[gPXE] Machines hangs when exiting from CLI

[Jonathan Andrews]

On Wed, 2010-03-31 at 17:00 -0400, Joshua Oreman wrote:
> 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.
> 
I was always told the initial call was simply to allow the feature ROM
to participate in POST itself and if unused should just be a RET ? The
order of POST is not fixed - the list of tasks is similar but can you
can say little about the machine other than its has "some RAM" at this
point ? In the AT/286 days that was all that could be said here.

Cheers,
Jon