Ultimate Linux Box 2005
Listing 1. Partition scheme as seen in /etc/fstab.
LABEL=/nstor-OS / ext3 defaults 1 1 LABEL=/cfboot /boot ext3 defaults 1 2 LABEL=/nstor-DATA /u1 ext2 defaults 1 2 none /dev/pts devpts gid=5,mode=620 0 0 none /dev/shm tmpfs defaults 0 0 none /proc proc defaults 0 0 none /sys sysfs defaults 0 0
Because we wanted the system to be self-contained and not depend on another server to boot, we installed a Sandisk 256MB CompactFlash card to boot from. This device looks exactly like another ATA drive to the system, so any PC motherboard will boot from it.
We considered using a USB thumbdrive, but that would have required some initrd drive juggling and GRUB wizardry. There are advantages to being able to pull your boot device out of the system and store it separately, but we didn't anticipate shipping the system through airports with drives loaded with encrypted confidential data.
If you plan to leave your silent Linux system on your network, you'll be a little more flexible in booting, and you can set up PXE booting. But if you want to take your Ultimate Linux Box over to a friend's house to play some music, you'll want to be able to boot independently. The Penguin crew plans to take this system to LinuxWorld Conference and Expo, and when you're wrangling hardware for a tradeshow one fewer thing to set up is good.
If you do build and install a silent Linux box, you'll probably end up doing a mix of both: NFS for user home directories, the company /usr/local/bin/ and other items that need to be in sync but aren't performance-critical. You can save your machine's own filesystems for big working files, like all the audio data you'll get from this system's high-end sound hardware.
Finally, to take even the keyboard clicking out of the silent system, Penguin founder Sam Ockman suggested a TouchStream LP keyboard, which works like a touchpad and requires no moving parts. It's also a pointing device and lets you map gestures to interface actions.
For the first time, we put professional audio hardware into the Ultimate Linux Box. What better place for a silent machine than the recording studio?
The RME Hammerfall HDSP9652 card we chose for this system is capable of up to 52 channels, and we matched it with an external box called the Multiface that brings out 8 1/4" jacks, as well as optical, coax and MIDI.
This card is as close as you can get to a “studio in a box”, because it's built around an internal mixer and allows you to route signals around inside the card with low latencies and low load on the CPU. Other features include the ability to “punch in” and “punch out” like a conventional tape deck.
Best of all, RME has been supporting the Advanced Linux Sound Architecture (ALSA) Project since 2000, so Linux users aren't second-class citizens. RME's site says, “ALSA support for the Hammerfall breaks the annoying chicken/egg principle—no professional hardware/driver, no professional software.”
Peter Todd covered the necessary tools for working with the Hammerfall HDSP cards in our October 2003 issue.
For video, we used a relatively low-end card (see the on-line Resources). We'd really like to start putting interesting and innovative video on Ultimate Linux Boxes, but there are still some issues with the drivers (see sidebar).
So how do we keep this thing cool? First of all, it's important not to start tweaking with hardware combinations unless you know how to measure the effects that your changes have on the system's temperature. Don't change anything unless you know how to measure the effect of the change.
The good news is that the processor and motherboard vendors thoughtfully give us temperature sensors right on the key parts. And we can keep track of them using an all-important tool, lm_sensors.
We didn't have to measure drive temperature because we moved the drives to a separate enclosure, but smartmontools (see Resources) gives you an easy way to do that.
We ordered up some parts from Zalman, which offers a beautiful set of water-cooling hardware. The most visible part is the Reserator 1, a combined water reservoir and radiator that stands half a meter tall and holds 2.5 liters of water. Besides the Reserator, we also ordered one CPU waterblock per processor and matching tubing.
Thermal estimates showed that we wouldn't need a full Reserator per processor, so we used one Reserator per two processors and one for the power supply.
The Reserator comes with a 5W pump, which would break our beautiful silence, so it was time to convert it to operate purely by convection. In its stock configuration, the Reserator's inlet and outlet are close to each other, so we installed a tube inside each Reserator, running from the hot inlet to near the top.
Did it work? The processor temperature climbed to about 50° C, then the tubes leading up from the processors to the Reserators warmed enough to start the convection. Temperature fell to 47° or 48° C in normal use, and running full-out, the system holds out below 50° C.
Cooling the power supply was a little harder. Zalman's beefiest fanless power supply is only 400W, and a big four-way board needs more. We decided to use the PC Power and Cooling Turbo-Cool 510 ATX.
We decided not to design and build a power supply for the project, since it's important to apply power to components in the right order, and we know PC Power and Cooling solved that problem for us. The cooling problem remained.
Enter the magic of metalworking. Phil brought the problem to a machine shop called Global Precision, and we had them do three pieces of work. They machined down the original fins of the power supply's heat sinks to create flat areas for attaching waterblocks. They made the waterblocks themselves—using blue anodized aluminum to match the Zalman parts. And they made two custom Y-connectors to split the water flow between the two heat sinks.
We removed the fan control board from the power supply. We didn't need it any more.
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