VFD System Viewer



VFD System Viewer is a hardware+software solution to present some system statistics to the user without making him login. It also serves as a nice display to place in the computer box if you have enough space.


Design and Implementation

The system was developed some years ago (probably around 2004) when my computer was trying to beat its last uptime record of 357 days online without a single reboot.

It displays several items in sequence:

  1. Greeting
  2. Date and time
  3. Load
  4. Uptime
  5. Type of CPU
  6. Users connected and their remote hosts


The hardware is a Vacuum fluorescent display (VFD) type CU20045SCPB-T (23A)  with 4 lines of text, each with 20 caracters. It supports brightness control and cursor positioning, among other things!



The software was written in C and is composed of:

In runtime it will use information provided by the proc filesystem and wtmp for the user information. It is possible to select the serial device to use and also to see the output on screen.

These are the options available:

me@ibook-powerpc:~/vfd-system-viewer-plain$ ./vfd_system_viewer -h
Invalid arguments.
Usage: vfd_system_viewer [-h] [-s serial_device] [screen|vfd|both]

        -h      shows this info

        -s serial_device
                changes the name of the serial device to use;
                the default is /dev/ttyS0

        screen  displays only on the current tty
        vfd     displays only on the vfd
        both    displays on both vfd and screen

        default is screen



Here's a video of the software running on my iBook.


Some screenshots









Published on Saturday 2008/06/14, last modified on Monday 2015/12/28