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IBoot
iBoot is the stage 2 bootloader for all Apple products. It replaces the old bootloader, BootX. Compared with its predecessor, iBoot improves authentication performed in the boot chain. For x86 macOS, the boot process starts by running code stored in secured UEFI Boot ROM (first stage). Boot ROM has two primary responsibilities: to initialize system hardware and to select an operating system to run (the POST and UEFI component). For ARM macOS, the Boot ROM is not UEFI component. For iOS, the boot process starts by running the device's Boot ROM code. In systems with S1 processors or A9 or earlier A-series processors, the Boot ROM loads the Low-Level Bootloader (LLB), which loads iBoot. In systems with newer processors, the Boot ROM loads iBoot itself. If all goes well, iBoot will then proceed to load the iOS kernel as well as the rest of the operating system. If the LLB or iBoot fails to load iOS, or fails to verify iOS, the bootloader jumps to DFU (Device Firmware Update) mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boot Loader
A bootloader, also spelled as boot loader or called boot manager and bootstrap loader, is a computer program that is responsible for booting a computer. 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 read-only memory (ROM, and later EEPROM, NOR flash) along with some needed data, to initialize RAM (especially on x86 systems), to access the nonvolatile device (usually block device, eg NAND flash) or devices from which the operating system programs and data can be loaded into RAM. Some earlier computer systems, upon receiving a boot signal from a human operator or a peripheral device, may load a very small number of fixed instructions into memory at a specific location, initialize at least one CPU, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bootloader
A bootloader, also spelled as boot loader or called boot manager and bootstrap loader, is a computer program that is responsible for booting a computer. 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 read-only memory (ROM, and later EEPROM, NOR flash) along with some needed data, to initialize RAM (especially on x86 systems), to access the nonvolatile device (usually block device, eg NAND flash) or devices from which the operating system programs and data can be loaded into RAM. Some earlier computer systems, upon receiving a boot signal from a human operator or a peripheral device, may load a very small number of fixed instructions into memory at a specific location, initialize at least one CPU, and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apple Inc
Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company by market capitalization, the fourth-largest personal computer vendor by unit sales and second-largest mobile phone manufacturer. It is one of the Big Five American information technology companies, alongside Alphabet, Amazon, Meta, and Microsoft. Apple was founded as Apple Computer Company on April 1, 1976, by Steve Wozniak, Steve Jobs and Ronald Wayne to develop and sell Wozniak's Apple I personal computer. It was incorporated by Jobs and Wozniak as Apple Computer, Inc. in 1977 and the company's next computer, the Apple II, became a best seller and one of the first mass-produced microcomputers. Apple went public in 1980 to instant financial success. The company developed computers featuring innovative graphical user inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin (operating System)
Darwin is an open-source Unix operating system first released by Apple Inc. in 2000. It is composed of code derived from NeXTSTEP, BSD, Mach, and other free software projects' code, as well as code developed by Apple. Darwin forms the Unix-based core set of components upon which macOS (previously OS X and Mac OS X), iOS, watchOS, tvOS, iPadOS and bridgeOS are based. It is mostly POSIX-compatible, but has never, by itself, been certified as compatible with any version of POSIX. Starting with Leopard, macOS has been certified as compatible with the Single UNIX Specification version 3 (SUSv3). History The heritage of Darwin began with Unix derivatives supplemented by aspects of NeXT's NeXTSTEP operating system (later, since version 4.0, known as OPENSTEP), first released in 1989. After Apple bought NeXT in 1996, it announced it would base its next operating system on OPENSTEP. This was developed into Rhapsody in 1997, Mac OS X Server 1.0 in 1999, Mac OS X Public Beta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MacOS
macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and laptop computers it is the second most widely used desktop OS, after Microsoft Windows and ahead of ChromeOS. macOS succeeded the classic Mac OS, a Mac operating system with nine releases from 1984 to 1999. During this time, Apple cofounder Steve Jobs had left Apple and started another company, NeXT, developing the NeXTSTEP platform that would later be acquired by Apple to form the basis of macOS. The first desktop version, Mac OS X 10.0, was released in March 2001, with its first update, 10.1, arriving later that year. All releases from Mac OS X 10.5 Leopard and after are UNIX 03 certified, with an exception for OS X 10.7 Lion. Apple's other operating systems (iOS, iPadOS, watchOS, tvOS, audioOS) are derivatives of macOS. A pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPadOS
