On Wed, 2010-03-31 at 16:00 -0400, Joshua Oreman wrote: > On Wed, Mar 31, 2010 at 2:49 PM, Itay Gazit <[email protected]> wrote: > > Hi Joshua, all, > > > > Continue to our discussion we had a while ago, I continued my testing on > > entering CLI during POST. > > > > At this experiment I changed the main() to a blank function. > > > > I tested 19 different models machines. The results were that 5 of the 19 > > hanged when exiting from CLI! Including machines from HP, IBM and > > SuperMicro. > > > > My conclusion is that regardless the memory consumption, there is a major > > problem in gPXE when exiting from gPXE during POST. > > > > As I mentioned before, having a reliable CLI during POST is important. > > > > I am willing to continue debug this issue, if you have any idea on how to > > solve it then please let me know. > > I appreciate the testing you've done. > > This is a problem with the BIOS on these machines. On many BIOSes, it > is simply not possible to enter protected mode during POST; attempting > to do so will cause booting to ultimately fail. There are two > solutions: > - have gPXE provide only limited POST-time functionality with real-mode code; > - don't try to use the CLI during POST > > The first is extremely difficult. The second is extremely easy. > > I don't understand - why is it so necessary that you enter the CLI > during POST, as opposed to doing it when gPXE is invoked as a boot > device? 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 ?
Cheers, Jon _______________________________________________ gPXE mailing list [email protected] http://etherboot.org/mailman/listinfo/gpxe
