sgi

Resurrecting an SGI O2

Years ago, I was getting into Linux on esoteric architectures, which started with a Gateway Microserver which runs the MIPS architecture… to better understand this platform I also obtained a few SiliconGraphics workstations, including this O2.

Originally a R5000SC at 180MHz and 128MB RAM, I managed to get hold of an RM5200 300MHz CPU module for it, and with the help of people on the #mipslinux channel on the old irc.freenode.net, managed to obtain a PROM update to get the RM5200 working. Aside from new HDDs (the original died just recently), it’s largely the stock hardware.

I figured it deserved to go to a new home, and a fellow on Gumtree (in WA) happened to be looking for some of these iconic machines, so I figured I might as well clean this machine up as best I can and get it over there while it’s still somewhat functioning. That said, age has not been friendly to this beast.

  • the CD-ROM drive tray gear has popped off the motor spindle, rendering the CD-ROM drive non-functional
  • in trying to fix the CD-ROM issue (I tried disassembling the drive but couldn’t get at the parts needed), the tab that holds the lid of the machine on broke
  • the PSU fan, although free to spin, does not appear to be operational
  • the machine seems to want to shut off after a few minutes of run-time

The latter two are related I think: likely things get too hot and a protection circuit kicks in to turn the machine off. There’s no dust in the machine to cause a lack of air flow, I thus suspect the fan is the issue. This will be my biggest challenge I suspect. It looks to be a fairly standard case fan, so opening up the power supply (not for the feint of heart!) to replace it with a modern one isn’t out of the question.

The CD-ROM drive is a different matter. SGI machines use 512-byte sectors on their CDs, and this requires CD-ROM firmware that supports this. I have a couple of Plextor SCSI drives that do offer this (there is a jumper marked “BLOCK”), but they won’t physically fit in the O2 (they are caddy-loading drives). Somewhere around the house I have a 68-pin SCSI cable, I should be able to link that to the back of the O2 via its external SCSI port, then cobble together a power supply to run the drive externally… but that’ll be a project for another day.

A working monitor was a possible challenge, but a happy accident: it seems some LCD montiors can do sync-on-green, and thus are compatible with the O2. I’m using a little 7″ USB-powered WaveShare LCD which I normally use for provisioning Raspberry Pi PCs. I just power the monitor via a USB power supply and use the separately-provided VGA adaptor cable to plug it into the O2. So I don’t have to ship a bulky 20″ CRT across the country.

The big issue is getting an OS onto the thing. I may have to address the sudden-shutdown issue first before I can get a reasonable chance at an OS install. The big problem being an OS that these things can run. My options today seem to be:

  • Debian Jessie and earlier (Stretch dropped support for mips4 systems, favouring newer mips64r2/mips32r2 systems)
  • Gentoo Linux (which it currently does run)
  • OpenBSD 6.9 and earlier (7.0 discontinues the sgi port)
  • NetBSD 9.2
  • IRIX 6.5

The fellow ideally wants IRIX 6.5 on the thing, which is understandable, that is the native OS for these machines. I never had a full copy of IRIX install media, and have only used IRIX once (it came installed on the Indy). I’ve only ever installed Gentoo on the O2.

Adding to the challenge, I’ll have to network boot the thing because of the duff CD-ROM drive. I had thought I’d just throw NetBSD on the thing since that is “current” and would at least prove the hardware works with a minimum of fuss… but then I stumbled on some other bits and pieces:

  • irixboot is a Vagrant-based virtual machine with tools needed to network-boot a SGI workstation. The instructions used for IP22 hardware (Indy/Indigo² should work here because IP32 hardware like the O2 also have 32-bit PROMs)
  • The Internet Archive provides CD images for IRIX 6.5, including the foundation discs which I’ve never posessed

Thus, there seems to be all the bits needed to get IRIX onto this thing, if I can get the machine to stay running long enough.

Demise of classic hardware

So, this year I had a new-year’s resolution of sorts… when we first started this “work from home” journey due to China’s “gift”, I just temporarily set up on the dinner table, which was of course, meant to be another few months.

Well, nearly 2 years later, we’re still working from home, and work has expanded to the point that a move to the office, on any permanent basis, is pretty much impossible now unless the business moves to a bigger building. With this in mind, I decided I’d clear off the dinner table, and clean up my room sufficiently to set up my workstation in there.

That meant re-arranging some things, but for the most part, I had the space already. So some stuff I wasn’t using got thrown into boxes to be moved into the garage. My CD collection similarly got moved into the garage (I have it on the computer, but need to retain the physical discs as they represent my “personal use license”), and lo and behold, I could set up my workstation.

The new workspace

One of my colleagues spotted the Indy and commented about the old classic SGI logo. Some might notice there’s also an O2 lurking in the shadows. Those who have known me for a while, will remember I did help maintain a Linux distribution for these classic machines, among others, and had a reasonable collection of my own:

My Indy, O2 and Indigo2 R10000
The Octane, booting up

These machines were all eBay purchases, as is the Sun monitor pictured (it came with the Octane). Sadly, fast forward a number of years, and these machines are mostly door stops and paperweights now.

The Octane’s and Indigo2’s demises

The Octane died when I tried to clean it out with a vacuum cleaner, without realising the effect of static electricity generated by the vacuum cleaner itself. I might add mine was a particularly old unit: it had a 175MHz R10000 CPU, and I remember the Linux kernel didn’t recognise the power management circuitry in the PSU without me manually patching it.

The Indigo2 mysteriously stopped working without any clear reason why, I’ve never actually tried to diagnose the issue.

That left the Indy and the O2 as working machines. I haven’t fired them up in a long time until today. I figured, what the hell, do they still run?

