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Boot Loader
A bootloader, also spelled as boot loader or called bootstrap loader, is a computer program that is responsible for booting a computer and booting an operating system. If it also provides an interactive menu with multiple boot choices then it's often called a boot manager. When a computer is turned off, its softwareincluding operating systems, application code, and dataremains stored on non-volatile memory. When the computer is powered on, it typically does not have an operating system or its loader in random-access memory (RAM). The computer first executes a relatively small program stored in the boot ROM, which is read-only memory (ROM, and later EEPROM, Flash memory#NOR flash, NOR flash) along with some needed data, to initialize hardware devices such as CPU, motherboard, memory, storage and other I/O devices, to access the nonvolatile device (usually Device file#Block devices, block device, e.g., NAND flash) or devices from which the operating system programs and data can be l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRUB V2
GNU GRUB (short for GNU GRand Unified Bootloader, commonly referred to as GRUB) is a boot loader package from the GNU Project. GRUB is the reference implementation of the Free Software Foundation's Multiboot Specification, which provides a user the choice to boot one of multiple operating systems installed on a computer set up for multi-booting or select a specific Kernel (operating system), kernel configuration available on a particular operating system's partitions. GNU GRUB was developed from a package called the ''Grand Unified Bootloader'' (a play on Grand Unified Theory). It is predominantly used for Unix-like systems. Operation Booting When a computer is turned on, its BIOS finds the primary bootable device (usually the computer's hard disk) and runs the initial Bootstrapping (computing), bootstrap program from the master boot record (MBR). The MBR is the first Disk sector, sector of the hard disk. This bootstrap program must be small because it has to fit in a sin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UEFI
Unified Extensible Firmware Interface (UEFI, as an acronym) is a Specification (technical standard), specification for the firmware Software architecture, architecture of a computing platform. When a computer booting, is powered on, the UEFI implementation is typically the first that runs, before starting the operating system. Examples include AMI Aptio, Phoenix Technologies, Phoenix SecureCore, TianoCore EDK II, and InsydeH2O. UEFI replaces the BIOS that was present in the boot ROM of all personal computers that are IBM PC compatible, although it can provide Backward compatibility, backwards compatibility with the BIOS using #CSM booting, CSM booting. Unlike its predecessor, BIOS, which is a de facto standard originally created by IBM as proprietary software, UEFI is an open standard maintained by an industry consortium. Like BIOS, most UEFI implementations are proprietary. Intel developed the original ''Extensible Firmware Interface'' (''EFI'') specification. The last Inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safe Mode
Safe mode is a diagnosis, diagnostic mode of a computer operating system (OS). It can also refer to a mode of operation by application software. ''Safe mode'' is intended to help fix most, if not all, problems within an operating system. It is also widely used for removing rogue security software. Background Microsoft Windows, macOS, Android (operating system), Android and Linux distributions such as Ubuntu (operating system), Ubuntu and Linux Mint are examples of contemporary operating systems that implement a safe mode as well as other complex electronics, electronic devices. In safe mode, an operating system has reduced functionality, but the task of isolating problems is easier since many non-core components are disabled, such as sound. An installation that will only booting, boot into safe mode typically has a major problem, such as disk corruption or the installation of poorly-configured software that prevents the operating system from successfully booting into its norma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-booting
Multi-booting is the act of installing multiple operating systems on a single computer, and being able to choose which one to boot. The term dual-booting refers to the common configuration of specifically two operating systems. Multi-booting may require a custom boot loader. Usage Multi-booting allows more than one operating system to reside on one computer; for example, if a user has a primary operating system that they use most frequently and an alternate operating system that they use less frequently. Multi-booting allows a new operating system to configure all applications needed and migrate data before removing the old operating system, if desired. Another reason for multi-booting can be to investigate or test a new operating system without switching completely. Multi-booting is also useful in situations where different software requires different operating systems. A multi-boot configuration allows a user to use all of their software on one computer. This is often accompl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel (operating System)
A kernel is a computer program at the core of a computer's operating system that always has complete control over everything in the system. The kernel is also responsible for preventing and mitigating conflicts between different processes. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the use of common resources, such as CPU, cache, file systems, and network sockets. On most systems, the kernel is one of the first programs loaded on startup (after the bootloader). It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit. The critical code of the kernel is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Initial Ramdisk
