SGI Octane
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Image:SGI Octane 2 closeup.png
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 Support for the Octane2 will be withdrawn in June 2009.
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System architecture overview
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.
Processors overview
Here's a table of processors that have been available for Octane series.
| Processor: | Cache: | Single (MHz): | Dual (MHz): |
| R10000SC | 1MB | 175, 195, 225, 250 | 175, 195, 250 |
| R12000SC | 2MB | 270, 300, 400 | 270, 300, 400 |
| R12000SCA | 2MB | 360, 400 | 360, 400 |
| R14000SCA | 2MB | 550, 600 | 550, 600 |
The Octane series has single and dual CPU modules. You cannot add a second CPU, so the only option is to replace the whole module.
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 030-0887-003, easily distinguished with its black handle) only allows 2GB of RAM, while the later one (part number 030-1467-001, with a silver handle) allows up to 8GB. 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 bridge 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, SSI+T, MXI. These are updated XIO versions of Solid Impact (SI), High Impact (SSI) and Maximum Impact (MXI) from the SGI Indigo2 that were internally designated by SGI as 'MARDIGRAS'. The boards were accelerated and reengineered to create their new versions: SE, SE+T, SSE, SSE+T, MXE. The '+T' indicates an additional high speed Rambus RDRAM-based texture board, which is practically indispensable, though quite expensive and fragile. Later Octanes and Octane2s support the SGI VPro graphics board series, designated 'ODYSSEY'.
The details of the gfx subsystem are not known, however it is clear that (after loading correct microcode to the Geometry Engines) it implements OpenGL directly in hardware. This, and the fact that the card sports a programmable DMA engine (in the HQ4 bus interface chip) helps offload the processor of most graphics-intensive tasks.
IMPACT Series
| Option: | Improved Option: | GEs: Geometry Engines | REs: Raster Engines | Texture: Texture Modules |
| SI | SE | 1 | 1 | none |
| SI+TRAM | SE+TRAM | 1 | 1 | 2 |
| SSI | SSE | 2 | 2 | none |
| MXI | MXE | 2 | 2 | 4 |
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 Series
| Option: | Colour: | RAM: |
| V6 | 48bit RGBA | 32MB |
| V8 | 48bit RGBA | 128MB |
| V10 | 48bit RGBA | 32MB |
| V12 | 48bit RGBA | 128MB |
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 digtal audio workstation.
Case and expandability
The Octane cases are large (WxHxD: 30x40x35 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 (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 however V10 and V12 graphics board require xbow revision 1.4 and Cherokee power supply. VPro V6 and V8 require xbow revision 1.3 and Cherokee power supply. There's distinct difference between Cherokee (747 watt) and older Lucent (623 watt) power supplies. Mounting handle is silver in the Cherokee International manufactured power supplies while the original Lucent manufactured ones have black handles.
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 a modern 'sgi' logo.
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 Onyx 2. System also has external Ultra Wide SCSI bus.
Available Operating Systems
The SGI Octane with IMPACT-class graphics was first supported by IRIX version 6.4. VPro-class graphics have been supported since IRIX version 6.5.10 for V6 and V8, with V10 and V12 graphics supported as of 6.5.11 (or 6.5.10 with a special driver patch).
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 ImpactSR series.