SGI: Hardware

I'd like to turn my R5000 O2 into an ultra-silent machine. My idea is to use an SSD, and also, if possible, replace the PSU by something _really_ quiet. The R5K O2 has no fans inside, but I guess the PSU fan is needed for keeping the machine healthy, so I guess I cannot put a fanless PSU here.

Basically, I'd like to have an O2 which is so silent that you cannot tell if it's on or off. Something like a Macbook Air, for example.

Do you have any suggestion for the PSU? I've searched for silent PSUs, but didn't arrive to a conclusion (not to mention I've no idea if I could mount a third-party PSU on the O2, or how)

Regarding the SSD, I've read some threads on this forum, with posters saying successful use of SSD on IRIX via conversion boards. Is there some preferable choice over other?

Last, but not least, for USB mass storage, do you think this NAS device will work on IRIX? : http://www.addonics.com/products/nas40esu.php

There is at least one thread here about fitting a Noctua fan into an O2 power supply. I did that - no idea if that will be quiet enough for you but it does make a big difference. If your background noise is as high as mine you can't hear it at all, literally have to look at the green light to see if the O2 is running.

Did you take some care because of the different air flow from the original fan, like Ian said? (just asking, mine is a 180MHz R5K but I push CRIME graphics quite a lot!!)

Also, people who has installed SSDs on IRIX, can an SSD be the only disk (and of course be bootable) on an O2? Reading some threads, I seem to read you've to tweak drivers or something to make the SSD bootable, so I'm not sure if my wish is feasible...

I'll split up this post in the two categories of noise you mention:

Fan
The O2 dates from ~ 1996. Back then most computers were loud(er), but a lot of progress was made in fan technology. The Noctua could very well move the same amount of air as the original fan with much less noise (I didn't check, though). Anyway, the original fan must be 15 years old by now and the bearings must be dry or worn out so your O2 is now probably louder than it was when it was new.

The O2 fan runs at a fixed, full speed and was designed to provide enough airflow to cool:
* The mainboard
* Maximum conversion losses (heat) in the PSU. So under maximum PSU load.
* The fattest CPU an O2 could possibly hold. An R12K puts out a lot more heat than an R5000, and maybe it was designed for en even hotter running CPU?
* Maximum RAM.
* 1600SW/dual display daughter card.
* Maximum power dissipation (per PCI standard) for one PCI slot. I could check, but IIRC it's at least 25W.
* A healthy margin to avoid overheating even a fully loaded system.
* All of that at an unknown ambient temperature which is probably higher than what you have in a normal house/office.

In other words, if you know you've got a cool running CPU, half populated memory banks and no PCI card, and you don't lock it up in a closet, you can probably get away with (a bit) less than original airflow without roasting the internals. If you can limit power consumption you win twice because (due to relatively low efficiency of the oldskool PSUs) you will also reduce heat generated inside the PSU.

Also, modern day PC's are quiet, but only when cool. The fan speed is dynamic and fan control (and the noise) will kick in if the system runs hot. Isn't there a decent fan with dynamic (temperature dependent) speed, all builtin? You could enjoy the silence without worrying about overheating.

Disk
If you were hoping to netboot the O2 from that NAS dongle: forget it. IIRC, to netboot an IRIX system, you need at least bootp support, TFTP to load the kernel and NFS for the rest. Even if you have a full blown Linux system available, it requires kernel tweaks. This thing serves the disks up using FTP and SMB protocols -- rather useless for an O2.

Diskless operation in general is slow, due to the latency introduced by the network stack and the 10MB/s throughput limit. There's only one thing more hateful than a diskless UNIX system, and that's swapping over the network

As for the SSD:
1. The O2 only boots from Adaptec 2940 chips (or ethernet).
2. SCA SSDs exist but they are very, very expensive.
3. SCA-to-2.5"-SATA adapters exist, and would allow you to install a regular SSD in the original disk sled. If the SCA-SATA adapter does the conversion properly, then it's just another SCSI disk as far as the O2 is concerned and there's no reason it wouldn't boot. While a lot cheaper than SCSI SSD's, the price of these adapters is still such that I'm not going to verify that claim myself

I can confirm that an SSD works as could a few others here on the forum. As for the noise I was hoping for the same thing but as jan-jaap stated, it was designed to provide proper airflow if needed. To be honest, I was still considering the fan swap until his better explanation as to why it may not be best. Short of anything populating the PCI slot, my O2+ is maxed. I am a bit fortunate as I just moved and my new space is naturally nosier than the last and the O2+ is not too noticeable anymore even with having it on my desk.

Maybe try the SCSI-IDE adapter and going the compactflash route...

In a quiet room you can still hear an MBA and even in a noisy room you can hear the MBA when it is encoding media or playing a game. There is no such thing as a 'silent' computer fan unless it is in a different room

The fan in the MBA only operates when needed. Most of the times it's off. And, even when it's at full speed, you hear it but it doesn't generate a "pitch", but just air flowing, similar to a white noise sound, which doesn't hurt. Moreover, whenever I've turned off any SGI in the past, no matter the model, I realized how much noise it was generating: my ears always experienced the typical pitch you get when you exit a pub or disco with loud music. This never happens with the MBA or most Macs: in the worst case you notice a low noise fan turning off, but you don't get that "peace experience" you notice when turning off an SGI.

Anyway, from what I'm reading, I think it might be easier to finish the Indy emulator in MESS and run it on a silent computer, than doing this silent O2 project, which might be not only expensive, but also requiring some tweaking.

As if millions of voices cried out in terror, and were suddenly silenced...

Maybe the newer models...

Yeah, mine cost me eight bucks. I didn't have enough money to eat for two weeks.