1.Ubuntu
它的意思每一位Geek应该都知道，这是一个古非洲语单词，代表“人性”或者“我的存在是因为大家的存在”。
2.PCLinuxOS
PC + Linux + Operating System，用户界面很像Windows。
3.openSUSE
是Novell和AMD资助的SUSE社区项目，SUSE取德语单词首字母“Software- und System-Entwicklung” (软件和软件开发)。但也有人声称它是为了纪念计算机工程师 Konrad Zuse 。
4-Fedora
Fedora is a community Linux project sponsored by Red Hat. The name “fedora” is derived from the fedora that the shadowman is wearing in the Red Hat logo. (see below)
5-Mandriva
This Linux distro was the original Mandrake Linux distro, which was maintained by MandrakeSoft, however MandrakeSoft lost a legal battle against Hearst Corporation over the name “Mandrake”. MandrakeSoft later on bought Connectiva, the result of the fusion = Mandriva
6-Sabayon
Sabayon is a distro produced in Trentino, Italy and is named after an Italian dessert also called Sabayon. Sabayon (or Zabaglione) is made of egg yolks, sugar, and sweet liquor.
7-Debian
Debian was first introduced by Ian Murdock in 1998. The name itself is a portmanteau of his girlfriend (now wife) Debra and his name Ian.
8-Damn Small Linux
Damn Small Linux is a very small Linux distro with the size of only 50 MB. Hence the name. Like Duuuuh
号称是最小的光碟版迷你LINUX,不过麻雀虽小,五脏俱全,可以通过有线网卡、pppoe adsl拔号或无线网卡接入internet上网，也带有monkey web、ftp等服务器，还带有excel、pdf、MP3等软件。
9-MEPIS
According to the original creator of MEPIS, Warren Woodford, MEPIS orginally didn’t mean anything, he just misheard a friend on a bad Skype connection, and liked the name!
10-FreeBSD
FreeBSD is not exactly a Linux distro, it’ more like a sibling of Linux, and it ranked 11 on distrowatch. BSD is a Unix derivative developed by the University of Califrnia at Berkeley, BSD itself is an acronym for Berkeley Software Distribution. FreeBSD is the free branch of the Berkeley Distro.
linux并不是实时操作系统，把下面的代码运行一遍就能够理解了，代码有很详细的注释。
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <signal.h>
#include <string.h>
void * thr_fun(void *arg)
{
int policy, ret;
str ......
