"Hard reset" redirects here. For the video game, see Hard Reset. For process of restoring the software on device to new-as-from-the-factory, see factory reset.
A hardware reset or hard reset of a computer system is a hardware operation that re-initializes the core hardware components of the system, thus ending all current software operations in the system. This is typically, but not always, followed by booting of the system into firmware that re-initializes the rest of the system, and restarts the operating system.
Hardware resets are an essential part of the power-on process, but may also be triggered without power cycling the system by direct user intervention via a physical reset button, watchdog timers, or by software intervention that, as its last action, activates the hardware reset line (e.g, in a fatal error where the computer crashes).
User initiated hard resets can be used to reset the device if the software hangs, crashes, or is otherwise unresponsive. However, data may become corrupted if this occurs.[1] Generally, a hard reset is initiated by pressing a dedicated reset button, or holding a combination of buttons on some mobile devices.[2][3] Devices may not have a dedicated Reset button, but have the user hold the power button to cut power, which the user can then turn the computer back on.[4] On some systems (e.g, the PlayStation 2 video game console), pressing and releasing the power button initiates a hard reset, and holding the button turns the system off.
The 8086 microprocessors provide RESET pin that is used to do the hardware reset. When a HIGH is applied to the pin, the CPU immediately stops, and sets the major registers to these values:
The CPU uses the values of CS and IP registers to find the location of the next instruction to execute. Location of next instruction is calculated using this simple equation:
Location of next instruction = (CS<<4) + (IP)
This implies that after the hardware reset, the CPU will start execution at the physical address 0xFFFF0. In IBM PC compatible computers, This address maps to BIOSROM. The memory word at 0xFFFF0 usually contains a JMP instruction that redirects the CPU to execute the initialization code of BIOS. This JMP instruction is absolutely the first instruction executed after the reset.[5]
Hardware reset in later x86 CPUsedit
Later x86 processors reset the CS and IP registers similarly, refer to Reset vector.
hardware, reset, hard, reset, redirects, here, video, game, hard, reset, process, restoring, software, device, from, factory, factory, reset, been, suggested, that, this, article, merged, with, reset, computing, discuss, proposed, since, february, 2024, this, . Hard reset redirects here For the video game see Hard Reset For process of restoring the software on device to new as from the factory see factory reset It has been suggested that this article be merged with Reset computing Discuss Proposed since February 2024 This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Hardware reset news newspapers books scholar JSTOR February 2023 Learn how and when to remove this message A hardware reset or hard reset of a computer system is a hardware operation that re initializes the core hardware components of the system thus ending all current software operations in the system This is typically but not always followed by booting of the system into firmware that re initializes the rest of the system and restarts the operating system Hardware resets are an essential part of the power on process but may also be triggered without power cycling the system by direct user intervention via a physical reset button watchdog timers or by software intervention that as its last action activates the hardware reset line e g in a fatal error where the computer crashes User initiated hard resets can be used to reset the device if the software hangs crashes or is otherwise unresponsive However data may become corrupted if this occurs 1 Generally a hard reset is initiated by pressing a dedicated reset button or holding a combination of buttons on some mobile devices 2 3 Devices may not have a dedicated Reset button but have the user hold the power button to cut power which the user can then turn the computer back on 4 On some systems e g the PlayStation 2 video game console pressing and releasing the power button initiates a hard reset and holding the button turns the system off Contents 1 Hardware reset in 80x86 IBM PC 2 Hardware reset in later x86 CPUs 3 See also 4 ReferencesHardware reset in 80x86 IBM PC editThe 8086 microprocessors provide RESET pin that is used to do the hardware reset When a HIGH is applied to the pin the CPU immediately stops and sets the major registers to these values Register Value CS Code Segment 0xFFFF DS Data Segment 0x0000 ES Extra Data Segment 0x0000 SS Stack Segment 0x0000 IP Instruction Pointer 0x0000 The CPU uses the values of CS and IP registers to find the location of the next instruction to execute Location of next instruction is calculated using this simple equation Location of next instruction CS lt lt 4 IP This implies that after the hardware reset the CPU will start execution at the physical address 0xFFFF0 In IBM PC compatible computers This address maps to BIOS ROM The memory word at 0xFFFF0 usually contains a JMP instruction that redirects the CPU to execute the initialization code of BIOS This JMP instruction is absolutely the first instruction executed after the reset 5 Hardware reset in later x86 CPUs editLater x86 processors reset the CS and IP registers similarly refer to Reset vector See also editPower on reset Power on self test Reset vector Reboot computing References edit Fredman Josh Can a Forced Shutdown Ruin My Computer smallbusiness chron com Retrieved 2019 12 13 How to Hard Reset or Reboot any Android phone or tablet trendblog net 2015 07 20 Retrieved 2019 12 13 How to Force Restart the iPhone X When It s Acting Up Gadget Hacks 14 September 2017 Retrieved 2019 12 13 What is a Reset Button www computerhope com Retrieved 2019 12 13 The 80x86 IBM PC and Compatible Computers Volumes I amp II 4th Edition By Mohamed Ali Mazidi and Janice Gillispie Mazidi Section 9 1 Page 241 nbsp This computer science article is a stub You can help Wikipedia by expanding it vte nbsp This electronics related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Hardware reset amp oldid 1215511817, wikipedia, wiki, book, books, library,
