Many thanks to logik for this work of brilliance. Posted with permission, and slightly reformatted here.

A stoner, takes a puff of his joint and says, "Hi, I'm a mac!".
The poorly dressed wannabe bank teller beside him says, "... and I'm a PC."

The door nearby blows in and a heavily armed tactical team storms the room,
throwing both of them to the floor, barrels of MP5k's against their skulls.

Someone yells, "AREA CLEAR!"
The lieutenant comes in after them, smoking a cigar, surveying the area.
"I'm Solaris,
the sergeant over there is BSD (You remember your daddy mac?),
the pretty boy with the M14, he's Linux,
and the guy toting the M60... That there is HPUX.
Now, shut the fuck up, both of you.
We've had about enough of your 'Bill and Ted Get a Computer' bullshit.
Keep it up, and we're gonna do the same thing to you that we did to OS2, got it?"

Following up on my earlier posting on the AD2000BX/AD1989B SPDIF support being broken, I figured out the required fixes, and they are waiting in the sound-2.6 kernel tree for the next merge window

• ALSA: HDA: patch_analog: Implement multiple outputs for AD1988
• ALSA: HDA: patch_analog: Quirk for Asus P5Q Premium/Pro boards.
• ALSA: HDA: hda_proc: Fix printf format specifier
• ALSA: HDA: hda_local: Less magic numbers.
• ALSA: HDA: patch_analog: Fix SPDIF output on AD1989B

Setting up the storage on my new machine, I just ran into something really interesting, what seems to be deliberate usable and useful, but completely undocumented functionality in the MD RAID layer.

It's possible to create RAID devices with the initial array having 'missing' slots, and then add the devices for those missing slots later. RAID1 lets you have one or more, RAID5 only one, RAID6 one or two, RAID10 up to half of the total. That functionality is documented in both the Documentation/md.txt of the kernel, as well as the manpage for mdadm.

What isn't documented is when you later add devices, how to get them to take up the 'missing' slots, rather than remain as spares. Nothing in md(7), mdadm(8), or Documentation/md.txt. Nothing I tried with mdadm could do it either, leaving only the sysfs interface for the RAID device.

Documentation/md.txt does describe the sysfs interface in detail, but seems to have some omissions and outdated material - the code has moved on, but the documentation hasn't caught up yet.

So, below the jump, I present my small HOWTO on creating a RAID10 with missing devices and how to later add them properly.

( MD with missing devices HOWTO )

One of the other Linux folk linked to this, and I thought some others on my list might enjoy it as well.
http://orbis-terrarum.net/~robbat2/edf4.jpg