Programmer's key: Difference between revisions

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{{Short description|Macintosh System Switch}}

[[Image:Macintosh Classic II Left Side Reset Interrupt Switch.jpg|thumb|250px|The interrupt button/programmer's key protruding from the air vent on the left hand side of an Apple [[Macintosh Classic II]] computer (left with a circle symbol)]]

{{refimprove|date=September 2018}}

[[Image:Macintosh Classic II Left Side Reset Interrupt Switch.jpg|thumb|250px|The interrupt button/programmer's key protruding from the air vent on the left -hand side of an Apple [[Macintosh Classic II]] computer (on the left, withabove athe circlecircular symbol)]]

The '''Programmer's Key''', or ''interrupt button'', is a button or switch on a [[computer]] which causes an [[asynchronous]] [[interrupt]] request (IRQ) to be sent to the [[central processing unit|processor]]. If a [[debugger]] is installed on the machine, it is activated when the interrupt request is processed, allowing the user to view and usually modify the computer's internal memory. The interrupt is of highest priority, allowing debugging of [[interrupt handler]]s. This is quite useful in [[debugging]] software, which is why it gets its name.

ThisThe term'''programmer's key''', or ''interrupt button'', is useda chieflybutton amongor switch on [[Classic Mac OS]]-era [[Apple Macintosh|Macintosh]] programmerssystems, perhapswhich becausejumps theto Maca hardware[[machine oncecode supportedmonitor]]. thisThe functionsymbol on the button is ⎉: {{unichar|2389|html=}}. On most [[68000 family]] based Macintosh computers, an interrupt request can also be sent by holding down the ''command'' key and strikingpressing the ''power'' key on the keyboard. This effect is also simulated by the 68000 environment of the [[Mac OS nanokernel]] on PowerPC machines and the [[Classic environment]].

The "key" need not always be a button or a switch. On some computers, it is a pinhole into which a straightened paperclip must be inserted (to prevent accidental activation).

Pressing the interrupt button during startup crashes the system and displays the [[Sad Mac]].

This term is used chiefly among [[Apple Macintosh|Macintosh]] programmers, perhaps because the Mac hardware once supported this function. On most [[68000 family]] based Macintosh computers, an interrupt request can also be sent by holding down the ''command'' key and striking the ''power'' key on the keyboard. This effect is also simulated by the 68000 environment of the [[Mac OS nanokernel]] on PowerPC machines and the [[Classic environment]].

A plastic insert came with [[Macintosh 128K]], [[Macintosh 512K]], [[Macintosh Plus]], and [[Macintosh SE]] computers that could be attached to the exterior of the case and was used to press an interrupt button located on the motherboard.<ref>{{cite web |url=https://www.hardwaresecrets.com/inside-the-macintosh-plus/4/ |title=Inside the Macintosh Plus |first=Gabriel |last=Torres |date=January 2, 2013 |website=Hardware Secrets |accessdate=September 18, 2018}}</ref><ref>{{cite web |url=https://www.macobserver.com/tmo/article/happy-birthday-mac-how-to-recover-from-the-dreaded-bomb-box-error-message |title=Happy Birthday, Mac - How to Recover From the Dreaded Bomb Box Error Message |first=Sandro |last=Cuccia |date=January 25, 2014 |website=The Mac Observer |accessdate=September 18, 2018}}</ref>

Modern Mac hardware no longer includes the interrupt button, as the Mac OS X operating system has integrated debugging options. In addition, Mac OS X's protected memory blocks direct patching of system memory (in order to better secure the system).

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* [[Interrupt]]

* [[Context switch]]

* [[MacsBug]]

[[Category:Computing input devices]]

==References==

{{reflist}}

==External links==

* {{webarchive |url=https://web.archive.org/web/20040620191308if_/http://developer.apple.com/technotes/tn/tn1136.html |date=June 20, 2004 |title=MicroBug: The ROM Debugger - TN1136}}

{{DEFAULTSORT:Programmer's Key}}

[[Category:Debugging]]

[[Category:Interrupts]]

{{mac-stub}}