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Ultra-Quiet Linux Boxes?
Percival asks: "For both noise and power-consumption reasons, I would like to build a silent linux box (i.e: no hard drive, no CPU fan, no PS fan). In my case, I need the box to IP masquerade as well as serve small print jobs through samba, but I can see many uses for a silent linux box. I would like to learn how to build a linux bootdisk that would load everything necessary into a ramdisk. The bootdisk HOWTO is very helpful, but it does not really address building a permanent linux system on a floppy, being aimed at rescue and tool disk creation. (The particulars: 2.2v Pentium MMX CPU with large heat sink, small, low-power PS, floppy disk, motherboard, two NICs, HP LaserIIp). Would I be better-off going with a diskless system (I would rather not have to rely on another linux box to boot)? Is this a pipe dream? "
If you do this then it should not be a problem espescially if you only use an old laptop drive that will be both low power and noise. see my website for a do-it-yourself power supply this one does 100W with no fan off a 12v battery my orientation is for a car player but you can probably get away with an LCD like I use as well. cya, Andrew...
This is my sig, exciting huh!
I think Rebel.com has done an excellent job with the Netwinder. It's a small computer using a SA1100 StrongARM processor. It's the same processor used in the Empeg car audio player and can do what you want and much more. It not only runs Linux, but it was designed specifically for Linux. I had a chance to talk with them at Linux World and I can tell you they're a small shop full of good people.
You may also look at the LART project being done in TuDelft, Netherlands. I don't think they're selling anything (yet?) but it's nice to see Linux on a small processor capable of some real power. I don't have a link handy, oops.
Or, you could use a uCsimm. It's a port of Linux to the Dragonball microcontroller with integrated Ethernet. It all fits on a 30 pin simm complete with Flash. I consider that to be really cool. There are many more choices out there than plain ol' Linux on x86. Don't limit yourself.
They make very quiet CPU fans as well.
A while ago, I saw some solid state disks packaged just like the regular spinning kind, but built with NVRAM or something like that. Very fast. Very expensive. Very quiet. Now that I think about it, probably very hot as well....
There was a company called Ergo that used to make a system called 'the brick'. It was very small (for those days) and had no fan. The case was one big heatsink and they used a clever device to transfer the heat to the case. It looked like an anti static bag (size of one wall of the enclosure, about 3 mm thick) filled with some sort of heat conducting liquid.
You can replace many 'fan required' situations with an oversized heatsink that has outside the case exposure, as long as it has good contact with the hot component. (don't forget the heat sink compound).
Hmmmm maybe that would be a good oddball case direction, something that looks a bit like a porcupine, lots of external heatsink on the case itself....
You have defined what you want (low noise, low power, no hard drive, no cpu fan, no power supply fan), but your reasoning behind what would make the machine silent is a little flawed. Let me elaborate:
Removing all fans from such a machine - indeed, all moving parts - would make it silent, and use less power. However, in the quest of doing so, you will run into issues which begin to raise the cost of the system - such as what to use to boot the system. You indicate that booting with a floppy would be OK if you could get everything you needed on a floppy - so boot noise doesn't seem to be an issue. But running noise - that is, noise generated in normal operation of the machine - is an issue. Solid state disk devices would be the only option (unless you do get a full system on a floppy - which I can't say would be impossible) - and a very costly option.
Running noise seems to be the issue here - the solution is to choose components that make as little noise as possible (until it is inaudible to a human), and will use as little power as possible. To this end, I offer this list:
For the CPU - use an AMD 5X86 OC'd (or not) to 160 Mhz - these can be bought off of eBay or surplus very easy. Use a good 486 heat sink with fan, and compound to cool it. Most fans on 486 heat sinks are inaudible, especially in the case.
Use a 2.5 inch laptop IDE hard drive to boot from. 100 Mb hard drives can be had off of eBay for 5-10 dollars, sometimes less. Wrap the hard drive in some egg-crate - with it inside the case, you won't hear a thing, and the drive won't heat up enough to worry about cooling it.
