Why exactly could ISA devices not share IRQs?

It seems to me that if more than one device may raise the same IRQ, then the device #driver⁠s for those devices should all wake up and poll their devices to see which device needs attention.

In theory, this would work, just slower.

And yet, somehow, this is not what happens if two devices on an #ISA bus share the same #IRQ. Instead, the system hangs. Why is that?

#retrocomputing

Yes, the Apple II MouseCard IRQ Is Synced to the VBL

https://www.colino.net/wordpress/en/archives/2025/05/08/yes-the-apple-ii-mousecard-irq-is-synced-to-the-vbl/

#HackerNews #AppleII #MouseCard #VBL #IRQ #TechHistory #RetroComputing

Took a moment and fixed the issue with my crashing #Pentium 200MMX system. Now the #PicoGUS with #WP32 #McCake wavetable if running #MonkeyIsland they way it's supposed to run :-) There's also a #Vibra16 card in there, which is unused for this game.

The issue? #IRQ, obviously. The introduction of a SATA controller meant that IRQ 5 previously used by the PicoGUS was grabbed by the controller and the system died with playing audio.

Nice to know the tech skills of the #90s are still there.

And sorry about the video quality - I got all excited and didn't care.

https://photos.app.goo.gl/WRWPSZft9YgDyTuC6

#vintagecomputing #vintagegaming

… I have seen things you wouldn’t believe …

… ribbon cables for hard drives… Master/Slave #SCSI termination… (mind screams in rebellion)… the little switch boxes to hook your original #Nintendo console or #VIC20 to a TV and then get headaches from staring at the TV CRT too closely…. a VIC-20 cassette drive with a box of about 150+ unlabeled tapes… painstakingly typed in from the listings in #BYTE magazines… Taking low-density 3.5″ floppies, and drilling/punching a hole through to double your storage and make them “high-density”…. the squeal of a modem (and trying to get the #IRQ conflicts resolved via changing jumper switches)… attempting to connect to #Datapac to try and reach unknown systems, running a #BBS inside a #DOS box, on #386(SX) #Windows 3.0 machine, Setting up your own #UUCP #internet over #dialup…

All those moments will be lost in time, like tears in rain…

The clicking of an #IOMEGA #ZIP drive, whose time it was to die…

#IRQ 2-1 #JPN
FT
#AFCAsianCup

이라크가 일본을 잡고 16강 진출.

Found this at a local IT distributor today in their clearance rack….

#fastpage #edo #oldschoolit #realit #irq #hyptecaustralia #pcfixit #memories