Some laptops, Asus boards, etc play CD's w/out booting. Special chip, chipset feature or just powering the drive & spkr?

[CZroe]

I read up on Asus' implementation and it looks like they just use the analog out from a CD-ROM and power up the basics (Keyboard controller, analog sound hardware). My laptop didn't do anything strange to make me think it worked any differently, but I thought I saw a Toshiba laptop that could play MP3 CDs when powered off... Wouldn't this require some special decoder chip that interffaces through IDE without using the system's IDE (Which would require using the CPU) implementation? Could it be a feature of the chipset (I read about the Asus implementation in Anand's Via KT800 review)?

Basically, I'm really hoping that a laptop will someday exist that can play MP3 CDs / DVDs without booting for battery life and durability reasons (Who wants the hard drive spinning on a bumpy ride when all you want is the tunes?) and I was never able to confirm that that Toshiba could (I may have just assumed because the CD button said "CD/MP3" when it probably doubled as the media player button in Windows).

 

[magomago]

prolla just x86 coding

my friend's 950mhz athlon4 laptop will do the same thing for cd- it can pka w/o being turned on and i'll ask if he can do it with mp3s

 

[Ichinisan]

I doubt it's simply X86 coding. It would be pretty non-standard for a button to set some flag that the booting BIOS checks before deciding jumping into either the OS Bootloader or the CD-Player code. Besides, the fans never come on so I doubt the CPU is involved at all so nothing X86 boots. If it did work that way it would allow substantial flexibility. So much so that I doubt such a feature would have ever lacked MP3 decoding!