Interrupt 19 capture bios option

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What does it mean to enable interrupt 19 capture. The help text for this option reads: enable to allow the option ROMs to trap the interrupt 19.

Semi relevant: Asus WS motherboard (intel z97).

Ярослав Рахматуллин

Posted 2015-11-13T22:29:39.723

Reputation: 9 076

Answers

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This is used by certain devices to intercept the normal boot process.

INT 19h (see Wikipedia) is a low-level system command normally used just after POST to boot the operating system. In typical end-user configurations outside of a business environment this setting may be ignored as it likely has no effect on your system.

Peripheral devices providing option ROMs such as network interface cards (PXE) or RAID storage controllers may intercept this command to run code that is required to set up the boot media (e.g RAID) before handing it over to the OS.

bwDraco

Posted 2015-11-13T22:29:39.723

Reputation: 41 701

Hey, thanks for your good explanation! Finally... Most aren't really helpful in any way - especially most often those super "brainy" (f***) written MB manuals - in English already, not translated further - which should explain all available settings and options and tell clearly what they are (for)/do so that one knows afterwards where to set what why and what for. I certainly already knew this setting affects Option ROMs as in my known MBs this setting/description are a little bit different and say so but thanks to your post I even learned some fundamentals about this too - this is very sweet! – Silvan Hofer – 2019-09-16T04:56:29.123

I really don't expect MB Manuals to give deeper technical information like this as I think most people wouldn't be interested / not understand such anyway and also, those details aren't relevant for knowing what a setting is for/does and what to set therefore. But written half-hearted, unenthusiastic, uncaring such absolutely useless sh*t like "Enables or disables Option XYZ" which I saw and see very often is just...?!? Wasted ink and paper for nonsense! Then they'd better let such be and leave it away totally (which I saw and see regularly too, sadly) and instead write tech details elsewhere! – Silvan Hofer – 2019-09-16T05:25:51.033

But still, one main question or THE main question for me about this remains just unanswered (to say: "Enable/Disable" is sure clear but as I know this setting from my current and previous boards, it's description/options are different: "BIOS reaction on INT19 trapping by Option ROM: IMMEDIATE - execute the trap right away; POSTPONED - execute the trap during legacy boot"): So, what does changing this setting result here in the end? I mean, the description is not bad and it exactly tells what it does. But I have no idea what this means to me, what happens/changes, what's the effect finally?!? – Silvan Hofer – 2019-09-16T05:46:06.127

Ah, and does this have any context with Secure Boot (no idea what does "legacy boot" mean)? But it's nice, a description which really absolutely and exactly tells what the setting does/is for but nevertheless, not any kind of idea what this means at the end, what this changes/affects, what's the final result/consequences when changing from one to the other. And about exactly those bios settings which are not or not well described or still not clear like this one you don't find much useful information or explanation by searching online. only questions or similar/same description of the manual. – Silvan Hofer – 2019-09-16T06:11:03.930