[syslinux] Shift to a Menu

[Murali Krishnan Ganapathy]

Nazo wrote:
> On 1/5/06, Jun OKAJIMA <okajima at digitalinfra.co.jp> wrote:
>   
>> Can you do like this?
>>
>> -----------
>> When booting....
>> {Shift] Pressed -> Go to a menu system, not boot: prompt.
>> Nothing Pressed -> Just booting a default, without time out.
>> -----------
>>              --- Okajima, Jun. Tokyo, Japan.
>>
>>
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>>     
>
> My first reaction was that this sounded silly, at first thought it
> seems you'd want it the other way around only, but, once I thought
> about it, I realized that actually, this is a good idea.  This way,
> you would get a normal default bootup, possibly without even seeing
> anything if you didn't do anything, but, if you wanted to boot
> differently than usual, you'd hold the shift key to get the menu.  I'd
> like to second this idea because it could be kind of nice to see.
>
>   

This should be fairly easy to implement through COMBOOT. It would work 
as follows: SYSLINUX always boots into "shift.c32 menu.c32". shift.c32 
checks if the shift key is pressed (you need to know that a certain BYTE 
in the BIOS DATA area holds this information, Ralph brown's interrupt 
list will have the details) if the shift key is pressed it asks syslinux 
to execute its first argument (in this case menu.c32) else it quits. If 
you want to be wicked you can assign meanings to other combinations. For 
this to really work, the Shift key must be depressed while shift.c32 is 
being executed (so in your documentation say a 5 second shift key), or 
you can check if CAPS-LOCK is on.

- Murali