I want to tell you how PC(Personal Computer) boots. I will keep it simple, details will be answered as per your interest.
Booting up (or simply Booting) is the process by which a computer system starts. And since this is my first post, I am talking about cold boot (hard boot) i.e. when your computer system is initially shut down. Other boots are: warm boot (soft boot) like when you restart your system... Or you can hibernate your system, thus the register values and RAM(Random Access Memory) is maintained with the contemporary ACPI(Advanced Configuration and Power Interface).
Also, I am taking only the hard disk as the booting option, i.e. Bootmgr is present and boot sector is intact. Do ask any questions after reading all this.
And these are the steps:
1. The power button is pressed, it sends the AC current to the SMPS (Switched Mode Power Supply) a power supply unit.
2. The SMPS stabilizes the power supply and thus the voltage can be further supplied to circuits.
3. Fans switch on, main circuit is the motherboard. Clock pulses of motherboard synchronize and since the RAM is empty, the CPU(Central Processing Unit) heads to ROM(Read Only Memory) and starts the BIOS(Basic Input-Output System) or EFI(Extensible Firmware Interface). (EFI and UEFI are meant to replace BIOS.)
4. As per the instruction on EFI, now a POST (Power On Self Test) is done by BIOS.
5. Devices which are connected to computed are found, first the video card. Then other devices are checked at all ports like mouse, keyboard, USB(Universal Serial Bus) ports. BIOS screen shows about everything connected, and the specifications of the devices.
6. And then, computer (or the CPU) has to decide which OS(Operating System) to boot. This is done is many ways in different OS(Operating Systems). in Linux, we have GRUB(GNU GRand Unified Bootloader), but we have other boot loaders in Windows, Macintosh, etc.
7. Then the MBR(Master Boot Record) starts secondary boot loader (bootmgr), which loads the remaining BIOS to RAM. In earlier versions, like XP, we had NTLDR.
8. Thus, the OS takes control of rest of the booting process like processing the kernel, allowing it to use(take control of) GUI, loading devices drivers, etc, and when everything is done the logon screen is shown.
source: All the OS I have studied in the 5th semester, and wikipedia. (in case I write the definitions)
please ask me doubts and/or give me feedback ^_^
Thank You.
Booting up (or simply Booting) is the process by which a computer system starts. And since this is my first post, I am talking about cold boot (hard boot) i.e. when your computer system is initially shut down. Other boots are: warm boot (soft boot) like when you restart your system... Or you can hibernate your system, thus the register values and RAM(Random Access Memory) is maintained with the contemporary ACPI(Advanced Configuration and Power Interface).
Also, I am taking only the hard disk as the booting option, i.e. Bootmgr is present and boot sector is intact. Do ask any questions after reading all this.
And these are the steps:
1. The power button is pressed, it sends the AC current to the SMPS (Switched Mode Power Supply) a power supply unit.
2. The SMPS stabilizes the power supply and thus the voltage can be further supplied to circuits.
3. Fans switch on, main circuit is the motherboard. Clock pulses of motherboard synchronize and since the RAM is empty, the CPU(Central Processing Unit) heads to ROM(Read Only Memory) and starts the BIOS(Basic Input-Output System) or EFI(Extensible Firmware Interface). (EFI and UEFI are meant to replace BIOS.)
4. As per the instruction on EFI, now a POST (Power On Self Test) is done by BIOS.
5. Devices which are connected to computed are found, first the video card. Then other devices are checked at all ports like mouse, keyboard, USB(Universal Serial Bus) ports. BIOS screen shows about everything connected, and the specifications of the devices.
6. And then, computer (or the CPU) has to decide which OS(Operating System) to boot. This is done is many ways in different OS(Operating Systems). in Linux, we have GRUB(GNU GRand Unified Bootloader), but we have other boot loaders in Windows, Macintosh, etc.
7. Then the MBR(Master Boot Record) starts secondary boot loader (bootmgr), which loads the remaining BIOS to RAM. In earlier versions, like XP, we had NTLDR.
8. Thus, the OS takes control of rest of the booting process like processing the kernel, allowing it to use(take control of) GUI, loading devices drivers, etc, and when everything is done the logon screen is shown.
source: All the OS I have studied in the 5th semester, and wikipedia. (in case I write the definitions)
please ask me doubts and/or give me feedback ^_^
Thank You.
