Hardware bug
A hardware bug is a defect in the design, manufacture, or operation of computer hardware that causes incorrect operation. It is the counterpart of software bugs which refer to flaws in the code which operates computers, and is the original context in which "bug" was used to refer to such flaws. Intermediate between hardware and software are microcode and firmware which may also have such defects. In common usage, a bug is subtly different from a "glitch" which may be more transient than fundamental, and somewhat different from a "quirk" which may be considered useful or intrinsic. Errata (corrections to the documentation) may be published by the manufacturer to reflect such unintended operation, and "errata" is sometimes used as a term for the flaws themselves.
History
Unintended operation
Sometimes users take advantage of the unintended or undocumented operation of hardware to serve some purpose, in which case a flaw may be considered a feature. This gives rise to the often ironically employed acronym INABIAF, "It's Not A Bug It's A Feature".[1] For example, undocumented instructions, known as illegal opcodes, on the MOS Technology 6510 of the Commodore 64 and MOS Technology 6502 of the Apple II computers are sometimes utilized. Similarly programmers for the Amiga took advantage of the unintended operation of its coprocessors to produce new effects or optimizations.[citation needed]
Security vulnerabilities
Some flaws in hardware may lead to security vulnerabilities where memory protection or other features fail to work properly. Starting in 2017 a series of security vulnerabilities were found in the implementations of speculative execution on common processor architectures that allowed a violation of privilege level.
In 2019 researchers discovered that a manufacturer debugging mode, known as VISA, had an undocumented feature on Intel Platform Controller Hubs, known as chipsets, which made the mode accessible with a normal motherboard possibly leading to a security vulnerability.[2]
Pentium bugs
The Intel Pentium series of CPUs had two well-known bugs discovered after it was brought to market, the FDIV bug affecting floating point division which resulted in a recall in 1994, and the F00F bug discovered in 1997 which causes the processor to stop operating until rebooted.
See also
References
- ^ Nicholas Carr. "'IT'S NOT A BUG, IT'S A FEATURE.' TRITE—OR JUST RIGHT?". Wired.
- ^ Lucian Armasu (29 March 2019). "Intel Chipsets' Undocumented Feature Can Help Hackers Steal Data". Tom's Hardware.