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SGI Power Series

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SGI Power Series
SGI Crimson VGX at VCF Midwest 2017 (Patrick Finnegan)
An SGI Crimson, which uses the Power Series single-tower chassis and backplane in red skins. Power Series machines have dark skins (Patrick Finnegan, CC BY 2.0)
Specifications
ManufacturerSilicon Graphics, Inc. (SGI)
TypeMultiprocessor deskside workstation and server; rack-mounted systems
ReleasedOctober 1988[1]
Discontinued1992[2]
CPU1 to 8 MIPS R2000 (16.7 MHz) or R3000 (25, 33 or 40 MHz) processors, each with its floating-point chip, on IP5, IP7, IP9 or IP15 boards[1][3]
MemoryECC memory on the MC2 board, proprietary 80-pin SIMMs; 256 MB maximum[4][1]
StorageSCSI disks and tape; ESDI, SMD and IPI-2 disks on VME controllers[4][5]
Display—
Sound—
GraphicsGTX or GTXB, VGX or VGXT, RealityEngine, or none (server)[1][2]
ExpansionVME slots: four in the deskside chassis, more in the racks[1]
Power115 V nominal (87–132 V), 47–63 Hz, 20 A outlet; 220 V models; 1840 VA, 1310 W (deskside chassis, 1990)[4]
DimensionsTwin tower 65 × 65 × 68 cm; single tower 54 × 66 × 74 cm (W × H × D)[4][1]
WeightTwin tower 84 kg (185 lb); single tower 82 kg (180 lb)[4][1]
OS / FirmwareIRIX 3.x (4D1-3.x) to IRIX 5.3[1][2]
PredecessorProfessional IRIS[1][2]

The SGI Power Series (written POWER Series by SGI) is Silicon Graphics' first range of multiprocessor computers, introduced in October 1988 as part of the IRIS 4D family. The machines use one to eight MIPS R2000 or R3000 processors sharing memory over SGI's POWERpath bus, and were sold as deskside towers and as refrigerator-sized racks, either with GTX, VGX or RealityEngine graphics or as servers.[1][3][2] Gerhard Lenerz of sgistuff.net describes the later SGI Crimson as the last of the 4D Power Series: a Power Series machine with an R4000 processor and memory board, in the same deskside chassis.[6]

SGI's own documents for the range that survive online are marketing and technical overviews. Searches of the Jurassic.nl TechPubs archive, bitsavers and the Internet Archive in October 2026 found no Power Series owner's guide or service manual, so the repair notes in the Power Series guides rely on owners' records, chiefly A. J. Corda's This Old SGI FAQ of 1996–1997, sgistuff.net and jan-jaap's restoration logs on the IRIX Network forums.[7][1][8] See also SGI IRIS 4D.

Models

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The second digit of the model number is the processor count, so a 4D/340 has four 33 MHz processors and a 4D/280 eight 25 MHz ones. A suffix gives the graphics, such as GTX or VGX, or S for a server.[1][3]

Power Series models
Model CPU board Processor Processors Chassis
4D/120 IP5 R2000, 16.7 MHz 2 Deskside
4D/210 IP9 R3000, 25 MHz 1 Deskside
4D/220, 240, 280 IP7 R3000, 25 MHz 2, 4 or 8 Deskside or rack
4D/310, 320, 340, 380 IP7 R3000, 33 MHz 1, 2, 4 or 8 Deskside or rack
4D/420, 440, 480 IP15 R3000, 40 MHz 2, 4 or 8 Deskside or rack

[1][2][9]

SGI's 1989 technical report groups the range as POWER Station servers, POWER IRIS graphics systems and the expandable POWER Center racks; the 1990 brochure markets the VGX machines as PowerVision.[3][4] sgistuff.net dates VGX graphics to 1990 and the 40 MHz 4D/4x0 models to the first half of 1991; jan-jaap says VGX and the 33 MHz IP7 boards arrived with IRIX 3.3 in June 1990.[10] Rebadged machines were sold by Control Data and by Siemens Nixdorf as the RW360.[1]

Hardware

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SGI POWER Series system diagram (Technical Report 1989 Figure 1)
SGI's block diagram of the POWERpath architecture: CPU and FPU pairs with their caches, the Sync Bus and MPlink bus, memory with ECC, graphics and I/O (SGI, POWER Series Technical Report 1989, Figure 1)

