedHashSet(int bound) {
    set = Collections.synchronizedSet(new HashSet<T>());
    sem = new Semphore(bound);
  }

  public boolean add(T o) throw InterruptedException {

adohe-zz

package com.xqbase.java;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.zip.GZIPInputStream;

public class CheckGZIPStream {

adohe-zz

curl http://nodejs.org/dist/<version>/node-<version>.tar.gz
tar zxvf node-<version>.tar.gz
cd node-<version>
./configure
make
[sudo] make install

adohe-zz

var http = require('http'),
    fs = require('fs'),
    parse = require('url').parse;

function upload(url, filePath, callback) {
  var urlObj = parse(url),
      path = urlObj.pathname + (urlObj.search || ''),
      options = {
        hostname: urlObj.hostname,
        path: path,

adohe-zz

var http = require('http'),
    parse = require('url').parse;

function requestUrl(url, callback) {
  var urlObj = parse(url),
      path = urlObj.pathname + (urlObj.search || ''),
      options = {
        hostname: urlObj.hostname,
        path: path,
        port: urlObj.port || 80,

adohe-zz

   in UNIX system, there are three special file descriptors,
they are stdin, stdout, stderr, and the corrsponding file
descriptors are 0, 1, 2, and they are store in the corrsponding
FILE struct.

adohe-zz

#include <stdio.h>
#include <stdlib.h>

int power(int m, int n);

int main() {
  int m, n;
  system("clear");

  printf("Enter two numbers:\n");

adohe-zz

package com.ado.java;

public class TestRef {

    public static void main(String[] args)
    {
        ValueObject vo1 = new ValueObject("A", 1);
        System.out.println("after vo1: " + vo1.getName()); //=A

        changeValue1(vo1);