Santa sodium 2000 Superman's EFI system
The scalable firmware interface (English name Firmware Interface or EFI) is an upgrade solution for BIOS to replace BIOS in a future PC computer system that is dominated by a company developed by Intel. The rise of BIOS technology comes from the popularity of IBM PC/AT machines and the first "clone" PC developed and produced by Campbar. During the start of the PC, BIOS is responsible for initialized hardware, detecting hardware functions, and the responsibility of guiding the operating system. In the early days, BIOS also provided a set of service program for operating systems and applications. The BIOS program is stored in a memory that is not lost after power loss. The address of the first instruction of the processor during the system will be positioned in the memory of the BIOS, which is convenient for the initialization program to execute.
It is well known that Intel has led the PC technology trend based on the X86 series processor in the past two decades, her products such as CPU, chipset, etc. in PC The production line occupies the position of absolute leadership. Therefore, many people think that this move shows the ambition of Intel's desire to dye the firmware product market. In fact, EFI technology originated from the launch of the ITANIUM platform. The Anding processor is a 64 -bit new architecture that is completely different from the X86 series by Intel's high -end market investment in Intel's high -end market investment. In the era of the X86 series processors entering 32 -bit, due to compatibility reasons, the new processor (i80386) retained 16 -bit operating method (real mode). Way. Even in the strongest series of processors containing 64 -bit extension technology, the processor is still switched to 16 -bit real mode when the processor power is started. Intel attributed this situation to the development of BIOS technology slowly. Since the PC compatible machine manufacturer copies the first set of BIOS source programs through the net room, BIOS has more than ten years in the form of 16 -bit assembly code, register parameter calling, static links, and a fixed address of memory fixing below 1MB. Although many new elements have been added to the products due to the efforts of major BIOS manufacturers in recent years, such as PNP BIOS, ACPI, traditional USB device support, etc., the fundamental nature of BIOS has not changed. This forces Intel to consider adding a compatible mode that greatly reduces efficiency when developing and updated processors. Someone once made a metaphor: this is like Porsche's new -generation fully automatic stall sports car was put on a stingler in life.
. However, the Anding processor does not have such concerns. It is a new processor architecture. The interfaces between the system firmware and the operating system can be completely redefined. And this time, Intel defines it as a scalable, standardized firmware interface specification, unlike the fixed fixation of traditional BIOS, and lack of documents, it is completely based on experience and obscure agreed. The emergence of EFI -based system products has been five years since the emergence of EFI. Now, Intel has tried to promote technology to high -end servers to the PC product line with a more advantageous market share, and promised to be in 2006 in 2006 Will invest full -scale technical support.
The comparative EFI and BIOS
A significant difference is that EFI is modular, C language style parameter stack transmission method, and dynamic links. It is more easy to achieve, more fault -tolerant and error correction characteristics, shortening the time of system development. It runs in the 32 -bit or 64 -bit mode, and even in the future enhanced processor mode, breaks through the addressing capacity of the traditional 16 -bit code, and achieves the maximum addressing of the processor. It uses the form of EFI -driven to identify and operate hardware. Unlike BIOS using the method of mounting mode interruption, the hardware function is increased. The latter must place a 16 -bit code similar to the driver and place it in a fixed toast storage area to run the initialization part of this code. It will provide services to other programs with the interrupt vector of the mounting mode. For example, VGA graphics and text output interruptions (INT 10H), disk access interrupt services (INT 13H), and so on. Due to the limited storage space (128KB), BIOS has no power to put the size of the driving code that needs to be placed than the size of the space. In addition, BIOS's hardware service programs have existed in the form of 16 -digit code, which makes it difficult for the service system to access the enhanced mode. Therefore, the services provided by BIOS can only be used to use the operating system guidance program or MS-DOS operating system. The driver under the EFI system is not composed of code that can run directly on the CPU, but is written with EFI byte Code. This is a set of virtual machine instructions dedicated to EFI -driven. It must be explained under the EFI -driven operating environment (or DXE). This guarantees full downward compatibility. For example, an extended device with an EFI -driven device can be installed in a Anding processor system, or it can be installed in a new PC system that supports EFI systems that support EFI systems. And its EFI driver does not need to be rewritten. In this way, there is no need to consider the compatibility factors brought by the system upgrade. In addition, due to the simple EFI -driven development, all PC components providers can participate. The situation is very similar to the development model of modern operating systems. This development model has made Windows become powerful and superior in just two or three years. operating system. The EFI -based driver model can make the EFI system contact all the hardware functions. Before the operation of the operating system, browsing the Wanwei website is no longer a nightmare, and it is even very simple to implement. This is an impossible task for traditional BIOS systems. Adding a few simple USB device support to BIOS has made many BIOS designers suffering, not to mention addition to adding support for countless network hardware, but also Build a TCP/IP protocol stack in a 16 -bit mode out of thin air.
