Please consider a donation to the Higher Intellect project. See or the Donate to Higher Intellect page for more info.

SGI Octane

From Higher Intellect Vintage Wiki
Jump to navigation Jump to search
SGI Octane

The SGI Octane (and the very similar SGI Octane2) are UNIX workstations marketed by SGI. Both are SMP-capable (up to 2 identical processors) workstations, originally based on the MIPS architecture R10000 processor. Newer Octanes are based on MIPS R12000 and R14000. Octane2 has four improvements compared to Octane. Octane2 has revised power supply, system-board and xbow. Octane2 also shipped with VPro graphics and supports all available VPro cards (V6, V8, V10 and V12). Later revision Octanes also included some of the improvements mentioned. The machines shared a codename "Racer" or "Speedracer" inside SGI.

The Octane was the direct successor to the SGI Indigo2, and itself was succeeded by the SGI Tezro, and its immediate sibling is the SGI O2. SGI withdrew the Octane2 from the price book on May 26 2004, and ceased Octane2 production on June 25th, 2004. Support for the Octane2 was withdrawn in June 2009.

System Architecture

The Octane's system-board is designated as IP30. The system is based on SGI's Xtalk architecture. This means it does not use a system bus; instead it has a router Xbow that connects any two of its ports. One of the ports is used for the processor and memory subsystem, one is available for PCI (actually PCI-64) expansion and four are XIO slots (packet-based high-bandwidth bus, somewhat similar to HyperTransport). This makes it very similar to a single node of the SGI Origin 200 system.

The XIO is here and there bridged to PCI-64, using a chip named BRIDGE. The places where it happens include the system board (for the IOC3 multi-I/O chip, two ISP1040B SCSI controllers and RAD1 audio), MENET cards (four IOC3s) and the PCI cage (used for PCI cards in Octane). ARCS is provided as the boot firmware, similar to all contemporary SGI computer systems.

CPU Options

SGI Part Number Description
030-0888-004 R10000 195mhz 1mb Cache
030-0890-003 DUAL R10000 200mhz 1mb Cache
030-1138-002 R10000 175mhz 1mb Cache
030-1208-002 DUAL R10000 175mhz 1mb Cache
030-1271-002 DUAL R10000 225mhz 1mb Cache
030-1272-002 R10K 225mhz 1mb Cache-NL
030-1284-002 R10000 250mhz 1mb Cache
030-1286-002 DUAL R10000 250mhz 1mb Cache
030-1355-001 R12000 300mhz 2mb Cache
030-1356-001 DUAL R12000 300mhz 2mb Cache
030-1426-001 R10000 250mhz 2mb Cache REV3
030-1427-001 DUAL R10000 250mhz 2mb Cache R3.4
030-1432-001 R12000 270mhz 2mb Cache
030-1433-001 DUAL R12000 270mhz 2mb Cache
030-1475-00x 400mhz PM10
030-1476-001 400mhz PM20
030-1590-00x 360mhz PM10
030-1591-001 360mhz PM20
030-1591-002 360mhz PM20
030-1605-001 400mhz PM10 UPGRADE
030-1605-002 400mhz PM10 UPGRADE
030-1605-003 400mhz PM10 UPGRADE

Memory Subsystem

The Octane allows 256 MB to 8 GB of system memory, using proprietary 200-pin DIMMs. There are two system board revisions. The first revision (part number 030-0887-00x, usually distinguished by a black handle) only supports 2GB of RAM while the later one (part number 030-1467-001, with a silver handle) supports up to 8GB. The -0887 revision of the mainboard will work with all 32-128 MB DIMMS and the stacked variant of 256MB DIMMS, but not the later single-board version (SGI P/N 9010036). The memory subsystem has vast reserves of bandwidth that can be directly served by the Xbow router to any XIO card.

The Octane's memory controller is aptly named HEART. It acts as a controller between the processor, the memory (SDRAM) and the XIO bus.

Graphics Subsystem

Graphics on the Octane are provided by a series of cards: SI, SI+T, SSI, MXI. These are updated XIO versions of Solid Impact (SI), High Impact (SI+T) and Maximum Impact (MXI) from the SGI Indigo2 that were internally designated by SGI as 'MARDIGRAS'. The boards were accelerated and reengineered with faster geometry engine and texture modules to create their new versions: SE, SE+T, SSE, MXE. The SI/SE provides 13.5MB of framebuffer memory while the SSE and MXE have a 27MB framebuffer. The '+T' indicates an additional high speed RDRAM texture board which gives 4MB of texture memory, which is practically indispensable, though quite expensive and fragile. The SI/SE+T has one texture board while the MXI/MXE has 2 texture boards, however, the 2 boards in the MXI/MXE do not double the available texture memory to the system. It just doubles the texture performance.