iPadOS is a mobile operating system developed by Apple Inc. for its iPad line of tablet computers. It is a rebranded variant of iOS, the operating system used by Apple's iPhones, renamed to reflect the diverging features of the two product lines, particularly the iPad's multitasking capabilities. It was introduced as iPadOS 13 in 2019, reflecting its status as the successor to iOS 12 for the iPad, at the company's 2019 Worldwide Developers Conference. iPadOS was released to the public on September 24, 2019. The current public release is iPadOS 16.2, released on December 13, 2022. History The first iPad was released on January 10th, 2010 and ran iPhone OS 3.2, which added support for the larger device to the operating system, previously only used on the iPhone and its smaller counterpart, the iPod Touch. This shared operating system was rebranded as " iOS" with the release of iOS 4. The operating system initially had rough feature parity running on the iPhone, iPo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARM Architecture
ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of reduced instruction set computer (RISC) instruction set architectures for computer processors, configured for various environments. Arm Ltd. develops the architectures and licenses them to other companies, who design their own products that implement one or more of those architectures, including system on a chip (SoC) and system on module (SOM) designs, that incorporate different components such as memory, interfaces, and radios. It also designs cores that implement these instruction set architectures and licenses these designs to many companies that incorporate those core designs into their own products. There have been several generations of the ARM design. The original ARM1 used a 32-bit internal structure but had a 26-bit address space that limited it to 64 MB of main memory. This limitation was removed in the ARMv3 series, which h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprietary Software
Proprietary software is software that is deemed within the free and open-source software to be non-free because its creator, publisher, or other rightsholder or rightsholder partner exercises a legal monopoly afforded by modern copyright and intellectual property law to exclude the recipient from freely sharing the software or modifying it, and—in some cases, as is the case with some patent-encumbered and EULA-bound software—from making use of the software on their own, thereby restricting his or her freedoms. It is often contrasted with open-source or free software. For this reason, it is also known as non-free software or closed-source software. Types Origin Until the late 1960s computers—large and expensive mainframe computers, machines in specially air-conditioned computer rooms—were usually leased to customers rather than sold. Service and all software available were usually supplied by manufacturers without separate charge until 1969. Computer vend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BootX (Apple)
BootX is a software-based bootloader designed and developed by Apple Inc. for use on the company's Macintosh computer range. BootX is used to prepare the computer for use, by loading all required device drivers and then starting-up Mac OS X by booting the kernel on all PowerPC Macintoshes running the Mac OS X 10.2 operating system or later versions. Using BootROM, a read-only memory (ROM) computer chip containing OpenFirmware, a graphical bootsplash is shown briefly on all compatible Macintosh computers as a grey Apple logo with a spinning cursor that appears during the startup sequence. The program is freely available as part of the Darwin operating system under the open-source Apple Public Source License. BootX was superseded by another nearly identical bootloader named boot.efi and an Extensible Firmware Interface ROM on the release of the Intel-based Mac. History Older Macintoshes dating from 1983 until 1998 utilized a basic bootloader; the bootloader was solely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unified Extensible Firmware Interface
UEFI (Unified Extensible Firmware Interface) is a set of specifications written by the UEFI Forum. They define the architecture of the platform firmware used for booting and its interface for interaction with the operating system. Examples of firmware that implement these specifications are AMI Aptio, Phoenix SecureCore, TianoCore EDK II and InsydeH2O. UEFI replaces the BIOS which was present in the boot ROM of all personal computers that are IBM PC-compatible, although it can provide backwards compatibility with the BIOS using CSM booting. Intel developed the original ''Extensible Firmware Interface'' (''EFI'') specifications. Some of the EFI's practices and data formats mirror those of Microsoft Windows. In 2005, UEFI deprecated EFI 1.10 (the final release of EFI). UEFI is independent of platform and programming language, but C is used for the reference implementation TianoCore EDKII. History The original motivation for EFI came during early development of the first In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power On Self Test
A power-on self-test (POST) is a process performed by firmware or software routines immediately after a computer or other digital electronic device is powered on. This article mainly deals with POSTs on personal computers, but many other embedded systems such as those in major appliances, avionics, communications, or medical equipment also have self-test routines which are automatically invoked at power-on. The results of the POST may be displayed on a panel that is part of the device, output to an external device, or stored for future retrieval by a diagnostic tool. Since a self-test might detect that the system's usual human-readable display is non-functional, an indicator lamp or a speaker may be provided to show error codes as a sequence of flashes or beeps. In addition to running tests, the POST process may also set the initial state of the device from firmware. In the case of a computer, the POST routines are part of a device's pre-boot sequence; if they complete success ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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