How old is interrupt request (IRQ) technology?

Question

Doing a report on it, and I can't find date data anywhere! How old is IRQ technolgy (rough dates)?

What did computer do before interrupt requests existed? Just generate errors?

Before interrupts they used polling. – user207421 Feb 16 '14 at 20:55 — user207421, Feb 16 '14 at 20:55

score 1 · Answer 1 · answered Feb 22 '13 at 00:14

1

62 years.

According to: this site

I've been using interrupts on microcomputers (PCs) since their invention.

I'm not sure "just generate errors" is really the alternative to having support for interrupts. But I suppose in the specific case of a hw/sw interrupt being used for error trapping, yes that would be the alternative.

More broadly, interrupts allow for sharing of the CPU - multitasking, hardware interfacing, etc.

Hope that helps!

answered Feb 22 '13 at 00:14

Mark Stevens

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Wow. that is EXACTLY what I needed. Thanks for the link and info! – Bert Macky Feb 22 '13 at 19:53

score 0 · Answer 2 · edited May 23 '17 at 12:18

Interrupts are not only useful for errors. As the name suggests, they interrupt the processor's work. In essence, it is a processor event signal. In current processors they signal events ranging from errors, devices that have something to say, programs that yield, memory events...

Before the advent of interrupts there was just no way to interrupt the processor. It just kept on executing the program instructions in the order they appeared. Such processors had special blocking instructions for, for example, reading from an external storage device (disk, tape). Keyboards and such random interval devices, if they existed, were polled through a special instruction to see whether any key was pressed.

Errors, when they occurred, just resulted in unpredictable program behavior. There were not really that many handleable errors that could occur in those old processors. Mainly division by zero, which could be avoided by careful programming.

In this link the author tells his experiences with interrupt-like constructs, the first of which he had seen in 1957, 56 years ago. The link that was also posted by Mark Stevens cites 1951, 62 years ago.

If you're interested in the internals of computers and processors, I can recommend the book Computer Organization by Carl Hamacher, Zvonko Vranesic and Safwat Zaky.

score 0 · Answer 3 · answered Feb 16 '14 at 20:02

Check this recent article about the history of interrupts in computers going back to their very invention. The short article also features a video and references all the available material I could find on the topic. http://virtualirfan.com/history-of-interrupts

Fascinating history of interrupts especially the bit about how Djikstra was freaked out 'bout them.

How old is interrupt request (IRQ) technology?

3 Answers3