ubuntu18.04 准备回归wayland， 因为手机平板的ubuntu无人使用，开发成本太高。所以弃用Unity8, 重新改用 waylang 的GNOME
sudo systemctl disable gdm
sudo systemctl enable lightdm
Stop gdm with sudo systemctl stop gdm
Start lightdm with sudo systemctl start lightdm
1.Mir Mir is a display server technology.
https://en.wikipedia.org/wiki/Mir_(software)
https://wiki.ubuntu.com/Mir
目前 ubuntu 16.04~17.04 Unity8 默认都是用Mir, milestones ubuntu17.04 Zesty 应该会用上 Mir1.0
可以看到RPC用的是Google的 ProtoBuffer3 （估计是Unix Domain Socket(socket Pair), 共享内存还是太危险）
UNIX Domain Socket是在socket架构上发展起来的用于同一台主机的进程间通讯（IPC），它不需要经过网络协议栈，不需要打包拆包、计算校验和、维护序号和应答等，只是将应用层数据从一个进程拷贝到另一个进程。UNIX Domain Socket有SOCK_DGRAM或SOCK_STREAM两种工作模式，类似于UDP和TCP，但是面向消息的UNIX Domain Socket也是可靠的，消息既不会丢失也不会顺序错乱。
UNIX Domain Socket可用于两个没有亲缘关系的进程，是全双工的，是目前使用最广泛的IPC机制，比如X Window服务器和GUI程序之间就是通过UNIX Domain Socket通讯的。
Mir is a system-level component which supplies display & input services for shells and applications. It's currently shipping in our Ubuntu Touch products and is avialable on desktop as part of our Unity8 preview experience. This document outlines the motivation for the project, describes the high level design, summarizes the scope, and provides the roadmap of the Mir display server.
The purpose of Mir is to enable the development of the Unity8.
See the license section if you have question about Mir's licensing.
when a version 1.0 will be released? Mir is now an almost stable version, and I think, after the 0.26 version should be released the first stable version (1.0) then going to sanction the arrival of Mir and unity8 default on Ubuntu 17.04
2.LXqt LXQt is a lightweight Qt desktop environment.
2013年间，洪任諭PCMan启动了将 LXDE 移植到 Qt 的项目。LXDE-Qt 的首个预览版发布于2013年7月3日。而在2013年7月21日，Razor-qt（一个与LXDE类似的桌面）与 LXDE 宣布合并，产生了 LXQt。这个桌面集合了 Razor-qt 和 LXDE 的组件。尽管 LXDE 目前的精力已经集中到 LXQt，GTK+ 2 的版本依然在维护。
目前还在更新(虽然很少)。 个人不是很看好，轻量级qtUI库，qt 自己也有提供。
参考文档
http://lxqt.org/release/2017/01/14/0.3.2-release-lxqt-build-tools-and-more/
##### 1.安装lxqt
- 1.Download and install a command line Ubuntu installation using either the minimal image or the server image. Installing from Lubuntu is not yet supported. You can get a daily image from here: amd64 i386.
- 2.Boot into the install and log in.
* Run: sudo apt install lubuntu-qt-desktop.
* Select sddm as the default display manager.
- 3.This will fail. Do not worry, it's known. It should fail on plasma-workspace.
- 4.Run sudo apt remove sddm-theme-breeze lubuntu-default-settings lubuntu-extra-sessions && sudo apt autoremove. This will clean up dependencies.
- 5.Reboot!
----------------
注意点：
##### lxqt 如果是嵌入式板子用还好，（当然debian的UI也是可以） ，但是桌面lxqt做的还是差强人意(有bug)！！！ 最后我还是换回lightdm
###必须执行下面的操作，去掉plasma-workspace的依赖
```sh
sudo apt remove sddm-theme-breeze
sudo apt remove lubuntu-default-settings
sudo apt remove lubuntu-extra-sessions
sudo apt autoremove
使用lxqt
sudo dpkg-reconfigure ssdm
reboot
修复为原来的UI
- 进入任意tty*终端 ctrl + alt + F3
- 输入 sudo dpkg-reconfigure lightdm
- 修改启动界面
- reboot
其他
sudo dpkg-reconfigure lightdm或者sudo dpkg-reconfigure ssdm，执行后将显示如下界面
http://blog.csdn.net/dliyuedong/article/details/8813513
> 3.(wayland ](http://wayland.freedesktop.org/) Wayland is intended as a simpler replacement for X, easier to develop and maintain. GNOME and KDE are expected to be ported to it.
Wayland is intended as a simpler replacement for X, easier to develop and maintain. GNOME and KDE are expected to be ported to it.
2016年中旬就停止更新了
Wayland is a protocol for a compositor to talk to its clients as well as a C library implementation of that protocol. The compositor can be a standalone display server running on Linux kernel modesetting and evdev input devices, an X application, or a wayland client itself. The clients can be traditional applications, X servers (rootless or fullscreen) or other display servers.
Part of the Wayland project is also the Weston reference implementation of a Wayland compositor. Weston can run as an X client or under Linux KMS and ships with a few demo clients. The Weston compositor is a minimal and fast compositor and is suitable for many embedded and mobile use cases.
https://en.wikipedia.org/wiki/Wayland_(display_server_protocol)
Wayland is a computer protocol that specifies the communication between a display server (called a Wayland compositor[clarification needed]) and its clients, as well as a reference implementation of the protocol in the C programming language.[6]
https://wiki.ubuntu.com/Wayland
#### *** Please note that we are no longer considering Wayland, but instead we will be moving to Mir. ***