Messages in this thread | | | Subject | Re: Black box flight recorder for Linux | From | Krzysztof Halasa <> | Date | Mon, 10 Apr 2006 21:44:06 +0200 |
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"linux-os \(Dick Johnson\)" <linux-os@analogic.com> writes:
> Further, in a boot where the BIOS needs to initialize hardware, > It will write all RAM before enabling NMI. This makes sure that > the parity bit(s) are set properly. Most BIOS will attempt to > preserve RAM on a 'warm' boot as a throw-back to the '286 days > with their above-1MB-memory-manager paged RAM because the > only way to get back from protected mode to 16-bit real mode > was a hardware reset.
I think there is no distinction WRT RAM test between cold and warm boot anymore. If the BIOS clears the RAM is, I think, determined by the "fast POST" option in BIOS setup (it always checks the size so some bytes will be changed anyway).
> When using a memory-manager like DOS's > HIMEM.SYS, you might actually be rebooting the machine hundreds > of times per second!
Yes but it uses (or, rather, used) a CMOS flag to skip POST (not only the RAM test) and to go directly to the entry point in real mode.
IIRC (I may be wrong, that was 15+ years ago) only 286 required KBC reset to return to real mode (did LOADALL matter?), 386s have no such problem.
BTW I understand the idea have nothing to do with actual aircraft, so it would be the admin rather than NTSB looking at the data(?). -- Krzysztof Halasa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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