[gPXE] Machines hangs when exiting from CLI
Joshua Oreman
oremanj at rwcr.net
Wed Mar 31 17:00:14 EDT 2010
On Wed, Mar 31, 2010 at 4:53 PM, Jonathan Andrews <jon at jonshouse.co.uk> wrote:
> Excuse my ignorance .... I don't see HOW you would enter a CLI before
> POST. When I was programming against BIOS 20 years ago the "feature ROM"
> hook was not activated until after POST. Before POST interrupts where
> disabled - IRQ 1 (keyboard) and INT10(video)where simply not available,
> INT10H video hook was only active as the last stage in POST. In short
> pre-POST is zero video, zero keybaord as far as I know ?
No one's doing anything before POST; this is during POST.
Option ROMs have an "init" routine that is executed during POST. Its
main job is to hook other interrupts so the work the ROM actually
wants to provide (e.g. an additional hard disk or a network boot) can
be executed after POST, but it's also possible to do things directly
at that time. Some expansion cards use this to provide a configuration
menu prompt.
-- Josh
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