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System Management Mode
System Management Mode (SMM, sometimes called ring −2 in reference to protection rings) is an operating mode of x86 central processor units (CPUs) in which all normal execution, including the operating system, is suspended. An alternate software system which usually resides in the computer's firmware, or a hardware-assisted debugger, is then executed with high privileges. It was first released with the Intel 386SL. While initially special SL versions were required for SMM, Intel incorporated SMM in its mainline 486 and Pentium processors in 1993. AMD implemented Intel's SMM with the Am386 processors in 1991. It is available in all later microprocessors in the x86 architecture. Some ARM processors also include the Management Mode, for the system firmware (such as UEFI). Operation SMM is a special-purpose operating mode provided for handling system-wide functions like power management, system hardware control, or proprietary OEM designed code. It is intended for us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protection Ring
In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (by improving fault tolerance) and malicious behavior (by providing computer security). Computer operating systems provide different levels of access to resources. A protection ring is one of two or more hierarchical ''levels'' or ''layers'' of privilege within the architecture of a computer system. This is generally hardware-enforced by some CPU architectures that provide different CPU modes at the hardware or microcode level. Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered zero) to least privileged (least trusted, usually with the highest ring number). Ring 0 is the level with the most privileges and allows direct interaction with the physical hardware such as certain CPU functionality and chips on the motherboard. Special call gates between rings are provided to allow an outer ring to acce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Configuration And Power Interface
Advanced Configuration and Power Interface (ACPI) is an open standard that operating systems can use to discover and configure computer hardware components, to perform power management (e.g. putting unused hardware components to sleep), auto configuration (e.g. Plug and Play and hot swapping), and status monitoring. First released in December 1996, ACPI aims to replace Advanced Power Management (APM), the MultiProcessor Specification, and the Plug and Play BIOS (PnP) Specification. ACPI brings power management under the control of the operating system, as opposed to the previous BIOS-centric system that relied on platform-specific firmware to determine power management and configuration policies. The specification is central to the Operating System-directed configuration and Power Management (OSPM) system. ACPI defines hardware abstraction interfaces between the device's firmware (e.g. BIOS, UEFI), the computer hardware components, and the operating systems. Internally, ACPI a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NSA ANT Catalog
The ANT catalog (or TAO catalog) is a classified product catalog by the U.S. National Security Agency (NSA) of which the version written in 2008–2009 was published by German news magazine ''Der Spiegel'' in December 2013. Forty-nine catalog pages with pictures, diagrams and descriptions of espionage devices and spying software were published. The items are available to the Tailored Access Operations unit and are mostly targeted at products from US companies such as Apple, Cisco and Dell. The source is believed to be someone different than Edward Snowden, who is largely responsible for the global surveillance disclosures since 2013. Companies whose products could be compromised have denied any collaboration with the NSA in developing these capabilities. In 2014, a project was started to implement the capabilities from the ANT catalog as open-source hardware and software. Background The Tailored Access Operations unit has existed since the late 90s. Its mission is to coll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Software
System software is software designed to provide a platform for other software. Examples of system software include operating systems (OS) like macOS, Linux, Android and Microsoft Windows, computational science software, game engines, search engines, industrial automation, and software as a service applications. Application software is software that allows users to do user-oriented tasks such as create text documents, play or develop games, create presentations, listen to music, draw pictures or browse the web. In the late 1940s, the early days of computing, most application software was custom-written by computer users to fit their specific hardware and requirements. System software was usually supplied by the manufacturer of the computer hardware and was intended to be used by most or all users of that system. Many operating systems come pre-packaged with basic application software. Such software is not considered system software when it can be uninstalled without affecting th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rootkit
A rootkit is a collection of computer software, typically malicious, designed to enable access to a computer or an area of its software that is not otherwise allowed (for example, to an unauthorized user) and often masks its existence or the existence of other software. The term ''rootkit'' is a compound of "root" (the traditional name of the privileged account on Unix-like operating systems) and the word "kit" (which refers to the software components that implement the tool). The term "rootkit" has negative connotations through its association with malware. Rootkit installation can be automated, or an attacker can install it after having obtained root or administrator access. Obtaining this access is a result of direct attack on a system, i.e. exploiting a vulnerability (such as privilege escalation) or a password (obtained by cracking or social engineering tactics like "phishing"). Once installed, it becomes possible to hide the intrusion as well as to maintain privileged ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UEFI Platform Initialization
