[jan-jaap]

Picked up a new addition to my collection last weekend: a Professional IRIS 4D/50

I met the original user, who used it between 1998 and 1991. Then it went home with him, but not before the entire machine was put through a degausser.

He stored it in his basement, where it sat untouched since 1991. Last week he fired it up, and apparently it came to life. Of course the hard disk is (still) completely erased. He put it on eBay and now it's mine



The system is basically immaculate. I just need to remove 30+ years of dust and grime. Of course I will not just start using and pray nothing blows up. I'm going to have to do a deep inspection and testing, starting from the power supply

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Took off the skin panels to give them a gentle wash. The power supply is in the bottom of the drive bay stack. It's a 1000W MightyMite unit made by L&H Research.

The system disk is a 145MB Toshiba. I hope it can be brought back to life after being degaussed? I may need to low level format it to rebuild the bad sector map

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There's only four boards inside the 12-slot card cage:

• An IP4 @ 8MHz. It looks like I've got 8MB RAM. The IP4 was SGI's successor to the MIPS R2300 MBC (multi board computer) which occupied up to four slots
  
• Clover1 graphics: GF3, DE3 and TB2. The (optional) ZB2 Z-buffer board is not present
  

The DE3 is only ~ 3/4 populated, unlike what Gerhard Lenerz's site shows. I may be missing alpha planes. Perhaps this is 'B' graphics -- 'G' without Z and alpha? The memory may look like 30-pin SIMMs, but the RAM chips are dual ported, Toshiba MB81461-12

The PROM is an older version than what's in my 4D/70 GT. It's

Code:

Version 4D1-2.1 PROM IP4 OPT Tue Nov 10 04:00:37 PST 1987 SGI

It put a copy of the PROM here: https://vdheijden-messerli.net/sgistuff/...onal_IRIS/