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Booting Process Of Android Devices
The booting process of Android devices starts at the power-on of the SoC (system on a chip) and ends at the visibility of the home screen, or special modes like recovery and fastboot. The boot process of devices that run Android is influenced by the firmware design of the SoC manufacturers. Background As of 2018, 90% of the SoCs of the Android market are supplied by either Qualcomm, Samsung or MediaTek. Other vendors include Rockchip, Marvell, Nvidia and previously Texas Instruments. History Verified boot was introduced with Android KitKat. Stages Primary Bootloader The Primary Bootloader (PBL), which is stored in the Boot ROM is the first stage of the boot process. This code is written by the chipset manufacturer. The PBL verifies the authenticly of the next stage. On Samsung smartphones, the Samsung Secure Boot Key (SSBK) is used by the boot ROM to verify the next stages. On SoCs from Qualcomm, it is possible to enter the Qualcomm Emergency Download Mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Booting
In computing, booting is the process of starting a computer as initiated via hardware such as a button or by a software command. After it is switched on, a computer's central processing unit (CPU) has no software in its main memory, so some process must load software into memory before it can be executed. This may be done by hardware or firmware in the CPU, or by a separate processor in the computer system. Restarting a computer also is called rebooting, which can be "hard", e.g. after electrical power to the CPU is switched from off to on, or "soft", where the power is not cut. On some systems, a soft boot may optionally clear RAM to zero. Both hard and soft booting can be initiated by hardware such as a button press or by a software command. Booting is complete when the operative runtime system, typically the operating system and some applications,Including daemons. is attained. The process of returning a computer from a state of sleep (suspension) does not involve bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EMMC
The MultiMediaCard, officially abbreviated as MMC, is a memory card standard used for solid-state storage. Unveiled in 1997 by SanDisk and Siemens, MMC is based on a surface-contact low pin-count serial interface using a single memory stack substrate assembly, and is therefore much smaller than earlier systems based on high pin-count parallel interfaces using traditional surface-mount assembly such as CompactFlash. Both products were initially introduced using SanDisk NOR-based flash technology. MMC is about the size of a postage stamp: 32 mm × 24 mm × 1.4 mm. MMC originally used a 1-bit serial interface, but newer versions of the specification allow transfers of 4 or 8 bits at a time. MMC can be used in many devices that can use Secure Digital (SD) cards. Typically, an MMC operates as a storage medium for devices, in a form that can easily be removed for access by a PC via a connected MMC reader. Modern computers, both laptops and desktops, often have SD slo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Booting Process Of Windows
The booting process of Microsoft Windows varies between different releases. DOS-based Windows Windows 1.x/2.x In Windows versions 1.01 to Windows 2.11, the system was loaded when WIN.COM was executed. It then loaded WIN100.BIN or WIN200.BIN and WIN100.OVL or WIN200.OVL, along with the configuration settings file WIN.INI. The default shell is the MS-DOS Executive. The modules GDI.EXE, KERNEL.EXE and USER.EXE, fonts, and the various device drivers (such as COMM.DRV, MOUSE.DRV, KEYBOARD.DRV) are incorporated in WIN100.BIN/WIN200.BIN and WIN100.OVL/WIN200.OVL. Windows 3.x/9x In Windows 3.x and 95/98/ME, the boot loader phase is handled by MS-DOS. During the boot phase, CONFIG.SYS and AUTOEXEC.BAT are executed, along with the configuration settings files WIN.INI and SYSTEM.INI. Virtual device drivers are also loaded in the startup process: they are most commonly loaded from the registry (HKLM\System\CurrentControlSet\Services\VxD) or from the SYSTEM.INI file. When all system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coreboot
coreboot, formerly known as LinuxBIOS, is a software project aimed at replacing proprietary firmware (BIOS or UEFI) found in most computers with a lightweight firmware designed to perform only the minimum number of tasks necessary to load and run a modern 32-bit or 64-bit operating system. Since coreboot initializes the bare hardware, it must be ported to every chipset and motherboard that it supports. As a result, coreboot is available only for a limited number of hardware platforms and motherboard models. One of the coreboot variants is Libreboot, a software distribution fully free of proprietary blobs, aimed at end users. History The coreboot project began in the winter of 1999 in the Advanced Computing Laboratory at Los Alamos National Laboratory (LANL), with the goal of creating a BIOS that would start fast and handle errors intelligently. It is licensed under the terms of the GNU General Public License version 2 (GPLv2). Main contributors include LANL, SiS, AMD, Core ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GUID Partition Table
The GUID Partition Table (GPT) is a standard for the layout of partition tables of a physical computer storage device, such as a hard disk drive or solid-state drive, using universally unique identifiers, which are also known as globally unique identifiers (GUIDs). Forming a part of the Unified Extensible Firmware Interface (UEFI) standard (Unified EFI Forum-proposed replacement for the IBM PC, PC BIOS), it is nevertheless also used for some BIOS systems, because of the limitations of master boot record (MBR) partition tables, which use 32 bits for logical block addressing (LBA) of traditional 512-byte disk sectors. All modern personal computer operating systems support GPT. Some, including macOS and Microsoft Windows on the x86 architecture, support booting from GPT partitions only on systems with EFI firmware, but FreeBSD and most Linux distributions can boot from GPT partitions on systems with either the BIOS or the EFI firmware interface. History The Master Boot Record (M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Partitioning
Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions. It is typically the first step of preparing a newly installed disk, before any file system is created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk. Each partition then appears to the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize, delete, and manipulate the partitions. Partitioning allows the use of different filesystems to be installed for different kinds of files. Separating user data from system data can prevent the system partition from becoming full and rendering the system unusable. Partitioning can also make backing up easier. A disadvantage is that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fork (system Call)
In computing, particularly in the context of the Unix operating system and its workalikes, fork is an operation whereby a process creates a copy of itself. It is an interface which is required for compliance with the POSIX and Single UNIX Specification standards. It is usually implemented as a C Standard Library (libc) wrapper to the fork, clone, or other system calls of the kernel. Fork is the primary method of process creation on Unix-like operating systems. Overview In multitasking operating systems, processes (running programs) need a way to create new processes, e.g. to run other programs. Fork and its variants are typically the only way of doing so in Unix-like systems. For a process to start the execution of a different program, it first forks to create a copy of itself. Then, the copy, called the "child process", calls the exec system call to overlay itself with the other program: it ceases execution of its former program in favor of the other. The fork operation crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cpio
cpio is a general file archiver utility and its associated file format. It is primarily installed on Unix-like computer operating systems. The software utility was originally intended as a tape archiving program as part of the Programmer's Workbench (PWB/UNIX), and has been a component of virtually every Unix operating system released thereafter. Its name is derived from the phrase ''copy in and out'', in close description of the program's use of standard input and standard output in its operation. All variants of Unix also support other backup and archiving programs, such as tar, which has become more widely recognized. The use of cpio by the RPM Package Manager, in the initramfs program of Linux kernel 2.6, and in Apple's Installer (pax) make cpio an important archiving tool. Since its original design, cpio and its archive file format have undergone several, sometimes incompatible, revisions. Most notable is the change, now an operational option, from the use of a binary forma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gzip
gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and intended for use by GNU (from where the "g" of gzip is derived). Version 0.1 was first publicly released on 31 October 1992, and version 1.0 followed in February 1993. The decompression of the ''gzip'' format can be implemented as a streaming algorithm, an important feature for Web protocols, data interchange and ETL (in standard pipes) applications. File format gzip is based on the DEFLATE algorithm, which is a combination of LZ77 and Huffman coding. DEFLATE was intended as a replacement for LZW and other patent-encumbered data compression algorithms which, at the time, limited the usability of compress and other popular archivers. "gzip" is often also used to refer to the gzip file format, which is: * a 10-byte header, contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embedded System
An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use today. , it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems. Modern embedded systems are often based on microcontrollers (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case, the processor(s) used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microkernel
In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, thread management, and inter-process communication (IPC). If the hardware provides multiple rings or CPU modes, the microkernel may be the only software executing at the most privileged level, which is generally referred to as supervisor or kernel mode. Traditional operating system functions, such as device drivers, protocol stacks and file systems, are typically removed from the microkernel itself and are instead run in user space. In terms of the source code size, microkernels are often smaller than monolithic kernels. The MINIX 3 microkernel, for example, has only approximately 12,000 lines of code. History Microkernels trace their roots back to Danish computer pioneer Per Brinch Hansen and his tenure in Danish computer compan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Das U-Boot
Das U-Boot (subtitled "the Universal Boot Loader" and often shortened to U-Boot; see ''History'' for more about the name) is an open-source, primary boot loader used in embedded devices to package the instructions to boot the device's operating system kernel. It is available for a number of computer architectures, including 68k, ARM, Blackfin, MicroBlaze, MIPS, Nios, SuperH, PPC, RISC-V and x86. Functionality U-Boot is both a first-stage and second-stage bootloader. It is loaded by the system's ROM (e.g. onchip ROM of the ARM CPU) from a supported boot device, such as an SD card, SATA drive, NOR flash (e.g. using SPI or I²C), or NAND flash. If there are size constraints, U-Boot may be split into two stages: the platform would load a small SPL (Secondary Program Loader), which is a stripped-down version of U-Boot, and the SPL would do some initial hardware configuration (e.g. DRAM initialization using CPU cache as RAM) and load the larger, fully featured version of U-Boot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
