SGI Indy

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SGI Indy Workstation

Introduced in 1993, the Indy was the fruit of SGI's effort to muscle into the market for desktop publishing, low-end CAD, and multimedia. At the time, the market was mostly dominated by Apple. The Indy was the first computer to include a digital video camera, and was built with a (then) forward-looking architecture including an on-board ISDN adapter. With the inclusion of analog and digital I/O, SCSI, and standard composite and S-Video inputs, the Indy really was a multimedia machine.

The Indy was superseded by the O2 in 1996.

Physical Characteristics

Indy with cover removed

The Indy packed a large number of features into a compact (41 cm × 36 cm × 8 cm), simple, and elegant package. Standard features included an Indycam webcam, 10MB/s Fast SCSI, 10Mb/s ethernet, ISDN, PS/2 keyboard and mouse ports, two serial ports, a parallel port, onboard audio, and VINO video inputs (see below). One unusual option for the Indy was an Insite floptical drive. The floptical used 21 MB optical diskettes, but could read and write standard 3.5" magnetic floppies as well.

The sturdy, pastel-colored "pizza box" chassis is comparable to Sun's SPARCstation systems of the same era, and is designed to fit underneath a large CRT monitor. It can accommodate two internal 3.5" SCSI drives and two levels of expansion cards. With all cooling accomplished via a single fan at the rear of the power supply, the Indy is a relatively quiet system, and it has modest power requirements.

The Indy chassis was also used in the Silicon Graphics Challenge S, an entry-level server system.


180MHz R5000 CPU

Indy's motherboard has a socket for the Processor Module (PM). Early Indys used the 100 MHz MIPS R4000 CPU, which quickly proved inadequate. The Indy, at the bottom of SGI's price list, thus became the primary platform for MIPS's low-cost, low-power-consumption R4600 CPU series. The R4600 had impressive integer performance, but had poor floating-point capability. This, however, wasn't too huge of a problem in a box that was generally not designed for floating-point-intensive applications. For this reason, the R4600 made an appearance outside the Indy line just once, and only briefly, in the SGI Indigo2. This series of CPU issues, along with the relatively low-powered graphics boards, lower maximum RAM amount, and relative lack of internal expansion ability compared to the SGI Indigo led to the Indy being pejoratively described amongst industry insiders as "An Indigo without the 'go'."

The R4600 chip itself has no L2 cache controller, external controller was used to add 512K of L2 cache. R4600s processor modules both with an L2 cache (SC) and without (PC) are common in the Indy. At the same clock rate, the SC version of the processor module is generally 20 to 40 percent faster than the PC version, due to the memory cache.

The Indy was also the first SGI to utilize the MIPS R5000 CPU, which offered significant advantages over the R4400 and R4600 it replaced. The Indy's 180 MHz R5000 module can be overclocked to 200 MHz by replacing its crystal oscillator chip.


The Indy can accommodate up to 256MB of RAM via eight 72-pin parity SIMMs. At the beginning of its life, the Indy shipped with only 16MB of RAM. IRIX 5.1, the first Operating System for the Indy, did not take full advantage of the hardware due to inadequate memory management. SGI realized this and quickly increased the base specification to 32 MB, at considerable cost. Subsequent IRIX releases made huge improvements in memory usage. The latest release of IRIX available for the Indy workstations is 6.5.22.


Three graphics subsystems were available for the Indy: 8-bit XL, 24-bit XL, and 24-bit XZ. Each supported a resolution of 1280 × 1024 at a refresh rate of 76 Hz, and had a Sun Microsystems-style 13W3 monitor connection. All of these graphics options use a 32-bit GIO32 bus to interface with the system.

The first two boards are referred to by the code names "Newport", "NG1", or "XL", depending on which version of the marketing or reference material you read. They are comprised of a single GIO32 board, and are essentially the same except for the number of RAM chips soldered to the board.[1]

NG1 is probably an acronym for Newport Graphics 1. XL is also used to refer to similar graphics subsystems in other SGI workstations (notably the Indigo2), with the implication that their performance characteristics should be similar.

One exception to this naming scheme came with the introduction of the R5000 microprocessor. An R5000 CPU can perform 3D geometry calculations faster than the XZ subsystems's two Geometry Engines--as a result, all 3D is done in software. XZ graphics were rarely paired with the R5000 for this reason. To emphasize the enhanced performance provided by the R5000's new instruction set, the product was referred to as "XGE" instead, although the hardware was identical.[2] The label "XGE" was simply another example of the disconnect between marketing material and actual engineering design. "XGE24" was another name for 24-bit XL graphics on an R5000 system.[3]

A rare option associated with the Newport graphics line was the ability to add a second graphics card (resulting in a dual-head configuration) to the Indy. Functionally, the dual-head boards were the same as two normal XL 8- or 24-bit boards, but the set of two boards were specialized such that the GIO32 connectors were located in physically different places from normal Newport boards.[4] The board mounted closest to the motherboard is different, while the top/second board is a normal Newport board.

