Minimum GUI on headless Ubuntu


The minimum installation to run GUI application on Ubunut 16 server version locally.
Minimum means two things:
1. No Windows Manager, and therefore, of course, no desktop either
2. Show GUI locally. If show GUI on remote, no installation needed on local server.

The only thing we need is xorg.
The commands:
Install: $ sudo apt-get install xorg
Run xint:
$ xinit /usr/bin/xmessage xmessageHello -display :0 -geometry 200×200+50+100 — /etc/X11/xinit/xserverrc :0 vt1 -keeptty
This brings up a GUI message box.
Bring up GUI on a different terminal when ssh from Windows to Linux:
Issue command on Windows ssh and show GUI on Linux:
[ssh]$ xmessage -center myhello -display :0
0 means the x server running on local tty1
Issue command on Linux and show GUI on Windows VcXsrv:
$ xclock -geometry 200×200+50+100 -display localhost:10.0
10.0 is the display VcXsrv on Windows done by x11 forwarding. screen shot attached.

GuiOnWin

Some notes:
Since no Windows Manager, cannot move the window, and no default close button.

Advertisements

Placeholder


thinking build for Roku

git: link vs junction


Sometimes I want to use a single repo to track part of multiple projects. For example, on NTFS:
\BigProjectA is too big, and I only track subfolder \BigProjectA\source, with \Git under git control
At end, I have \Git\sourceA to track \BigProjectA\source

I could have \BigProjectA\source as a symbolic link linking to \Git\sourceA, but some application, like IIS , have trouble handling links.
Therefore, I turn it around, \Git\sourceA as link linking to \BigProjectA\source as created by:
mklink /s \Git\sourceA \BigProjectA\source
This didn’t work because git cannot follow symbolic links.
However, git does follow junctions, as created by:
mklink /j \Git\sourceA \BigProjectA\source
The root difference between NTFS Junction and Symbolic Link remains vague, in the context of directories in the same file system.

5G FAQ


How fast is 5G?
At least 10 times faster than 4G, about 2Gbps.
Why is 5G so fast?
High frequency, over 30GHz, higher than 5GHz 802.11ac wifi, therefore more channels
Why is 5G hard to build?
Requires 100 times more base stations than 4G
4G tower covers 2km, while 5G tower cover 200 meters.
Other benefit of 5G:
smaller antenna, shorter than 1 cm,
Antenna size is proportional to wave length, and 5G is mm wave.