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SubjectRe: [ANNOUNCE] New PC-Speaker driver
On Thursday 15 August 2002 12:57, Alan Cox wrote:
> There are easier equivalent ways to accurately measure the IRQ
> behaviour. Flip the state of a parallel port pin when you mask
> interrupts. You can even slap an oscilloscope on it that way

Right, I'll just go get my oscilloscope now...

In fact I relied on the technique you mentioned a great deal when
I was doing realtime work with PCs. With a multi-trace digital
scope the effect is something like a poor-man's logic analyser
with a resolution of 10 us or so.

Another technique I can recommend highly is panicking by halting
in a tight loop with the speaker set to emit some tone. It may
be annoying for the guy at the next bench but in some code, such
as transitioning to/from virtual86 mode, there aren't a lot of

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