4.x or 5.x for newbie install on laptop?

[M. Warner Losh]

In message: <20030921192420.GD4779 at pir.net>
            Peter Radcliffe <pir at pir.net> writes:
: The cutouts/keys on the end of the card are different, to make sure
: that you don't manage to put 32bit cards into 16bit only slots (16bit
: only comtrollers/slots are quite hard to find these days in my
: experience, just very old laptops).
: 
: The 16 bit cards have this shape on the sides of the connector;
: 
: |  o o o o...o o o o |
:  |        ...        |
: |  o o o o...o o o o  |
: 
: Whereas the 32 bit cards have this shape;
: 
: |  o o o o...o o o o |
:  |                    |
: |  o o o o...o o o o  |
: 
: So 16bit cards will go into 32bit controllers but 32bit cards will not
: go into 16bit controllers.

Actually, that's not why they are different.  The 32-bit ones are "low
voltage" cards and operate at 3.3V only.  The typical 16-bit card
operates at 5.0V and is a high voltage card.  There are a number of
"Low voltage" 16-bit cards that operate only at 3.3V and they are
keyed like you drew the 32-bit card.

A better distinction is to look for the ground plane on 32-bit cards.
it is copper and has a number of bumps on it.  That's universally the
distinction (although I've seen one or two 16-bit cdrom controllers
that have the cardbus stripe on them that were rumored to  be 32-bit
on external power, but I've never been able to confirm that).

: Then it won't work with 4.x. I don't know if there is support for
: firewire (in particular) cardbus cards in 5.x.

There is for the fwohci chips.  There's none for Sony's earlier,
proprietary firewire controller.

Warner