In Linux systems, initrd (''initial ramdisk'') is a scheme for loading a temporary root file system into computer memory, memory, to be used as part of the Linux startup process. initrd and initramfs (from INITial RAM File System) refer to two different methods of achieving this. Both are commonly used to make preparations before the real root directory, root file system can be mount (Unix), mounted. Rationale Many Linux distributions ship a single, generic Linux kernel image one which the distribution's developers create specifically to boot on a wide variety of hardware. The device drivers for this generic kernel image are included as loadable kernel modules because statically compiling many drivers into one kernel causes the kernel image to be much larger, perhaps too large to boot on computers with limited memory, or in some cases to cause boot-time crashes or other problems due to probing for nonexistent or conflicting hardware. This static-compiled kernel approach also leaves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Device Driver
In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details about the hardware being used. A driver communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface. Purpose The main purpose of device drivers is to provide abstraction b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTLDR
NTLDR (abbreviation of ''NT loader'') is the boot loader for all releases of Windows NT operating system from 1993 with the release of Windows NT 3.1 up until Windows XP and Windows Server 2003. From Windows Vista onwards it was replaced by the BOOTMGR bootloader. NTLDR is typically run from the primary storage device, but it can also run from portable storage devices such as a CD-ROM, USB flash drive, or floppy disk. NTLDR can also load a non NT-based operating system given the appropriate boot sector in a file. NTLDR requires, at the minimum, the following two files to be on the system volume: * , the main boot loader itself * , required for booting an NT-based OS, detects basic hardware information needed for successful boot An additional important file is ''boot.ini'', which contains boot configuration (if missing, NTLDR will default to ''\Windows'' on the first partition of the first hard drive). NTLDR is launched by the volume boot record of system partition, which is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Boot Manager
The Windows Boot Manager (BOOTMGR) is the bootloader provided by Microsoft for Windows NT versions starting with Windows Vista and Windows Server 2008. It is the first program launched by the BIOS or UEFI of the computer and is responsible for loading the rest of Windows. It replaced the NTLDR present in older versions of Windows. The boot sector or UEFI loads the Windows Boot Manager (a file named BOOTMGR on either the system or the boot partition), accesses the Boot Configuration Data store and uses the information to load the operating system through winload.exe or winresume.exe on BIOS systems, and winload.efi and winresume.efi on UEFI systems. Launching On system with BIOS firmware, the BIOS invokes MBR boot code from a hard disk drive at startup. The MBR boot code and the VBR boot code are OS-specific. In Microsoft Windows, the MBR boot code tries to find an active partition (the MBR is only 512 bytes), then executes the VBR boot code of an active partition. The VB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
REFInd
rEFInd is a boot manager for UEFI and EFI-based machines. It can be used to boot multiple operating systems that are installed on a single non-volatile device. It also provides a way to launch UEFI applications. It was forked from discontinued rEFIt in 2012, with 0.2.0 as its first release. rEFind supports the IA-32, x86-64, and AArch64 architectures. Features rEFInd has several features: * Automatic operating systems detection. * Customisable OS launch options. * Graphical or text mode. Theme is customisable. * Mac-specific features, including spoofing booting process to enable secondary video chipsets on some Mac. * Linux-specific features, including autodetecting EFI stub loader to boot Linux kernel directly and using fstab in lieu of rEFInd configuration file for boot order. * Support for Secure Boot. Adoption rEFInd is the default UEFI boot manager for TrueOS. rEFInd is included in official repositories of major Linux distributions. Development GNU-EFI and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU GRUB
GNU GRUB (short for GNU GRand Unified Bootloader, commonly referred to as GRUB) is a boot loader package from the GNU Project. GRUB is the reference implementation of the Free Software Foundation's Multiboot Specification, which provides a user the choice to boot one of multiple operating systems installed on a computer set up for multi-booting or select a specific Kernel (operating system), kernel configuration available on a particular operating system's partitions. GNU GRUB was developed from a package called the ''Grand Unified Bootloader'' (a play on Grand Unified Theory). It is predominantly used for Unix-like systems. Operation Booting When a computer is turned on, its BIOS finds the primary bootable device (usually the computer's hard disk) and runs the initial Bootstrapping (computing), bootstrap program from the master boot record (MBR). The MBR is the first Disk sector, sector of the hard disk. This bootstrap program must be small because it has to fit in a sin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
