I applied package updates including security fixes to all workstations.

-----
k1ctr12@PSL is now link to 100Mbps.
A situation was not improved by power cycles in a few times.
Degradation of a LAN cable, a network switch, etc is required.

k1ctr13@PR-booth has now no display.
Any display cannot be found even if the workstation was rebooted.
It's necessary to check the connection of a display cable and power line of the display.

k1ctr14@IXV and k1ctr15@IYV hung up, so I recovered them in the mine before this update work.
On them, root directory '/' cannot be accessed due to Input/Output error, so any fundamental commands cannot be found.
M.2 NVMe SSD may be degraded.