The people think that BIOS is just because of compatibility issues that are not leaving. The opponents believe that when the emergence of BIOS restricts the development of PC technology, someone must make necessary changes.
efi and operating system
efi is very similar to a low -level operating system, and has the ability to control all hardware resources. Many people feel that its continuous development may replace modern operating systems. In fact, when the founders of EFI were introduced in the first edition specification, EFI's capabilities were limited to not enough to threaten the dominance of the operating system. First of all, it is just the interface specification between hardware and pre -start software; second, no interrupt access mechanism is provided in the EFI environment, which means that each EFI driver must be checked in the hardware state by rotation, and it needs to be explained by explanation. The method is running, which is lower than the driving efficiency under the operating system; then, the EFI system does not provide complex memory protection functions. It only has a simple memory management mechanism. Specifically With the maximum addressing capacity, the memory is divided into a flat segment. All procedures have the permissions to access any position and do not provide real protection services. When all EFI components are loaded, the system can turn on an command to explain the environment similar to the operating system shell. Here, users can transfer any EFI applications. These programs can be hardware detection and removal software, guide management, settings Software, operating system guidance software and so on. In theory, there is no restriction on the functions of EFI applications. Anyone can write such software, and the effect is more gorgeous and more powerful than the software under MS-DOS. Once the guidance software will be controlled to the operating system, all the service code for guidance will stop work, and the service program of some operations can continue to work in order to facilitate the operating system that cannot find the driver of a specific device at a time. Can continue to be used.
is generally believed that EFI consists of the following parts:
1. Pre-EFI initialization module
2. EFI driver execution environment
3. EFI driver
4. Compatible support module (CSM)
5. EFI high -rise application
6. GUID disk partition
In implementation, the EFI initialization module and the driving execution environment are usually integrated in a readable memory. The pre-EFI initialization program was first executed when the system was turned on. It was responsible for the initial CPU, the initialization of the main bridge and memory, and then loaded the EFI driving execution environment (DXE). When DXE is loaded and runs, the system has the ability to enumerate and load other EFI drivers. In a PCI -based system, the EFI driver of each PCI bridge and PCI adapter will be loaded and initialized; at this time, the system will be enumerated and loaded with various bus and device drivers behind the bridge pickups and adapters. Until the driver of the last device was successfully loaded. Because of this, the EFI driver can be placed in any position of the system, as long as it can ensure that it can be accumulated correctly in order. For example, an ATAPI large -capacity storage adapter with a PCI bus interface, its EFI driver is generally placed in the expansion of the PCI specification that complies with the PCI specification. When the sub -device is used, the storage adapter is rotated correctly and loaded its driver. Some EFI drivers can also be placed in the EFI -specific partition of a disk, as long as these drivers are not necessary to load the driver of this disk. In the EFI specification, a GUID disk partition system (GPT) that breaks through the traditional MBR disk partition structure (GPT) is introduced. In the new structure, the number of partitions of the disk is no longer limited (under the MBR structure, only 4 main partitions can exist in 4 main partitions. ), And partition types will be represented by Guid. Among the many types of partitions, the EFI system partition can be accessible by the EFI system to store some drivers and applications. Many people worry that this will lead to new security factors, because EFI systems are more likely to be attacked by computer viruses than traditional BIOS. When some EFI drivers are destroyed, the system may face the situation that cannot be guided. In fact, the EFI driver dependent on the system guidance is usually not stored in the GUID partition of the EFI. Even if the driver in the partition is destroyed, it can be recovered in a simple way. This is with the driver under the operating system. The storage habits are the same. CSM is a special module in the X86 platform EFI system. It will provide system services similar to traditional BIOS for operating systems that do not have EFI guidance capabilities.
Intel is undoubtedly an active factor in promoting EFI. In recent years, due to the continuous deepening of the industry's understanding, more manufacturers are investing in this research. Some PC manufacturers, including Intel, have jointly established a joint scalable firmware interface forum, which will launch the first edition specification in the near future. This organization will take over the heavy responsibility of planning EFI development and interpret Intel's EFI framework as a specific implementation of this specification. In addition, major BIOS providers such as Phoenix, AMI, etc., were originally considered an obstacle to the development of EFI, and now continue to launch their own solutions. Analysts pointed out that this is because BIOS manufacturers have re-found market positions such as the Pre-EFI startup environment in the EFI architecture. This part of the market share will be unexpectedly in Intel's control.
The EFI system is ambiguous, depending on the occasion it uses.
1, EFI If the English name Firmware Interface is abbreviated, it is an extended firmware interface. The scalable firmware interface is an upgrade solution for BIOS in the future PC -like computer system launched by Intel.
2, EFI, if it is an abbreviation of the English name Fuel Injection (System), it refers to the electronic control fuel injection system, which is the main component of the automotive electronics engine. The electronic control fuel injection system is a system that uses various sensors to detect the various states of the engine. After the computer's judgment and calculation, the engine can obtain a systematic system of combustible mixed gas under different operating conditions.
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