Hardware
- Power source (wall -> LC -> UPS)
- Power Supply (PSU)
- "power good" signal + related mb timer/reset circuitry
Firmware
- BIOS (legacy systems 5-yrs+)
- BIOS handoff to UEFI (virtually all current systems: 1 + 4)
- UEFI handoff to legacy BIOS (emerging)
- UEFI (near future)
Software
Hard (cold) Boot and Soft (warm) boot
- Hardware-induced (hard/cold boot, external events)
- power button quick press (ATX specs normal, ACPI signal)
- power button long press (ATX specs override/forced)
- de-energizing
- power switch (mechanical make/break)
- power cord disconnect
- physical power event
- pressing & releasing reset button
- Software-induced Boot
- Ctrl-Alt-Del
- direct (as in DOS)
- via Windows Security Menu selection
- Windows 8.x Start Screen / Charms
- Shutdown Menu
- Application initiated, via API, as is typical after install/upgrade
- Batch scripts/CLI
In a modern IBM-PC compatible system, the difference between hard/soft boot
amounts to this: soft boot bypasses the first 2 phases (see section below). More
precisely: warm boot branches to the step just before phase 3. The practical
effect is shorter boot time, due to skipping of power supply waiting,
firmware-based hardware detection, and BIOS loaded (non-native to motherboard
and the original IBM-PC architecture) storage initialization.
Boot Process of x86/x64 NT5.x
- Hardware Phase
- Power supply, power-good signal
- motherboard timer
- reset button state
- Firmware Phase
- BIOS POST
- BIOS PnP reorganization
- BIOS storage (RAID, SATA card, SCSI, etc.)
- RAID hotkey: init/config/status menu, etc.
- BIOS boot device priority setting
- Keyboard override detect
(BIOS or UEFI+CSM, else more complicated)
- OS-independent boot-loader phase
- MBR of top priority device (GPT more complicated)
- parse partition table, goto active partition
- OS real-mode phase
- OS Windows phase
- BOOT.ini os selection, user prompt, timeout default
- NTDETECT
- NTBOOTDD
- NTLDR
- Hardware Profile, prompt, timeout default
- NTOSKRNL.exe
- HAL.dll
- Windows Logo Flag animation <<<<
- HKEY_LOCAL_MACHINE
- device drivers
- services
- All Users StartUp
- User Logon
- phase 3 drivers (in background)
- LSASS
- LANMAN
- HKEY_CURRENT_USER
- successful login
- clone profile as "last known good"
- control is passed to user
NT6 is boot process is similar
to NT5,
except for the following file differences |
NT4, NT5 |
NT6 |
NTLDR |
BOOTMGR |
bootini |
BCD |
Most probable cause:
- HD/CD/DVD
- PSU
- MB
- Mem