Later Octanes and Octane2s support the VPro graphics board series, designated 'ODYSSEY'. The first VPro series cards were the V6 and V8. The main differentiator being that the V6 has 32MB of RAM (unlike the MARDI GRAS option, framebuffer memory and texture memory come from the same pool) and V8 having 128MB. Later, the V10 (32MB) and V12 (128MB) were introduced. The main difference with the new VPro V10/V12 series is that they had double the geometry performance of the older V6/V8. V6 and V10 can have up to 8MB RAM allocated to textures (2X more than the textured-enabled MARDIGRAS options), while V8 and V12 can have up to 108MB RAM used for textures.

The VPro graphics subsystem consists of an SGI proprietary chip set and associated software. The chip set consists of the buzz ASIC, pixel blaster and jammer (PB&J) ASIC, and associated SDRAM.

The buzz ASIC is a single-chip graphics pipeline. It operates at 251 MHz and contains on-chip SRAM. The buzz ASIC has three interfaces:

  • Host (16-bit, 400-MHz peer-to-peer XIO link)
  • SDRAM (The SDRAM is 32 MB (V6 or V10) or 128 MB (V8 or V12); the memory bus operates at half the speed of the buzz ASIC.)

As with the MARDIGRAS boards, all VPro boards support OpenGL in hardware (MARDIGRAS is OpenGL 1.1 + SGI Extensions, while VPro upgraded support to OpenGL 1.2) and OpenGL ARB imaging extensions, allowing for hardware acceleration of numerous imaging operations at real-time rates.

IMPACT Options

Option: Improved Option: GEs:
Geometry Engines
Raster Engines
Texture Modules
SI SE 1 1 none
SSI SSE 2 2 none
MXI MXE 2 2 2

Note: Only cards with texture memory offer hardware accelerated texturing, however you can add hardware texturing to TRAMless card by adding TRAM modules to it.

VPro Options

Option: Colour: RAM: Texture Memory (up to) Geometry Speed
V6 48bit RGBA 32MB 8MB Original GE speed
V8 48bit RGBA 128MB 104MB Original GE speed
V10 48bit RGBA 32MB 8MB 2X Faster GE speed
V12 48bit RGBA 128MB 104MB 2X Faster GE speed

Compatibility: The V6/V8 boards have been shown to work with any XBow version, but the V10/V12 boards do appear to require an XBow 1.4 frontplane. The official VPro upgrade docs, including SGI's system requirements, can be found on TechPubs. Forum threads on the topic can be found here.

More Information

More information about Octane graphics can be found on this page: Octane Graphics Boards

I/O subsystem

Octane series supports Ultra Wide SCSI devices and has two SCSI controllers. System can have up to three internal 3.5" SCSI SCA devices. Octanes use special mounting sleds for the harddrives which are compatible with Origin 2000, Origin 200 and Onyx2. The system also has external Ultra Wide SCSI bus.


What is the HEART?

The aptly named HEART is the core of the Octane. It integrates a SDRAM memory controller, a XIO device, an interrupt controller and a processor bus interface for up to four R10000-class processors.

Access methods

The HEART can be accessed in two ways from the processor. The first one is through the PIU (Programmed I/O Unit) at 0xFF0000 in processor physical address space. The other one is at widget 8 in XIO address space. The only one way available to other XIO devices is through the widget interface, so the Interrupt Status Set register is mapped there at address 0x80.

Memory controller

The HEART contains a SDRAM memory controller with ECC. ECC errors are signaled to the CPUs by interrupts.

XIO bridge

The XIO bridge is one of the main functions of the HEART. There are three access windows defined for each XIO widget number. There is a window at 0x10000000+ W*0x1000000 for widget number W, a window at 0x800000000+W*0x80000000 and a window at 0x1000000000+W*0x1000000000.

Note that XIO accesses are deeply pipelined by default. Due to that fact, writing to any XIO widget may not have any effect for several hundred cycles. To guarantee finalization of all posted writes it is required to read the widget flush register.

The XIO bridge in HEART provides also some Flow Control features for two channels. They allow to schedule a hiwater IRQ for any given XIO register address. If the register is an input to a FIFO, as is the case with the IMPACT graphics board, exceeding a prescribed number of writes to this register would cause a FIFO hiwater condition. As you already know, the XIO writes are posted and not immediately executed. Catching the hiwater condition in the HEART and not in the card allows to trap it in a more reliable way.

Interrupt controller

The HEART interrupt controller is visible from the PIU as a set of registers: interrupt mask registers for all processors (IMR[0:3]), an interrupt status register (ISR) and ISR clear and set registers that allow atomic manipulation of the ISR.

