[CentOS] boot process glitch due to missing 2nd disk

This is not a "Dell-specific BIOS hack". Dear child, ask your folks about
PCs. I think it was only this decade that PCs would actually boot
*without* a keyboard. EVERY PC EVER MADE before would not.

Nah! Every BIOS since I remember (at least from 1990) had a choice on 
the first page, Standard BIOS Setup. "Halt on all errors, Halt on 
keyboard/video errors, Halt on no errors". At least these three were 
always present.

Of course the default is always "Halt on all errors". Unless you modify 
the settings on purpose, that's what happens.