Architecture

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Each processor has its own processor bus, 64 KB instruction and 64 KB data first-level caches, and a 256 KB second-level data cache that watches the shared MPlink bus to keep the caches consistent. The 4D/120 has 64 KB second-level caches and the 4D/210 none. A separate Sync Bus gives the processors 65,000 hardware test-and-set variables for fine-grained locking. Memory is protected by error-correcting code, and the I/O system has separate VME, SCSI and Ethernet buses, with VME handled by SGI's DMAP chip.[11][12]

Chassis

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  • Twin Tower: the early two-board systems (4D/120, 4D/210, 4D/220 and 4D/240) came in a 15-slot twin tower, with the card cage and rear connectors in the larger half and the drives in the smaller. The colour of the top hats showed the graphics: red for GTX, blue for VGX and beige for servers.[1]
  • Single Tower ("Diehard"): one enclosure with the card cage behind a door on the left and the drives and control panel on the right, used for systems with up to two CPU boards except the 4D/120. It has a 14-slot backplane.[1]
  • Rack ("Predator"): a dark rack with a 19-slot card cage at the top and drive shelves below, built in POWERCENTER (server), PowerSeries (graphics) and SKYWRITER versions with different backplanes. The POWERCENTER and PowerSeries racks take up to four CPU boards; the SKYWRITER backplane, which holds two graphics sets, takes two.[1][13] jan-jaap's 4D/380 rack stands about 1.6 to 1.7 m tall; its blowers draw air through a grille under the card cage and exhaust it through the top.[5]

Boards

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  • CPU: the IP5 carries two R2000s; the IP9 one R3000 and its own memory sockets; the IP7 is a carrier for up to two plug-in processor modules, each with an R3000, R3010 floating-point chip and cache; the IP15 carries two 40 MHz R3000s. Every CPU board has status LEDs and a card-edge reset switch, and an IP7 carries a set of boot PROMs for each CPU.[1][13][5]
  • Memory: apart from the IP9, which has its own SIMM sockets, the CPU boards carry no memory. Memory goes on the MC2 board, which takes proprietary 80-pin SIMMs of 2 MB or 8 MB, and a system may not have more than 256 MB.[1][14]
  • I/O: the IO2, IO3 and IO3B boards (slot 5 in the deskside chassis) carry the SCSI channel or channels, Ethernet, the VME interface, the PROM monitor and the NVRAM. The IO2 and IO3 use Western Digital 33C93 and 33C93A SCSI chips; the IO3B has two SCSI channels and also serves the Crimson.[1][15]
  • Graphics: GTX (GM2, GE4 and RM1 boards with an RV1.5 or RV2), VGX (GM3, GE6, RM2 and DG1), VGXT (adds VS1 and RM3) and RealityEngine (GE8, DG2 and one, two or four RM4). The slot positions differ between the single and twin towers.[16][17]

Power and cooling

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SGI's 1990 brochure gives a nominal 115 V supply (87 to 132 V) at 47 to 63 Hz from a NEMA 5-20 (20 A) outlet, a chassis load of 1840 VA or 1310 W, and 220 V models for other markets.[4] This Old SGI notes a built-in 16 A circuit breaker and says supplies from LH Research, Cherokee, ACDC and Power-One were used, mostly rated above 1000 W.[18][19] jan-jaap gives 250 A at 5 V for the Power-One supply in his 4D/380 rack; an earlier post of his gives 200 A.[8][5] The system switches itself off if its thermal sensor, at the top of the main tower, reaches 140 °F (60 °C), and a reset switch behind a small hole on the front clears the cut-out once it has cooled.[20]

Software

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The range was introduced when 4D1-3.x was the current release. sgistuff.net says the 4D1-4.x releases support all the basic Power Series models, RealityEngine graphics from 4D1-4.0.5, and that IRIX 5.3 was the last release for the range.[1][2] jan-jaap notes that the last PROM version, built from the IRIX 4.x code, is the one that can boot from CD-ROM.[5]

Known faults

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  • Power supply failure, from leaking electrolytic capacitors and failed components in the bias supply. jan-jaap found leaking capacitors in the supplies of his 4D/380, 4D/440 and Crimson and rebuilt all three. See SGI Power Series Capacitor Replacement Guide.[8][10]
  • Tantalum capacitor failure. On the first power-up of jan-jaap's 4D/380 after several years, with no boards fitted, a tantalum capacitor near the keyboard port on the I/O bulkhead burst into flames.[8]
  • Boards that are very hard to insert and remove because of tarnished backplane connectors; see SGI Power Series General Maintenance.[8]
  • Faulty CPUs and mismatched PROM versions in systems used as spares donors.[5]
  • An exhausted clock and NVRAM battery. This Old SGI says the IO2 and IO3 boards use the same type of SmartWatch module as the Professional IRIS.[21][8]

See SGI Power Series Troubleshooting Guide.

