About int08h


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  • Email stuart {at} int08h.com
  • Twitter @int08h

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All content on int08h is copyright © 2017-2018 int08h LLC and licensed under the Creative Commons Attribution-ShareAlike 4.0 License.

Stuart Stock writes on int08h in his personal capacity and is solely responsible for its content. The opinions expressed and statements made do not reflect the opinions, policies, or positions of any employers past or present.

WTF is an int08h?

It’s the old-school PC BIOS system timer interrupt. int is short for “interrupt” and 08h notates hex. Today one might write int0x08 instead. An Intel 852x programmable interval timer generated int08h ~18.2 times per second (every ~55 milliseconds).

“Well behaved” programs did not mess with int08h. Of course, not all programs (and programmers) were well behaved, thus those tempting fate by patching int08h could be quite interesting.

Okay, why 08 then?

Because the .com domain of my favorite PC interrupt, int13h, was already taken. Sadface.


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