Linux System Basic Diagnostic Startup Process

Normal Linux system basic diagnostic startup process involves:

System Power Drain

KVM ( Keyboard-Video-Mouse ) Connection

NIC ( Network Interface Card ) Connection

System Power On

BIOS ( Basic Input/Output System ) / UEFI Setup Access

POST ( Power On Self Test )

GRUB ( Grand Unified Bootloader ) Menu and OS ( Operating System ) Kernel Load

Login

  Power Drain PSU ( Power Supply Unit ) -

Shutdown system.

Drain PSU.

Drain Workstation ATX PSU

Disconnect AC power cable from ATX PSU.

Move ATX PSU main power switch to ' off ' position.

Allow the system to rest this way for a minute.

Reconnect AC power cable.

Move PSU main power switch to ' on ' position.

Note state of LEDs.

Drain Server Modular PSU

Disconnect AC power cables from all PSU modules.

Remove all PSU modules from slots.

Allow the system to rest this way for a minute.

Replace all PSU modules into their respective slots.

Reconnect all AC power cables.

Note state of all LEDs.

Keyboard-Video-Mouse ( KVM ) Connection -

Connect a known good USB keyboard and mouse to USB ports on the backplane of the computer.

Ideally, one of the GPUs will have been identified with a sticker on the back plane as the active/default video output device.

Initially, a port from this device will output a display signal at startup.

If no display is detected from any GPU port, it will be necessary to connect the monitor to the onboard VGA port ( blue socket with nine pin holes ) .

Always power cycle the monitor prior to starting the system and whenever switching video ports.

  Network Adapter ( Interface Card ) ( NIC ) Connection -

Provision a known good LAN ( Local Area Network ) connection.

The connection must pass through a reliable Cat5 or Cat6 Ethernet cable.

If possible, verify cable Ethernet network connectivity with another known good system; or, request IT LAN Support to verify Ethernet connectivity.

When connecting a network cable; normally, two LEDs on the NIC port will illuminate.

One will be steady, the other may blink.

Colors may vary; however, they are normally green or amber.

System Power On -

Note power on symptoms -

Audible beep sequences

Two digit hexa-decimal characters on the display or system board

Vendor logo splash screen

System configuration or error messages

State ( steady or blinking ) and color of all visible LEDs

Fan activity ( not moving, spinning slowly or changing speed )

Attempt to restart with keyboard or power button inputs -

Attempt to restart the system with <Ctl+Alt+Del> key combination

... or ...

Attempt to restart the system by holding the power button

… or …

Attempt to ' wake up ' the system by clicking mouse buttons.

Access BIOS/UEFI setup -

Restart the system.

Hold <Del> or <F2> or <Esc> key at power on.

If successful, do not make or save any changes; simply exit without changing BIOS/UEFI settings.

POST ( Power On Self Test ) -

The computer will perform a series of automated self-diagnostics.

These activities will vary depending on vendor, hardware and custom configuration.

No input is necessary during this stage of startup.

Make note of system messages or errors.

Select GRUB Menu Option and Load OS Kernel -

The GRUB menu will appear after a successful POST.

BIOS/UEFI will turn over control of the system configuration to GRUB ( Grand Unified Bootloader ) to load and initialize the operating system ( OS ) kernel.

The GRUB menu normally presents options for choosing an OS kernel and additional boot related configurations.

Sometimes the GRUB menu will immediately load a default OS kernel and present a GUI ( Graphical User Interface ) desktop or TUI ( Text-based User Interface ) ; the latter is often referred to as a terminal.

If the GRUB menu does not appear; it can be forced to appear by holding a <Shft> or <Esc> key at power on.

Note if a ' Recovery ' option is included in the GRUB menu.

Select an OS kernel to load from the GRUB ( Grand Unified Bootloader ) menu; normally, the first or top choice is normally the most recent and up-to-date version of the OS kernel and is preferred.

If no GRUB menu option is selected; GRUB will time-out and load a default option.

A successful startup will result with a login prompt.