The third type of graphics board was the "XZ", explained below.

8-bit XL

Also known as Newport graphics, these were designed for general 2D X11 applications; no hardware 3D acceleration was included. These worked best for 2D CAD or general office use.

24-bit XL

Using an identical circuit board as the 8-bit XL, the 24-bit XL included three times as much framebuffer memory to accommodate 24-bit color. A popular choice for some general graphics work, since its 2D performance is better than the XZ card.


XZ Graphics for Indy

These graphics were a port of the Indigo²'s XZ (Elan) graphics into Indy - they offered very good non-textured 3D performance at the time, sacrificing a bit of 2D performance in return. The XZ graphics option was not widely used in Indy systems that used the R5000 CPU. This was mostly due to extensions of the MIPS instruction set that were implemented in the R5000. With the new instructions, the R5000 CPU could perform coordinate transformations faster than the XZ graphics board. Because XZ graphics only provided assistance to the main CPU for coordinate transformations, 3D rendering was often faster when implemented only in software. However, using XZ to perform coordinate transforms does free the CPU to perform other rendering-related calculations. These graphics take the form of two boards, one on top of the other, and occupy one GIO slot. It is not possible to install any other GIO option boards while the XZ boards are installed.


Indy Video option board

The Indy was the first SGI to have video inputs by default. Every Indy has a composite, S-Video, and digital video input built into the motherboard, which are collectively known as "Vino" (video input, no output) video. None of them are of professional quality, but are still usable. The digital input is a proprietary D-sub connector with a rectangular array of pins, and is used by the SGI IndyCam. The connector is the same as serial ports on Cisco routers, however is electrically different.

The maximum supported input resolution is 640x480 (NTSC) or 768x576 (PAL). It takes a fast machine to capture at either of these resolutions, though; an Indy with slower R4600PC CPU, for example, may require the input resolution to be reduced before storage or processing. However, the Vino hardware is capable of DMAing video fields directly into the framebuffer with minimal CPU overhead.

None of the Indys support video output by default - that would require the Indy Video GIO32 card. In addition, there is an optional video module called CosmoCompress, which offers realtime JPEG video compression and decompression and uses up another GIO32 slot.


The Indy has two drive bays for 1-inch tall 3.5" drives. The upper drive bay is externally accessible and may hold a SCSI floptical drive. All external and internal drives share a single Fast SCSI bus (unless a GIO32 SCSI card has been installed).


External CD-ROM drive connect via SCSI connector at rear side of the box. Typical drive supports boot, OS install, audio. Special ROM is required to boot from for certain device types. [5] A small number of CD-ROM drives have the firmware needed to do audio over SCSI.


All Indys shipped with Attachment Unit Interface (AUI)/10BASE-T Ethernet and ISDN as standard equipment. The Ethernet ports are half-duplex only. The 10BaseT port takes precedence over the AUI port - if the system detects a carrier on both ports, it will use the 10Base-T.

Two different manufacturers produced 100BASE-TX Ethernet cards compatible with the Indy, both of which attached to the system using the GIO32 bus. Set Engineering produced one such fast ethernet card, based on the Texas Instruments ThunderLAN chipset, under contract with SGI. In addition, Phobos also produced two models of fast ethernet cards for the Indy (the G100 and G130).

The ISDN port provided on the Indy has no NT1. An external NT1 is required to use the ISDN port in North America.

Continued use

The component of the Indy most prone to failure is the Nidec/Power General power supply. New power supplies are manufactured by Sony and sold through resellers, however they are expensive.

The Indy's Ethernet address, which doubles as the system's serial number, is stored in battery-backed RAM. This means that when the internal battery dies, so does the system - it will hang at the PROM monitor and refuse to boot any further as a result of the Ethernet address being all FFs. A non-amateur user can replace the PROM battery and reprogramme it. The original battery was made by Dallas Semiconductor, now owned by MAXIM. The original unit was marked the "DS-1386-8K-150", however its replacement unit, the "DS-1386-8K-120" can be directly substituted with no ill effects.

One can set a new MAC address from the Command Monitor with the command "setenv -f eaddr xx:xx:xx:xx:xx:xx". The -f switch here will force the new MAC address. The MAC address is (usually) on a sticker to the rear of the unit, and hence can be reprogrammed without losing software licences, which often rely on it to verify ownership. Otherwise, any MAC address in SGI's block is usable.

(Originally based upon Alex's SGI page (PageMirror), public domain as of September 7 2003)

See also this note in the IRIX for Indy and Challenge S page

IRIX for Indy and Challenge S#Corrupt MAC addresses

See also

External links