The XIO side consists of a single register 0x80 that can accept either an atomic ISR bit set command or an atomic ISR bit clear command. These commands cause asserting and deasserting IP[7:2] bits in the CPUs whose IMRs contain the bit in question.


A small part of the HEART is a programmable interval timer, consisting of 24-bit COUNT and COMPARE registers. The IRQ can be delivered only to the IP6 bit, which is the highest-priority CPU interrupt except internal CPU timer and HEART error IRQs. The timer counts at 12.5 MHz, every 8th internal HEART cycle (1/4th of the XIO frequency).


The HEART controls also the Number In a Can associated with processor modules. It features a standard SGI issue MicroLAN controller.

Audio subsystem

Audio hardware is standard; even without extensions they can support low-latency (3 ms input-to-output) audio streams. Alesis ADAT 8-channel, 24-bit optical ports are built-in, along with S/PDIF or AES/EBU optical and coaxial ports. This makes the Octane into a respectable digital audio workstation.

Available Operating Systems

Octane and Octane 2 are both supported by OpenBSD. Both single and dual CPU configurations are supported, however at this time there is no support for running X on the IMPACT or VPro framebuffers.

Linux runs on the Octane series, although the patch is quite experimental. Link to Linux/MIPS 2.6.12 kernel patch is available in the External Links section of the page. Both graphics versions are supported, and X Window System is available on the IMPACT series.

Add-On Options

- SCSI HardDisks:

     1. SGI IBM DDRS-34560 (4GB, 7,200RPM)
        (SGI P/Ns 013-2435-001, 064-0089-001)
     2. SGI IBM DDRS-39130W S95D (9GB, 7,200RPM)
     3. IBM DRHS COMP IEC-950 (36GB, 7,200RPM)
     4. Seagate Cheetah ST336706LC (36GB, 10,000RPM)
     5. Seagate Cheetah ST173404lCV (73GB, 10,000RPM)
     6. Seagate ST373453LC (73GB, 15,000RPM)
        (Labeled "TotalStorage by IBM" IBM P/N 24P3733)


     1. ACARD AEC-7722 ATAPI/IDE device on LVD (80MB/sec) SCSI bus. 

- SCSI Cards:

- SCSI PCI Cards:

     1. QLogic QLA1240D (HVD)
     2. QLogic QLA12160 (LVD)

- Fibre Channel Cards:

- Fibre Channel PCI Cards:

     1. QLogic QLA2200

- FireWire (IEEE-1394) Cards:

- Network Cards:

- Network PCI Cards:

     1. SGI p/n 9210289 (3C996B-T-SGI1)
     2. Any Tigon3 cards should work with this hack, these include Compaq NC7770, 3Com 3c996B-T (needs the B)

- CD-ROM Drives:

- SCSI CD-ROM Drives:

     1. Toshiba TXM3401E1 (does audio cd's, but requires caddies)
     2. Plextor UltraPlex 40x

- CD-RW Drives:

- SCSI CD-RW Drives:

     1. Plextor CD-R PX-R820T 1.08
     2. Plextor Plexwriter 12/10/32
     3. Sony CRX145S 10x4x32
     4. Yamaha CRW4416SX 4x4x16
     5. Yamaha CRW6416SX 6x4x16
     6. Yamaha CRW8424SX 8x4x24
     7. Yamaha CRW2200SX 20x10x40

- DVD-ROM Drives:

- SCSI DVD-ROM Drives:

     1. Pioneer DVD-304S (bootable)
     2. Pioneer DVD-305S (bootable)


- DVD-RAM Drives:

- SCSI DVD-RAM Drives:

     1. Matshita (Panasonic) LF-D291


     1. Archive Python 4324RP


     1. Seagate CTD8000H-S (says ***octane option*** on the label)


     1. HP C1537A DDS-3 Drive

- 3.5" Floppy Drives:

     1. Teac FD-235 HS

- Removable Drives:

     1. Imation LS-120 [SCSI]
     2. Iomega Zip 100 [SCSI]
     3. Iomega Zip 100 Plus [SCSI/Parallel]

- Magneto-Optical (MO) Drives:

     1. Fujitsu MCM3064SS
     2. Fujitsu MCM3130SS
     3. Fujitsu MCJ3230SS

A detailed bilingual guide by Diego A. De Giorgio [Generatrix] can be found here: The MOD/M.O.D. (Magneto Optical Drive) IRIX FAQ

- Scanners / Printers:

     1. Epson Perfection 636 [SCSI]

- Tablets:

     1. Wacom Intuos (serial interface)
     2. Wacom Intuos2 (serial interface)

- PCMCIA Card readers:

- SCSI PCMCIA Card readers:

