May the screen/keyboard be dedicated to a unique (background/non-root) process?

Question

Consider an industrial computer (say "embedded system"),

• equipped with a linux server OS (no desktop)
• running just a SINGLE application process (a single non-root user)
• attached to an high resolution screen
• attached with a keyboard

The computer fully dedicated to a SINGLE application process/user,

• running in background (to be defined) and started at boot
• run some I/O logics
• get some user inputs (keystrokes/digits) from the keyboard
• has to display some text/images on a screen attached to the computer

BTW, for text display details see also the related question: display big texts (on a graphic mode?) without a desktop environment).

    linux server host (no desktop env)
    +-------------------------------------------+
    |                                           |
    |                                           +--------> Digital inputs
    |   +--------------+                        <--------- Digital outputs
    |   | graphic card |                        |
    +---+------+-------+--------------------^---+
               |                            |
               | HDMI / VGA                 | USB
+--------------v---------------+    +-------+--------+
| Please contact the operator. |    |                |
+------------------------------+    +----------------+
      screen (TTY console?)              keyboard

How can the (background) process print text (in text-terminal mode or in graphic mode) on the attached (dedicated) screen, and get keystrokes from the keyboard?

OUTPUT

For output, I presume that one solution is that the process prints output texts as images, directly writing on the framebuffer (by example using program fbi.

But how if I would use the screen as a stdout of the (background) process? In this case I guess I need to "uncouple" the root TTY from the attached screen (that's possible?), allowing the user process to get the full control of the screen. It make sense?

INPUT

How can I take keystrokes from the keyboard? Using the stdin? Reading the keyboard device directly?

---

BTW, I presume to access the computer for any (root) need, over SSH.

Any suggestion?

Answer 1

If you are asking. How can I set up a system with a single graphical application, but no window-manager, start-button, task-bar, etc?

Then.

You just need to not run the desktop: Window manager, and panel. There are just other processes. The process that starts the X11 server, will also start these. You just need to change the configuration.