For the power supply, we need to get creative - go to www.alltronics.com and order their Mini Switcher power supply (stock #98E011). You might want to wire up another Molex connector for the motherboard, as it comes with only a single connector (the one with 12V, -12V, 5V and ground. It doesn't output -5V. In fact, I don't think it is needed, as a machine I have runs fine without the -5V output. Anybody know what the -5V is used for in a PC?). It has 2 standard drive connectors, and one mini connector (for the floppy). I believe it outputs 60 watts without a fan, but add a fan (23 CFM), and output goes up to 80 watts. However, a 23 CFM fan might make too much noise to be comfortable for you - you might want to try smaller fan(s) - maybe 486 coolers, to get a little airflow over the thing (don't just box it up, give it some breathing room).
Think about the area and the noise level the box will be used in. Silence is not being heard because of surrounding noise (it is easy to be "silent" outdoors - just don't make more noise than what is the ambient level outside) - and most rooms have a lot of ambient noise. You may want to get somebody to measure the avaerage dB level of noise in the room - just don't make the box emit more than this level, and the box will be silent.
While what I described isn't "silent" by your definition - it is silent by normal definition - that is, it make so little noise you would be hard pressed to hear it. The loudest thing in this box is going to be the hard drive - and it will be damn quiet. I have built a box similar to this, for an in-vehicle computer system - I use all of the parts mentioned (well, my hard drive is larger - it is a 350 Mb), including the power supply. The hard drive is wrapped in egg crate, and doesn't get hot at all. Neither does the cpu (which is OC'd for playing MP3's). In total, I have spent maybe $50.00 on this system. It doesn't make any noise in a quiet room, and it is definitely inaudible in my vehicle.
What you ask is possible, and easy to do, if you are willing bend your rules a little. Hope this helps...
Reason is the Path to God - Anon
Wouldn't PicoBSD fit in here pretty well? PicoBSD can run a pretty feature-filled system from a floppy.
http://www.freebsd.org/~picobsd/
Also, I've heard PanaFlow fans are really quiet and nice. Check em out in section M of the catalogue at http://www.digikey.com
It's 10 PM. Do you know if you're un-American?
I'm not too big of a fan of mac's myself, but the new iMacs no longer have fans in them and supposedly run very quietly.
First off, you will be better off with a non-x86 processor. Whether they suck in other ways or not, they absolutely suck juice. That said, there's a lot you can do.
Step one: forget the floppy and use a cheap CD-rom drive. They're made to shut down nicely and that way you won't be counting bytes.
Step two: get rid of the heat generation. Use an old-but-not-ancient CPU on a motherboard somwhat newer than it is, with a selection for supply voltages lower than the rated voltage for the CPU. Processor power is proportional to the square of supply voltage and proportional to the frequency, so a reduction from 2.3 to 2.1 volts and from 233 MHz to 200 will result in a 30% power savings. The lower voltage won't support full speed, but will support a derated speed. You'll need to experiment with power, temperature, and clock multipliers. This is like overclocking in reverse; take the speed down (let's say from 233 to 166) and find out where the processor fails at 70C ambient. Put the voltage up a notch and drop the speed to 133 or less. That kind of thing.
Finally, you'll want to slow down the fan. Notice I didn't say 'stop'. Fan noise is amazingly nonlinear. Drop the speed by half and you won't be able to hear it. You can drop the speed by using a lower power supply voltage than design; most fans seem to run on the +12v supply. Try the 5v supply and see if it starts reliably. Alternately, see if you can get a 24 v fan and run it at 12 v. Either way, the speed will be about half of normal, which translates into better than a 10 dB noise reduction. Put the fan behind a baffle and if it's not silent it'll be very close.
I'd be very nervous about shutting the fan down entirely unless the PS is made to work that way (Apple was seriously anti-fan for years) because even in idle there are parts in the power supply itself that dissipate quite a bit of power and depend on air to get rid of the heat. Maybe not a LOT of heat, but when you divide by zero airflow the result ain't pretty.
Lacking <sarcasm> tags,