Silicon Graphics Indigo R4400 w/Elan Graphics
The Indigo is one of the most capable graphics workstations of its era, and was essentially peerless in the realm of hardware-accelerated three-dimensional graphics rendering. It was produced between 1991 and 1995. This R4400 Indigo uses a 150Mhz MIPS R4400(IP20) CPU processor and can support up to 384M of RAM. It also contains Elan Graphics with 4 Geometry Engines and 24-bit color.
Acquisition
I acquired the R4400 while working on the R3000 Indigo with the failed power supply. The R4400 is superior to the R3000 as it is faster, runs a more recent version of Irix, and has much better graphics. I met the previous owner on a forum talking about the SGI machines. He was moving and needed to get rid of several computers (in fact, an entire garage full). I thought about it for a day, but that R4400 was too good to pass up. It arrived a week later.
A lot of indigos out there have been pretty beat up. In contrast this machine was in very good shape and was mostly restored by the last owner.
Configuration
Model: Indigo R4K Elan, XS, XS24
CPU: 1 150Mhz MIPS R4400(IP20) Processor, MIPS R4000 FPU
Main Memory: 384MB of Memory
Data Cache: 16KB
Instruction Cache: 16KB
Secondary Instruction-Data Cache: 1MB
Operating System: Irix Release 6.5
Audio: Iris Audio Processor revision 10
Graphics: GR2-Elan
Graphics Info: Graphics Board 0 is “GR2” graphics. Managed(“:0.0”) 1280x1024. 4 GE’s, 1R.E. 24 bitplanes, 4 auxplanes, 4 cidplanes, Z-buffer
GR2 revision 2, VB1.1, HQ2 rev A, GE7 rev B, RE3 rev D, MC rev B.
Monitor Unknown, Assumed 19: monitor
Network: Interated Ethernet: ec0, version 1
Parallel Ports: On-board bi-directional parallel port.
SCSI Controller: WD33C93B
Units In Use: 1, 6
ZuluSCSI Configuration
I have to say the R4400 was in perfect condition.
The previous owner had installed a SCSI2SD V6 drive in the top bay and had even 3D printed a new inner drive bezel to allow the LED to be seen through it when the Indigo drive bay door is open. He did a top-notch job. The machine was running Irix 5.x, and I used it that way for a bit, but I ended up installing Irix 6.5 onto the box, as that is what my Indy runs. Irix 6.5 is just a bit more mature and more standard version of Irix.
I exclusively use ZuluSCSI RP2040 cards in my workstations. Initially, about half of my systems were equipped with SCSI2SD V6 cards, which worked great. However, during the pandemic, parts for those cards became nearly impossible to obtain. Toward the end of the pandemic, ZuluSCSI cards were introduced to the market, offering significant improvements.
One of the main enhancements is the use of standard files for disk images. This was a game changer, making it much easier to back up and share images.
Cleanup
This computer did not need any significant work, which was nice. I did take it all apart and ran the boards through the dishwasher on the fast cycle, then dried them in a warm oven (100 deg for 6 hours). I took the chassis with the backplane in it to my workshop and blew it out with compressed air, then wiped everything down with isopropyl alcohol.
The iconic Indigo blue case was in pretty good shape. It had a few scuffs but was serviceable. I had purchased a new old stock case a month or so earlier, and it was marginally better, so when I reassembled the Indigo, I used the new case. The hinges on the front door of indigos are almost always broken in any Indigo I have seen for sale or otherwise. The case that I got with the R4000 had new plastic hinges fabricated (and the work was impeccable), but my new case had original hinges so went with that. I think Indigos with Elan Graphics that came from SGI in that configuration had an Elan Graphics logo on the door. None of my cases had that, but I’m not sure that’s uncommon if the box was upgraded to Elan graphics along the way.
Irix 6.5 Install
I really wanted Irix 6.5 on the box, and it was running Irix 5.x. When I restored my SGI Indy, I ended up using my Sun CDROM drive, and it worked perfectly. All the workstation CDROM drives back in the day used 512-byte sectors. Most newer CDROM drives use much larger sector sizes and, as a result, don’t work well with period workstations. Some devices, specifically used in early SCSI macs often have a sector-size jumper that you can set and they too will work with Workstations of this era.
When I acquired my SGI Indy, it came with a complete set of 6.5 OS CDs. This was extremely fortunate because I'm not sure how I would have done the install with just CD images on the SCSI2CD. A full Irix 6.5 install is like 10 CDs, and you shuffle them in and out a lot. Fortunately, the install went without a hitch, and in no time (well a day), it was up and running on my network.
Power Supply
This Indigo came with a working power supply. My R3000 did as well but quickly failed after I received it. The R4400 Indigo seems to work fine, except I can see faint noise on the screen. I think it’s probably a failing filter capacitor that hasn’t completely failed yet. I have never been a proactive capacitor replacer in any of my machines. Electrolytics from the 90’s era fail quite often, but earlier and later capacitors tend to be much better. I am considering proactively replacing the capacitors in the R4400 supply, especially knowing how much work it takes to build a new power supply as I did for the R3000.
The Indigos all use substantial current at both +5 and +12 volts. The +5V amp rating is around 35A. That is well beyond the specs of most ATX-style modern computer power supplies.
Retro-Recreation Monitor
The Indigo is such a joy to use. It's fast, and the Desktop UI was light years ahead of where the other workstation vendors were at the time. The R4000 with Elan graphics has a native resolution of 1280x1024 that works perfectly with one of my go-to LCD displays for period workstations. I enjoyed using the Indigo so much that I decided to, again, create another retro-recreation LCD monitor for the R4000 matching the SGI Indigo Purple/Blue perfectly using only two different colors of paint. I had done the same with the Teal SGI Indy, and it turned out perfectly. After a few days of messing around in my workshop, the monitor was ready to go. I acquired another SGI Logo (the same person I bought from for the Indy), and it was done. The machine is an absolute gem.
Final Thoughts
As I mentioned, the R4400 Indigo is probably my favorite in my collection, with the possible exception of Sun IPX. The Indigo is the superior machine for the era, in my opinion, but the IPX was just such a great swiss army knife and my first Workstation class computer, so I will always have a soft spot for the IPX.