SGI Octane

The Octane and the similar Octane2 are IRIX workstations marketed by SGI. Both are two-way multiprocessing-capable workstations, originally based on the MIPS Technologies R10000 microprocessor. Newer Octanes are based on the R12000 and R14000. The Octane2 has four improvements compared to Octane, a revised power supply, system board and Xbow. The Octane2 also shipped with VPro graphics and supports all the VPro cards. Later revisions of the Octane also included some of the improvements introduced in the Octane2. The codenames for the Octane and Octane2 are "Racer" and "Speedracer" respectively.

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

A new system named Octane III was introduced in early 2010. The Octane III is an Intel Xeon-based desk-side cluster system and should not be confused with the Octane and Octane2.

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 Crossbow application specific integrated circuit (ASIC), referred to as Xbow, a dynamic crossbar switch that connects the XIO ports to the hub. One of the ports is used for the processor and memory subsystem, one is available for PCI-X 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 Origin 200 system.

The XIO could be bridged to PCI-X, using a chip named BRIDGE. This bridging included 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). The Octane uses ARCS boot firmware, like all contemporary SGI computer systems.

Processors overview

Processors for Octane series computers:

Processor:	Cache:	Single (MHz):	Dual (MHz):
R10000SC	1MB	175, 195, 225, 250	175, 195, 225, 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. A second CPU cannot be added; the only option is to replace the whole CPU module.

Memory subsystem

The Octane supports 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) supports 2 GB of RAM, while the second (part number 030-1467-001) allows up to 8 GB. 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 was 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, 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 Rambus RDRAM-based 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 Octane2's support the SGI 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 MARDIGRAS 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.)
PB&J ASIC

As with the MARDIGRAS boards, all VPro boards support the OpenGL (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 Series

Option:	Improved Option:	GEs: Geometry Engines	REs: Raster Engines	Texture: Texture Modules
SI	SE	1	1	none
SI+TRAM	SE+TRAM	1	1	1
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 Series

Model	Colour depth	Memory	Texture memory (maximum)	Geometry engine speed
V6	48-bit RGBA	32 MB	8 MB	Original
V8	48-bit RGBA	128 MB	104 MB	Original
V10	48-bit RGBA	32 MB	8 MB	2× original
V12	48-bit RGBA	128 MB	104 MB	2× original

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.

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 adapter (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 SGI 'cube' logo. The later model Octanes have skins of the same colour as the original, but with Octane2-style lettering and logos. Octane2 systems have blue skins with the modern lowercase letter-only SGI logo.

I/O subsystem

Octane series has two SCSI controllers that supports Ultra Wide SCSI devices. Systems can have a maximum of three internal 3.5" SCSI SCA devices, using proprietary mounting sleds that are also compatible with the Origin 2000, Origin 200 and Onyx2. An external Ultra Wide SCSI port is used for connecting external devices.

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 experimental. Both IMPACT and VPro graphics are supported, and the X Window System is available on the ImpactSR series.

OpenBSD has a port that runs on the Octane series as well.

External links