The Linux Threads implementation which today is Linux's POSIX thread library is based on the principles outlined by the kernel developers at the time the code was written(1996). The basic assumption is that context switches among related processes a
A Practical Guide to Ubuntu Linux Ubuntu Linux 实战手册 183 7 The Shell 219 PART III Digging into Ubuntu Linux 249 8 Linux GUIs: X and GNOME 251 9 The Bourne Again Shell 275 10 Networking and the Internet 353 11 Programming the Bourne Again Shell 395 x
This document is completely, utterly out of date when it comes to descr iptions of the limitations of the current implementation. Everybody referring to this document to document shortcomings of NPTL is either a moron who hasn’t done her/his homewor
最近发现一个问题，ps命令输出里面进程状态为S+的含义，网上好多文章都说是表明进程“位于在后台进程组”。
例如下面这个ps命令输出说明：
D 不可中断 Uninterruptible sleep (usually IO)
R 正在运行，或在队列中的进程
S 处于休眠状态
T 停止或被追踪
Z 僵尸进程
W 进入内存交换（从内核2.6开始无效）
X 死掉的进程
< 高优先级
N 低优先级
L 有些页被锁进内存
s 包含子进程
+ 位于后台的进程组；
l 多线程，克
