对Linux系统正在运行的进程有些疑惑， 便用pstree命令查看。 然后在网上查找资料， 对部分进程做出一些浅解。

如下：

init-+-NetworkManager-+-dhclient	// network management daemon. It attemps to keep an active network connection 
					// available at all times.
     |                `-{NetworkManager}
     |-acpid //Advanced Configuration and Power Interface.	新型电源管理标准.
     |-atd	// run jobs queued for later execution.
     |-avahi-daemon---avahi-deemon	// The daemon registers local IP addresses and static services using mDNS/DNS-SD and
					// provides tow IPC APIs for local programs to make use of the mDNS record cache the
					// avahi-daemon maintains.
     |-bonobo-activati---{bonobo-activat}	// bonobo-activation is responsible on GNOME 2.x systems for the activation
						// of CORBA(Common Object Request Broker Architecuture, 公共对象请求代理体系结构
						// ) objects.
     |-chrome-+-3*[chrome]
     |        |-chrome---4*[{chrome}]
     |        `-23*[{chrome}]
     |-chrome---2*[chrome---2*[{chrome}]]
     |-clock-applet	// alarm clock for your notification area.
			// alarm-clock-applet is an applet providing alarm clock functionality which lives within the
			// notification area.
     |-console-kit-dae---63*[{console-kit-da}]	// ConsoleKit is a framework for keeping track of the various users,
						// sessions, and seats present on a system. It provides a mechanism
						// for software to react to changes of any of these items or of any
						// the metadata associated with them.
     |-cron	// cron守护进程执行预定的命令，它会在预定的时间执行预定的命令或脚本.
     |-cupsd	// common unix printing system daemon.
     |-2*[dbus-daemon]	// Message bus daemon.
			// D-Bus is first a library that provides one-to-one commnication between any two applications;
			// dbus-daemon is an application that uses this library to implement a message bus daemon.
			// Multiple programs connect to the message bus daemon and can exchange messages with one another.
     |-dbus-launch	// Utility to start a message bus from a shell script.
     |-gconfd-2		//1) it's basically a "registry" for gnome apps.   -- ?
			//2) This daemon's primary purpose is to notify applications when a configuration value has changed. --?
     |-gdm-binary-+-gdm-simple-slav-+-Xorg	// GDM is the GNOME Display Manager, a program used for login
						// session management. GDM is a wrapper script that launching gdb-binary and
						// passes along any option.
							// gdm-binary forks an Xserver and a slave process. The main
							// gdm-binary process then listens to XDMCP requests from remote
							// displays, if so configured, and monitors the local display sessions.
								// Xorg 是 X11 窗口系统的一个开源实现.
     |            |                 |-gdm-session-wor-+-gnome-session-+-compiz-+-sh---gtk-window-deco
     					// The gnome-session program starts up the GNOME desktop environment.
						// Compiz 是第一个由OpenGL驱动的运行于 X Window System 上的混合窗口管理器。
						// Compiz的混合渲染能力使其可以在窗口管理过程中实现多种视觉效果，比如在
						// 矩形虚拟桌面上的窗口最小化.
     |            |                 |                 |               |        `-sh---gnome-terminal-+-2*[bash]
     |            |                 |                 |               |                              |-bash---pstree
     |            |                 |                 |               |                              |-gnome-pty-helpe
     													// Help setuid application.
     |            |                 |                 |               |                              `-{gnome-terminal}
     |            |                 |                 |               |-evolution-alarm---{evolution-alar}
     |            |                 |                 |               |-gdu-notificatio
     |            |                 |                 |               |-gnome-panel
     |            |                 |                 |               |-gnome-power-man
     |            |                 |                 |               |-ibus-daemon-+-ibus-engine-pin
     |            |                 |                 |               |             |-ibus-gconf
     |            |                 |                 |               |             |-python
     |            |                 |                 |               |             `-{ibus-daemon}
     |            |                 |                 |               |-nautilus	// the gnome file manager.
     |            |                 |                 |               |-nm-applet	// network manager applet.
     |            |                 |                 |               |-polkit-gnome-au
     |            |                 |                 |               |-python
     |            |                 |                 |               |-ssh-agent
     |            |                 |                 |               |-update-notifier
     |            |                 |                 |               `-{gnome-session}
     |            |                 |                 `-{gdm-session-wo}
     |            |                 `-{gdm-simple-sla}
     |            `-{gdm-binary}
     |-6*[getty]
     |-gnome-keyring-d---3*[{gnome-keyring-}]
     |-gnome-screensav
     |-gnome-settings-
     |-gvfs-afc-volume---{gvfs-afc-volum}	// general video file server
     |-gvfs-fuse-daemo---3*[{gvfs-fuse-daem}]
     |-gvfs-gdu-volume
     |-gvfs-gphoto2-vo
     |-gvfsd
     |-gvfsd-metadata
     |-gvfsd-trash
     |-hald-+-hald-runner-+-hald-addon-acpi	// hald is a daemon that maintains a database of devices
						// connected to the system in real-time.
     |      |             |-hald-addon-cpuf
     |      |             |-hald-addon-inpu
     |      |             `-hald-addon-stor
     |      `-{hald}
     |-ibus-x11
     |-2*[indicator-apple]
     |-indicator-appli
     |-indicator-me-se
     |-indicator-messa
     |-indicator-sessi
     |-indicator-sound
     |-modem-manager
     |-notification-ar
     |-notify-osd	// 屏显通知系统
     |-polkitd	// polkitd provides the org.freedesktop.PolicyKit1 D-Bus on the system message bus.
     |-pulseaudio-+-gconf-helper
     |            `-2*[{pulseaudio}]
     |-rsyslogd---2*[{rsyslogd}]	// reliable and extendes syslogd
     |-rtkit-daemon---2*[{rtkit-daemon}]	// something about PulseAudio
     |-system-service-
     |-trashapplet
     |-udevd---2*[udevd]	// Linux configurable dynamic device naming support.
     |-udisks-daemon-+-udisks-daemon
     |               `-{udisks-daemon}
     |-upowerd	// provides the org.freedesktop.UPower service on the system message bus.
     |-upstart-udev-br
     |-wnck-applet	// GNome: wnck allows you to use the Window Navigator Construction Kit library
			// from perl to create things like destop switchers and taskbars.
     `-wpa_supplicant	// wpa_supplicant is a WPA Supplicant for Linux, BSD, Mac OS X, and Windows with 
			// support for WPA and WPA2.