The Platform Initialization Specification (PI Specification) is a specification published by the Unified EFI Forum that describes the internal interfaces between different parts of computer platform firmware. This allows for more interoperability between firmware components from different sources. This specification is normally, but not by requirement, used in conjunction with the UEFI 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 ... specification. Current version Platform Initialization Specification 1.7, Released January 2019. Contents As of version 1.3, the PI specification contains five volumes: * Volume 1: Pre-EFI Initialization Core Interface * Volume 2: Driver Execution Environment Core Interface * Volume 3: Shared Architectural Elements * Volume 4: System Managemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thunderbolt (interface)
Thunderbolt is the brand name of a hardware interface for the connection of external peripherals to a computer. It has been developed by Intel, in collaboration with Apple. It was initially marketed under the name Light Peak, and first sold as part of an end-user product on 24 February 2011. Thunderbolt combines PCI Express (PCIe) and DisplayPort (DP) into two serial signals, and additionally provides DC power, all in one cable. Up to six peripherals may be supported by one connector through various topologies. Thunderbolt 1 and 2 use the same connector as Mini DisplayPort (MDP), whereas Thunderbolt 3 and 4 reuse the USB-C connector from USB. Description Thunderbolt controllers multiplex one or more individual data lanes from connected PCIe and DisplayPort devices for transmission via two duplex Thunderbolt lanes, then de-multiplex them for use by PCIe and DisplayPort devices on the other end. A single Thunderbolt port supports up to six Thunderbolt devices via hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trusted Platform Module
Trusted Platform Module (TPM, also known as ISO/IEC 11889) is an international standard for a secure cryptoprocessor, a dedicated microcontroller designed to secure hardware through integrated cryptographic keys. The term can also refer to a chip conforming to the standard. TPM is used for digital rights management (DRM), Windows Defender, Windows Domain logon, protection and enforcement of software licenses, and prevention of cheating in online games. One of Windows 11's system requirements is TPM 2.0. Microsoft has stated that this is to help increase security against firmware and ransomware attacks. History Trusted Platform Module (TPM) was conceived by a computer industry consortium called Trusted Computing Group (TCG). It evolved into ''TPM Main Specification Version 1.2'' which was standardized by International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) in 2009 as ISO/IEC 11889:2009. ''TPM Main Specification Version 1. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PS/2 Port
The PS/2 port is a 6-pin mini-DIN connector used for connecting keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. The PS/2 mouse connector generally replaced the older DE-9 RS-232 "serial mouse" connector, while the PS/2 keyboard connector replaced the larger 5-pin/180° DIN connector used in the IBM PC/AT design. The PS/2 keyboard port is electrically and logically identical to the IBM AT keyboard port, differing only in the type of electrical connector used. The PS/2 platform introduced a second port with the same design as the keyboard port for use to connect a mouse; thus the PS/2-style keyboard and mouse interfaces are electrically similar and employ the same communication protocol. However, unlike the otherwise similar Apple Desktop Bus connector used by Apple, a given system's keyboard and mouse port may not be interchangeable since the two devices use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embedded Controller
An Embedded Controller (EC) is a microcontroller in computers that handles various system tasks. Now it is usually merged with Super I/O, especially on mobile platforms (such as laptop). Tasks An embedded controller can have the following tasks: *Receiving and processing signals from the keyboardhttp://www.computer-engineering.org/ps2keyboard/ and the touchpad (including touchpad disable) *Other buttons and switches (e.g., power button, laptop lid switch (received from hall sensor)) *Controlling access to the A20 line *Thermal measurement (CPU, GPU, Motherboard) and response including fan control, CPU and GPU throttling, and emergency shutdown in response to rising temperatures *Controlling indicator LEDs (e.g. caps lock, scroll lock, num lock, battery, ac, power, wireless LAN, sleep) *Managing the battery charger and the battery *Allowing remote diagnostics and remediation over the network *Performing software-requested CPU reset *Controlling the watchdog timer *System Mana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super I/O
Super I/O is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a variety of low- bandwidth devices. Now it is mostly merged with EC. The functions below are usually provided by the super I/O if they are on the motherboard: * A floppy-disk controller * An IEEE 1284-compatible parallel port (commonly used for printers) * One or more 16C550-compatible serial port UARTs * Keyboard controller for PS/2 keyboard and/or mouse Most Super I/O chips include some additional low-speed devices, such as: * Temperature, voltage, and fan speed interface * Thermal Zone * Chassis intrusion detection * Mainboard power management * LED management * PWM fan speed control * An IrDA Port controller * A game port (not provided by recent super I/O chips anymore because Windows XP is the last Windows OS to support a game p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LPCIO
The Low Pin Count (LPC) bus is a computer bus used on IBM-compatible personal computers to connect low-bandwidth devices to the CPU, such as the BIOS ROM (BIOS ROM was moved to the Serial Peripheral Interface (SPI) bus in 2006), "legacy" I/O devices (integrated into Super I/O, Embedded Controller or IPMI chip), and Trusted Platform Module (TPM). "Legacy" I/O devices usually include serial and parallel ports, PS/2 keyboard, PS/2 mouse, and floppy disk controller. Most PC motherboards with an LPC bus have either a Platform Controller Hub (PCH) or a southbridge chip, which acts as the host and controls the LPC bus. All other devices connected to the physical wires of the LPC bus are peripherals. Overview The LPC bus was introduced by Intel in 1998 as a software-compatible substitute for the Industry Standard Architecture (ISA) bus. It resembles ISA to software, although physically it is quite different. The ISA bus has a 16-bit data bus and a 24-bit address bus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