     1. Adtron SDDS PC Card Drive [Caveat: You need to set the speed on the SCSI ID you're using to 5MB]

- Monitors [Sync-On-Green capable]

     1. Dell 2407WFP 1920x1200_60 V8 or V12 graphics (13w3>HD15 connection)
     2. Dell 2407WFP 1920x1200_60 V12 graphics w/DCD (DVI connection)
     3. Dell P991 (works with 13w3 adapter with pins pulled)
     4. SGI GDM-20D11 (standard 13w3 connection)
     5. SGI GDM-20E21 (standard 13w3 connection)
     6. Philips 170S (13w3>HD15 connection)
     7. Dell 2007WFP 1280x1024_60 on EMXI tested only (13w3>HD15 connection)
     8. LG Flatron L1732TQ 17" 1280x1024 (13w3>HD15 connection)

Note: Monitors on the O2 Hardware Aggregator should work on the Octane as well (though a MLA will be needed with the 1600SW)

- xDSL Modem/Router combos

     1. NogaNet TENDA TED8620R (Ethernet)

Case and Expandability

The Octane cases are large (W×H×D: 30×40×35 cm) and heavy (25 kg), yet there are no internal 5.25" drive bays, so external CD-ROM drives must be connected if desired. Extensions include video I/O, audio I/O, networking, realtime video compression boards, and external storage options (through SCSI, Fibre-Channel or Firewire). Octanes can use standard PCI cards with optional PCI cardcage aka 'shoebox' (which provides 2-full length and 1 half-length 5V PCI-64 slots), or a PCI to XIO adaptor (known as a 'shoehorn' which provides a single 3.3/5V 64-bit PCI slot).

Older Octanes can be upgraded with VPro graphics. The VPro Upgrade Installation Guide from Silicon Graphics states that V10 and V12 graphics board require an XBow revision 1.4 and Cherokee power supply. VPro V6 and V8 require a Cherokee power supply; any XBow revision will work. However, some users in the field have found that any version of VPro graphics will work with any power supply and frontplane. (Other users disagree.)

There's an easy way to (usually) identify the difference between Cherokee (747 W) and older Lucent (623 W) power supplies. The mounting handle is silver on the Cherokee International manufactured power supplies while the original Lucent manufactured ones have black handles. Unfortunately, the handles can become damaged and are very easy to replace, not necessarily with the original color. Caveat emptor.

Single-CPU Octanes and Octane2's can be upgraded to dual-CPU models by replacing the complete CPU module. Again, the official statements are that certain mainboards are required for certain CPU modules but this doesn't appear to generally hold up in the real world. Perhaps the SGI stated requirements came from early revisions of the relevant parts but no one in the hobbyist or reseller communities has yet reported a case where the official requirements were accurate.

Octane skins come in three types. The original Octane has green skins with the original 'cube' logo. The later model Octanes have skins the same colour as the original but with Octane2-style lettering and logos. Octane2 systems have blue skins with the current 'sgi' logo.

Parts compatibility between Octane and Octane2

Octane2 consists of different revisions of the Octane components, specifically a higher-wattage power supply, Xbow revision 1.4 in the frontplane, and an updated IP30 (part number 030-1467-XXX) The updated IP30 allows the use of higher-density memory modules (up to 8GB total RAM). The single-board 256MB DIMMs will not work in the older 030-0887-XXX mainboards, neither will the 512MB modules or any 1GB module.


LED Lightbar

Octanes came from the factory with two ways to illuminate the lightbar mounted in the front of their case - a red LED to indicate a fault, and a pair of small incandescent lightbulbs for normal operation. However these lightbulbs will eventually fail. A popular remedy is to replace them with diffrent colord LEDs rather than using another bulb. An external step-by-step procedure was created by Kurt Huhn here, and additional information can be found in this forum thread.


Front plane LEDs

The LEDs are simply link status lights. There is actually seven LEDs:

BaseIO X
    QA X X PCI Expansion
    QD X X QB
    QC X X Heart

The BaseIO and Heart are connected internally and are part of the IP30, so these will always be lit. The QA-QD refer to the quad module, which is labeled like this when facing the rear of the Octane:


QA should always be lit as the first graphics card is installed in Quadrant A. The other LEDs will be lit depending on what XIO options are installed.

The PCI Expansion LED will be lit if there is a PCI shoebox installed.

Dallas NVRAM

The Octane and Octane2 use the Dallas DS1687-5 for a real-time clock function and a few hundred bytes of battery-backed RAM.

Number In a Can (NIC) Replacement

Apparently the Number In a Can, or NIC, which stores the system serial number in many SGI workstations, can go bad and require replacement. On a single CPU module for the Octane this is a surface mounted 6-pin IC designated DS2505. It is possible to swap in the NIC from another module, as discussed in this thread.

External links