Fix slow USB mouse response on my Chromium OS

I have a cordless USB mouse Lenovo N50 connected to a MSI X340 laptop with Chromium OS installed on it. The same mouse works flawlessly on a Chromebook Acer C720 but it gets very slow response on the X340 with Chromium OS ArnoldTheBats build. The mouse cursor's movement on the screen always lags that of the actual mouse by noticeable amount of time. I've tried changing the mousing setting in Chromium browser or xset in console but neither worked. However, today I was able to fix it after updating the Chromium OS to the latest build by following the steps below:

1. Set my own password for root user: Go to Developer Console in Chromium (push keys Ctrl- Alt-F2) and log in as user "chronos" with initial password "password". Then type the following command:
sudo chromeos-setdevpasswd
   and enter the new password
2. Become root user by typing the following command:
sudo su
   and enter the password set in the previous step
3. Check network status with the following command:
ifconfig In my case, the wireless interface wlan0 is not connected under developer console as no IP address is shown under wlan0. I had to connect an ethernet cable to the laptop to get interface eth0 up. 
4. Update Chromium OS to the latest build with the following command: update_engine_client --update --omaha_url=http://chromebld.arnoldthebat.co.uk:8080/update
5. (May not be necessary) After the above update is successful, type the following command:
sudo stateful_update In my case, this command actually failed.
6. Try updating the system again as the previous command failed:
update_engine_client --update
sudo stateful_update No need to supply the –omaha-url any more in future updates. It showed that the update succeeded and system needs reboot.
7. Reboot the system and now the mouse is as responsive as on the other Chromebook
8. Reinstall the Flash plugin: the update was 32-bit, so I used the first instruction below with the link http://goo.gl/FrT7Q6
• 32-bit Chromium OS: uname output i686
• 64-bit Chromium OS: uname output x86_64

Install Samba 4.1 AD DC on CentOS 7 with yum

CentOS 7's bundled Samba 4 does not provide Active Directory (AD) Domain Controller (DC) functionality due to the incompatibility between the Kerberos 5 libraries used by a Samba 4 AD DC (Heimdal) and those by RHEL/CentOS (MIT). However, Samba 4 binaries (rpms) compiled with Heimdal Kerberos library for CentOS 7 can be obtained from the Sernet Samba repository without the need of compiling Samba from its source code.

To download the rpm files with yum, a user account is necessary at the Sernet Samba repository. Signing up for a user account at Sernet is totally free and can be done in a minute. Upon successful registration, one can log into the portal and obtain a yum repo file with his username and password embedded in the repo URL. The repo file can be copied to /etc/yum.repos.d and one can then use yum to install the necessary rpms for a Samba 4 AD DC on CentOS 7.

If the bundled Samba 4 was installed in the system, remove it with yum first.
 yum remove samba*
The following Samba 4.1 rpms can then be installed from Sernet on CentOS 7 to enable a AD DC
sernet-samba-libs-4.1.14-9.el7.x86_64
sernet-build-key-1.1-4.noarch
sernet-samba-common-4.1.14-9.el7.x86_64
sernet-samba-libsmbclient0-4.1.14-9.el7.x86_64
sernet-samba-4.1.14-9.el7.x86_64
sernet-samba-winbind-4.1.14-9.el7.x86_64
sernet-samba-ad-4.1.14-9.el7.x86_64
sernet-samba-client-4.1.14-9.el7.x86_64

If there is existing Samba 3 NT4-style domain, it can be upgraded to AD type domain with samba-tool, which is installed as part of the packages above. The following Samba Classic Upgrade wiki guide provides excellent instructions on the upgrade. For simplicity,  one can use Samba 4's built-in DNS server for the AD DC. After the upgrade is complete, start the AD DC by
service sernet-samba-ad start
and test it following this guide.