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BIOS Boot Specification
An Option ROM for the PC platform (i.e. the IBM PC and derived successor computer systems) is a piece of firmware that resides in ROM on an expansion card (or stored along with the main system BIOS), which gets executed to initialize the device and (optionally) add support for the device to the BIOS. In its usual use, it is essentially a driver that interfaces between the BIOS API and hardware. Technically, an option ROM is firmware that is executed by the BIOS after POST (the testing and initialization of basic system hardware) and before the BIOS boot process, gaining complete control of the system and being generally unrestricted in what it can do. The BIOS relies on each option ROM to return control to the BIOS so that it can either call the next option ROM or commence the boot process. For this reason, it is possible (but not usual) for an option ROM to keep control and preempt the BIOS boot process. The BIOS (at least as originally designed by IBM) generally scans for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM PC Compatible
IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones. The term "IBM PC compatible" is now a historical description only, since IBM no longer sells personal computers after it sold its personal computer division in 2005 to Chinese technology company Lenovo. The designation "PC", as used in much of personal computer history, has not meant "personal computer" generally, but rather an x86 computer capable of running the same software that a contemporary IBM PC could. The term was initially in contrast to the variety of home computer systems available in the early 1980s, such as the Apple II, TRS-80, and Commodore 64. Later, the term was primarily used in contrast to Apple's Macintosh computers. These "clones" duplicated almost all the significant features of the original IBM PC architectures. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Program Counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is a processor register that indicates where a computer is in its program sequence. Usually, the PC is incremented after fetching an instruction, and holds the memory address of (" points to") the next instruction that would be executed. Processors usually fetch instructions sequentially from memory, but ''control transfer'' instructions change the sequence by placing a new value in the PC. These include branches (sometimes called jumps), subroutine calls, and returns. A transfer that is conditional on the truth of some assertion lets the computer follow a different sequence under different conditions. A branch provides that the next instruction is fetched from elsewhere in memory. A subroutine call not only branches but saves the preced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secure Boot
UEFI (Unified Extensible Firmware Interface) is a set of Specification (technical standard), specifications written by the UEFI Forum. They define the Software architecture, architecture of the platform firmware used for booting and its Interface (computer science), interface for interaction with the operating system. Examples of firmware that implement these specifications are AMI Aptio, Phoenix Technologies, 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, IBM PC-compatible, although it can provide Backward compatibility, backwards compatibility with the BIOS using UEFI#CSM booting, 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 progra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compatibility Support Module
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 Int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UEFI GOP
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of around 74.99%. macOS by Apple Inc. is in second place (14.84%), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video BIOS
Video BIOS is the BIOS of a graphics card in a (usually IBM PC-derived) computer. It initializes the graphics card at the computer's boot time. It also implements INT 10h interrupt and VESA BIOS Extensions (VBE) for basic text and videomode output before a specific video driver is loaded. In UEFI 2.x systems, the INT 10h and the VBE are replaced by the UEFI GOP. Much the way the system BIOS provides a set of functions that are used by software programs to access the system hardware, the video BIOS provides a set of video-related functions that are used by programs to access the video hardware as well as storing vendor-specific settings such as card name, clock frequencies, VRAM types & voltages. The video BIOS interfaces software to the video chipset in the same way that the system BIOS does for the system chipset. The ROM also contained a code page 437, basic font set to upload to the video adapter font RAM, if the video card did not contain a font ROM with this font set instead. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassette BASIC
The IBM Personal Computer Basic, commonly shortened to IBM BASIC, is a programming language first released by IBM with the IBM Personal Computer, Model 5150 (IBM PC) in 1981. IBM released four different versions of the Microsoft BASIC interpreter, licensed from Microsoft for the PC and PCjr. They are known as Cassette BASIC, Disk BASIC, Advanced BASIC (BASICA), and Cartridge BASIC. Versions of Disk BASIC and Advanced BASIC were included with IBM PC DOS up to PC DOS 4. In addition to the features of an ANSI standard BASIC, the IBM versions offered support for the graphics and sound hardware of the IBM PC line. Source code could be typed in with a full-screen editor, and very limited facilities were provided for rudimentary program debugging. IBM also released a version of the Microsoft BASIC compiler for the PC, concurrently with the release of PC DOS 1.10 in 1982. Background IBM licensed Microsoft BASIC for the IBM Personal Computer, despite already having its own version of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Booting
Network booting, shortened netboot, is the process of booting a computer from a network rather than a local drive. This method of booting can be used by routers, diskless workstations and centrally managed computers (thin clients) such as public computers at libraries and schools. Network booting can be used to centralize management of disk storage, which supporters claim can result in reduced capital and maintenance costs. It can also be used in cluster computing, in which nodes may not have local disks. In the late 1980s/early 1990s, network boot was used to save the expense of a disk drive, because a decently sized harddisk would still cost thousands of dollars, often equaling the price of the CPU. Hardware support Contemporary desktop personal computers generally provide an option to boot from the network in their BIOS/UEFI via the Preboot Execution Environment (PXE). Post-1998 PowerPC ( G3 G5) Mac systems can also boot from their New World ROM firmware to a network dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AHCI
The Advanced Host Controller Interface (AHCI) is a technical standard defined by Intel that specifies the Hardware register, register-level interface of Serial ATA (SATA) host controllers in a non-implementation-specific manner in its Intel chips, motherboard chipsets. The specification describes a system memory structure for computer hardware vendors to exchange data between host system computer memory, memory and attached computer storage device, storage devices. AHCI gives software developers and hardware designers a standard method for detecting, configuring, and programming SATA/AHCI adapters. AHCI is separate from the SATA 3 Gbit/s standard, although it exposes SATA's advanced capabilities (such as hot swapping and Native Command Queuing, native command queuing) such that host systems can utilize them. For modern Solid-state drive, solid state drives, the interface has been superseded by NVM Express, NVMe. The current version of the specification is 1.3.1. Operating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
INT 13h
INT 13h is shorthand for BIOS interrupt call 13 hex, the 20th interrupt vector in an x86-based (IBM PC-descended) computer system. The BIOS typically sets up a real mode interrupt handler at this vector that provides sector-based hard disk and floppy disk read and write services using cylinder-head-sector (CHS) addressing. Modern PC BIOSes also include INT 13h extension functions, originated by IBM and Microsoft in 1992, that provide those same disk access services using 64-bit LBA addressing; with minor additions, these were quasi-standardized by Phoenix Technologies and others as the EDD (Enhanced Disk Drive) BIOS extensions. INT is an x86 instruction that triggers a software interrupt, and 13hex is the interrupt number (as a hexadecimal value) being called. Modern computers come with both BIOS INT 13h and UEFI functionality that provides the same services and more, with the exception of UEFI Class 3 that completely removes CSM thus lacks INT 13h and other interrupts. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI
Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interfaces. The SCSI standard defines command sets for specific peripheral device types; the presence of "unknown" as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements. The initial Parallel SCSI was most commonly used for hard disk drives and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices. The ancestral SCSI standard, X3.131-1986, generally referred to as SCSI-1, was published by the X3T9 technical committee of the American National Standards Institute (ANSI) in 1986. SCSI-2 was published in August 1990 as X3.T9.2/86-109 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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