Trying the Indy and O2 out

Plug in the Indy, hit the power button… nothing. Dead as a doornail. Okay, put it aside… what about the O2?

I plug it in, shuffle it closer to the monitor so I can connect it. ‘Lo and behold:

The O2 lives!

Of course, the machine was set up to use a serial console as its primary interface, and boot-up was running very slow.

Booting up… very slowly…

It sat there like that for a while, figuring the action was happening on a serial port, I went to go get my null modem cable, only to find a log-in prompt by the time I got back.

Next was remembering what password I was using when I last ran this machine. We had the OpenSSL heartbleed vulnerability happen since then, and at about that time, I revoked all OpenPGP keys and changed all passwords, so it isn’t what I use today. I couldn’t get in as root, but my regular user account worked, and I was able to change the root password via sudo.

Remembering my old log-in credentials, from 22 years ago it seems

The machine soon crashed after that. I tried rebooting, this time I tweaked some PROM settings (and yes, I was rusty remembering how to do it) to be able to see what was going. (I had the null modem cable in hand, but didn’t feel like trying to blindly find the serial port at the back of my desktop.)

Changing PROM settings
The subsequent boot, and crash

Evidently, I had a dud disk. This did not surprise me in the slightest. I also noticed the PSU fan was not spinning, possibly seized after years of non-use.

Okay, there were two disks installed in this machine, both 80-pin SCA SCSI drives. Which one was it? I took a punt and tried the one furtherest away from the I/O ports.

Success, she boots now

I managed to reset the root password, before the machine powered itself off (possibly because of overheating). I suspect the machine will need the dust blown out of it (safely! — not using the method that killed the Octane!), and the HDDs will need replacements. The guilty culprit was this one (which I guessed correctly first go):

a 4GB HDD was a big drive back in 1998!

The computer I’m typing this on has a HDD that stores 1000 of these drives. Today, there are modern alternatives, such as SCSI2SD that could get this machine running fully if needed. The tricky bit would be handling the 80-pin hot-swap interface. There’d be some hardware hacking needed to connect the two, but AU$145 plus an adaptor seems like a safer bet than trying some random used HDD.

So, replacement for the HDDs, a clean-out, and possibly a new fan or two, and that machine will be back to “working” state. Of course the Linux landscape has moved on since then, Debian no longer support the MIPS4 ISA that the RM5200 CPU understands, Gentoo still could work on this though, and maybe OpenBSD still support this too. In short, this machine is enough of a “go-er” that it should not be sent to land-fill… yet.

Turning my attention back to the Indy

So the Indy was my first SGI machine. Bought to better understand the MIPS processor architecture, and perhaps gain enough understanding to try and breathe life into a Cobalt Qube II server appliance (remember those?), it did teach me a lot about Linux and how things vary between platforms.

I figured I might as well pop the cover and see if there’s anything “obviously” wrong. The procedure I was rusty on, but I recalled there was a little catch on the back of the case that needed to be release before the cover slid off. So I lugged the 20″ CRT off the top of the machine, pulled the non-functioning Indy out, and put it on the table to inspect further.

Upon trying to pop the cover (gently!), the top of the case just exploded. Two pieces of the top cover go flying, and the RF shield parts company with the cover’s underside.

The RF shield parted company with the underside of the lid

I was left with a handful of small plastic fragments that were the heat-set posts holding the RF shield to the inside of the lid.

Some of the fragments that once held the RF shield in place

Clearly, the plastic has become brittle over the years. These machines were released in 1993, I think this might be a 1994-model as it has a slightly upgraded R4600 CPU in it.

As to the machine itself, I had a quick sticky-beak, there didn’t seem to be any immediately obvious things, but to be honest, I didn’t do a very thorough check. Maybe there’s some corrosion under the motherboard I didn’t spot, maybe it’s just a blown fuse in the PSU, who knows?

The inside of the Indy

This particular machine had 256MB RAM (a lot for its day), 8-bit Newport XL graphics, the “Indy Presenter” LCD interface (somewhere, we have the 15″ monitor it came with — sadly the connecting cable has some damaged conductors), and the HDD is a 9.1GB HDD I added some time back.

Where to now?

I was hanging on to these machines with the thinking that someone who was interested in experimenting with RISC machines might want them — find them a new home rather than sending them to landfill. I guess that’s still an option for the O2, as it still boots: so long as its remaining HDD doesn’t die it’ll be fine.

For the others, there’s the possibility of combining bits to make a functional frankenmachine from lots of parts. The Indy will need a new PROM battery if someone does manage to breathe life into it.

The Octane had two SCSI interfaces, one of which was dead — a problem that was known-of before I even acquired it. The PROM would bitch and moan about the dead SCSI interface for a good two minutes before giving up and dumping you in the boot menu. Press 1, and it’d hand over to arcload, which would boot a Linux kernel from a disk on the working controller. Linux would see the dead SCSI controller, and proceed to ignore it, booting just fine as if nothing had happened.

The Indigo2 R10000 was always the red-hedded step child: an artefact of the machine’s design. The IP22 design (Indy and Indigo2) was never designed with the intent of being used with a R10000 CPU, and the speculative execution features played havoc with caching on this design. The Octane worked fine because it was designed from the outset to run this CPU. The O2 could be made to work because of a quirk of its hardware design, but the Indigo2 was not so flexible, so kernel-space code had to hack around the problem in software.

I guess I’d still like to see the machines go to a good home, but no idea who that’d be in this day and age. Somewhere, I have a partial disc set of Irix 6.5, and there’s also a 20″ SGI GDM5410 monitor (not the Sun monitor pictured above) that, at last check, did still work.

It’ll be a sad day when these go to the tip.