[rescue] Divide and conquer

Andrew Weiss ajwdsp at cloud9.net
Thu Jul 24 11:55:15 CDT 2003

On Thursday, July 24, 2003, at 12:39 PM, Peter Corlett wrote:

> Andrew Weiss <ajwdsp at cloud9.net> wrote:
> [...]
>> All PC's boot without a monitor... it's old Macs that don't boot 
>> without a
>> display on the sense pins... something that can be fooled with a Mac 
>> to
>> VGA adapter.
> Ah, I've got a Mac LCII that apparently boots, but nothing comes up on 
> the
> display. I've been told that it's because the battery inside is flat 
> (in
> fact, it's missing :) - would this be the cause, or is there some 
> deeper
> problem?

YES... many old macs WILL NOT boot if the PRAM battery is dead or 
missing.  It's like the NVRAM being missing or dead on a Sparcstation.  
The Powermacs after the x5xx series contain OpenFirmware of course 
which is very similar to Openboot... both are real firmware that have 
Forth interpreters... (Openboot?)

>> All PC's I know of won't boot without a video card. (I've heard there 
>> are
>> rare exceptions, but most machines will just BEEP really loudly 
>> without a
>> VGA adapter)
> Are you sure that's a failure, or just a warning?
Failure.  The machine stays like that... BEEEP BEEEP BEEEP BEEP... 
forever.... no other discernable activity except continuous 3 second 
long beeps.

> I agree that they beep loudly when no video card is detected, but they 
> will
> often just contine with POST and boot anyway.
>> Many PC's don't boot without a keyboard attached.
> Booting without a keyboard is such a common requirement, I've yet to 
> see a
> machine that wouldn't do so when you select the blatantly obvious 
> option in
> the BIOS.

Case in point... the HP Vectra VA 6/200 I have at work has no such BIOS 
option.  I have also seen many others that have no BIOS option to keep 
booting on POST errors...or ignore keyboards.  I have also seen many 
that would allow this.


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