VirtualBox - The VM session was closed before any attempt to power it on.

VirtualBox - The VM session was closed before any attempt to power it on.

Issue: "The VM session was closed before any attempt to power it on."

Solution :

#VirtualBox #Error #The VM session was closed before any attempt to power it on.

What is Wayland?

Wayland backgound/Features/Structure/X Window differences

Wayland background

- Started as a private project by Christian Hogsberg (KRH) in 2008, the developer of Red Hat .

- X code usability and very poor scalability(very heavy and large  => difficult to develop)

Designed about 30 years ago, X adds numerous extensions. -> functionality that is not in use, and many similar features are created(history is unknown)

Wayland Features

- WAYLAND is open source friendly and should be kept to a minimum. (KMS (Kernel-Mode Setting), EVDEV, PIXMAN, and so on... : make the most of external open sources to keep the inside to a minimum.)

- Local based (remote access uses protocols such as client layer VNC)

- support only Composite API (Support Direct Rendering/ Client-Side Decoration (CSD))

- Very Simple and Light! (X appears to improve what was so heavy and so big that it was difficult to develop)

Wayland structure

basic difference of X server and Wayland(X server vs. Wayland)

- X Server : independent process

- Wayland : Library (work of a compositor as a library)

A brief illustration of the structure of operation of the X server.

The process of updating the screen by receiving user input from the X client is expressed in order.

1. The X server sends user input to the X client.

2. The X client updates the required screen, and notifies the X server.

3. The X server informs the compositor that the X client's screen has been updated.

4. The compositor reflects the updated screen of the X client on the final screen, and informs the X server.

5. The X server reflects the final screen updated via KMS on the framebuffer.

A brief illustration of the structure of operation of the Wayland.

- WAYLAND and composites have been combined into one, reducing unnecessary messages to and from IPC.

Structure and Working differences

X Window

- Independent Process

- The server and compositor are separated.

- The server is responsible for rendering.

- The X server intermediates all behavior between clients, compositors, and kernels.

Wayland

- Implemented in library form, reducing OS overhead.

- Servers and compositors merge into one, reducing unnecessary communication.

- The rendering is handled by the client, reducing complexity with the server.

- The server intermediates only the client and kernel.

Result : Wayland advantage

• It is a framework that is lightened and organized compared to the existing X11 (X11).

• Remove parts not used by the existing X11 and implement only the necessary parts.

• Implement as simple as possible using standard GEM/DRM stack.

- User frameworks : no longer need to be complicated by supporting DRM/GEM in a kernel

• Used on Genivi platforms(GENIVI - related vehicle).

• 1/10 the size of X11.

#Wayland backgound #Wayland Features #Wayland Structure #Wayland X Window differences #vehicle #weston #wayland #genivi