Documentation

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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 Gerhard Lenerz, "PowerSeries", sgistuff.net, sgistuff.net/hardware/systems/powerseries.html (last modified 30 June 2025, retrieved 22 October 2026). Models, history, processors, memory, I/O boards, chassis, backplanes, status LEDs, mode switches, rebadged systems, IRIX support.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 "Power Series", TechPubs Wiki, tech-pubs.net (retrieved 21 October 2026). Release and discontinuation years, models, buses, graphics, IRIX support.
  3. ↑ 3.0 3.1 3.2 3.3 Silicon Graphics, POWER Series Technical Report, 1989, section 1, PDF page 2 (File:SGI POWER Series Technical Report (1989).pdf). POWER Station, POWER IRIS and POWER Center categories; CPU configurations; ECC memory and disk capacity.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Silicon Graphics, PowerSeries/PowerVision brochure, January 1990, technical specifications, archive.org/details/sgi-power-series-1990. Processors, memory to 256 MB ECC in 8 MB steps, disk options, power requirements, chassis size and weight, environment.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 jan-jaap, "Introducing: my PowerSeries 4D/380 VGX", IRIX Network forums, 5 September 2019, forums.irixnet.org. Rack layout and cooling, boards, PROM versions, IPI-2 disk.
  6. ↑ Gerhard Lenerz, "Crimson", sgistuff.net, sgistuff.net/hardware/systems/crimson.html (retrieved 22 October 2026). The Crimson as the last 4D Power Series; same chassis and backplane.
  7. ↑ A. J. Corda, This Old SGI, version 2.0, July 1997, mirrored at sgistuff.net/mirrors/4dfaq. Power Series section added in version 2.0.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 jan-jaap, "DALI, my PowerSeries 4D/380 VGX", IRIX Network forums, 27 June 2025, forums.irixnet.org. Supply rebuilds, backplane connectors, tantalum capacitor failure, minimal boot.
  9. ↑ Corda, This Old SGI, "Power Series: Configuration and Performance".
  10. ↑ 10.0 10.1 jan-jaap and others, "Rebuilding a PowerOne PSU for a 4D PowerSeries/Crimson", IRIX Network forums, April to May 2022, forums.irixnet.org.
  11. ↑ SGI, POWER Series Technical Report, sections 2.2 to 2.2.2 and Figure 1, PDF pages 3–4. Processor bus, first- and second-level caches, Sync Bus, MPlink bus.
  12. ↑ SGI, POWER Series Technical Report, section 2.1 and the I/O buses section, PDF pages 3 and 5. ECC memory; VME (DMAP), SCSI and Ethernet buses.
  13. ↑ 13.0 13.1 Corda, This Old SGI, "CPU card notes". Card types, reset switch, installation rules, up to two CPU cards in a tower and four in a rack.
  14. ↑ Corda, This Old SGI, "Memory Expansion card notes". 256 MB limit; MC2 SIMM sizes.
  15. ↑ Corda, This Old SGI, "IO card notes". SCSI, Ethernet, NVRAM, PROM monitor and audio on the IO boards.
  16. ↑ Corda, This Old SGI, "Graphics Configurations". Board sets for GTX, VGX, VGXT and RealityEngine.
  17. ↑ Corda, This Old SGI, "Graphics Cardset Slot Assignments".
  18. ↑ Corda, This Old SGI, "Power Requirements". 20 A service; built-in 16 A breaker.
  19. ↑ Corda, This Old SGI, "Power Supply problems" (Power Series section). Supply makers and ratings.
  20. ↑ Corda, This Old SGI, "Thermal Sensor and Reset Switch".
  21. ↑ Corda, This Old SGI, "Real time clock & non-volatile memory problems" (Power Series section).


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