Systems

Indigo

Introduction

General

Indigo R4000 front with yellow R4000 Elan badge.

Of all the fantastic systems Silicon Graphics has produced in about 20 years this one seems to be one of the most favourite ones in the SGI users community. As a successor to the rather ugly Personal Iris series the Indigo is by many people still considered as SGIs best looking workstation (see for yourself in the Pictures section).

The Indigo R4000 was also the first SGI workstation that that featured the 64bit R4000 RISC CPU on the desktop, the first SGI in general using the new CPU was the Crimson. The Indigo offers builtin audio capabilities and comes in a very vell designed and space efficient chassis. With one of the Express graphics options it offers accelerated 3D graphics.

            R3000/33     R4000/100     R4400/150
----------------------------------------------------------
MIPS 30 85 120 (est.)
MFLOPS 4.2 16 22 (est.)
SPEC89 26 70 100 (est.)
SPECint92 22.4 59 82 (est.)
SPECfp92 24.2 61 86 (est.)

Models

Model CPU board CPU Chassis
Indigo IP12 MIPS R3000 30 MHz Mini Tower
Indigo R4000 IP20 MIPS R4000 100 MHz Mini Tower
Indigo R4400 IP20 MIPS R4400 150 MHz Mini Tower

 

History

Dates

1991, July
Indigo systems with R3000 processor announced. Read the official press release from 1991.
1992, January
XS and XS24 graphics options announced to ship in March, Elan to ship in April
1992, September
Indigo R4000 shipment announced for September 1992
1993, January
XZ graphics options announced to ship in January
1995, August
End of Production
2003, July
End of Service

4D/RPC

The Indigo was also referred to as the 4D/RPC or 4D/RPC-50 in case of the R4000 Indigo. The short story of that is that RPC is the abbrevation of RISC Personal Computer - see also the Indigo release announcement.

The ACE (Advanced Computing Environment) was an initiative to design a better PC by designing hardware and software compatibility standards. Members of the ACE group were beside Silicon Graphics among others also Compaq, DEC, Microsoft, MIPS or the Santa Cruz Operation (SCO). The NetBSD project has a documentation page on ARC systems which also includes a copy of the Advanced RISC Computing Specification (ARCS).

After the ARC platform failed to gain enough interest the consortium fell apart and Microsoft put a lot of the efforts made into Windows NT for which for a while also existed a port that was intended to run on MIPS machines.

A leftover of the ACE/ARCS days within the Indigo and the following SGI systems is an upgraded PROM ("ARCS PROM"). To quote man prom(1M): "The ARCS PROM offers the same functionality as previous PROMs, but in some cases with a different interface."

Soft Power Feature

SGI systems from Indy and Indigo 2 have a powerdown feature that runs along the lines of what PC users are used from ATX standard machines. The computer will try to shutdown gracefully when the power button is pressed and actual shutdown with switching off the power can be done in software.

The Indigo does not have this feature present in any variant that was sold to the customer. The interesting fact is that the feature apparently was planned during the design stage, but later on was trashed because of various technical problems. Once again Dave Olson has proven to be a great source for fun tidbits about SGI systems (source: <kt6t9cc@zuni.esd.sgi.com>):

Also, Indigo didn't have soft power (well, soft poweroff was designed
into the system, but didn't work right in the first run of systems, for
several reasons, so it was never enabled, and was designed out of later
revs). Indigo2 and Indy have soft power off, and an alarmclock poweron
mode (see man wakeupat).

Processor

IP12 Boards (R3000 Indigo)

CPU Board Processor Clockspeed Cache (d/i) Cache (2nd) Floating Point
IP12 / HP1 R3000A 30 MHz 32kb / 32kb none R3010 onboard

Indigo IP12 CPU board.

The IP12 board is a single board which includes the memory subsystem as well as the processor itself. There is no daughtercard needed for attaching the CPU as it is required for R4000 Indigo systems. The IP12 plugs into the CPU slot of the Indigo backplane.

On all Indigo systems the 'hinv' command does not show the true name of the used board. The 'hinv' output shows either IP12 or IP20 while the names in brackets (HP1, see above) are the actual names of the hardware components.

IP20 Boards (R4000 Indigo)

CPU Board Processor Clockspeed Cache (d/i) Cache (2nd) Floating Point
IP20 / HP2 R4000 100 MHz 8kb / 8kb 1MB R4000 onboard
IP20 / HP2 R4400 150 MHz 16kb / 16kb 1MB R4400 onboard

IP20 CPU board with R4400/150 CPU module (modified heatsink).

On R4000 Indigo systems the processor is on an additional module which is attached to the CPU board itself. Originally it was planned to offer more CPU options for the Indigo but in the end the R4400/150 has been the top of the line for the Indigo. The IP20 board is plugged into the CPU slot of the Indigo backplane.

On all Indigo systems the 'hinv' command does not show the true name of the used board. The 'hinv' output shows either IP12 or IP20 while the names in brackets (see HP2 and PM1/PM2 above) are the actual names of the hardware components. Some versions of 'hinv' (in the PROM) also show the external clock rating of the CPU. While this is not exactly wrong, it is confusing as the systems were put to the market as "100MHz" and "150MHz" not "50MHz" and "75MHz" machines.

Memory

IP12 Boards (R3000 Indigo)

The memory subsystem on the R3000 Indigo is the same that was also used on 4D/30 and 4D/35 Personal Iris models. It thus uses the same type of memory modules. Unlike the Personal Iris the Indigo has only space for three instead of four sets of modules.

Type:                   proprietary SIMMs
Sockets:                12 (3 * 4 sockets)

Minimum configuration:  16 MB (4 * 4 MB SIMMs)
Maximum configuration:  96 MB (12 * 8 MB SIMMs)

The following chart shows the layout of the socket groups on the board. When you populate the board you always need to fill a group (A, B or C) with 4 SIMMs of one type. You can mix SIMM types between these groups, but not within. The R3000 Indigo supports 2, 4 and 8MB memory modules. Due to a bug in the hardware it is not possible to use more than one kit consisting of 4 MB modules (16 MB total).

                                                |
     ##A1################ ##A3################  |
     ##A2################ ##A4################  |
     ##B1################ ##B3################  |
     ##B2################ ##B4################  |
     ##C1################ ##C3################  |
     ##C2################ ##C4################  |
________________________________________________|

IP20 Boards (R4000 Indigo)

Type:                   36bit wide 72pin SIMMs (fast page mode, parity, 70ns) 
Sockets:                12 (3 * 4 sockets)

Minimum configuration:  8 MB (4 * 2 MB SIMMs)
Maximum configuration:  384 MB (12 * 32 MB SIMMs);

The following chart shows the layout of the socket groups on the board. When you populate the board you always need to fill a group (S?A, S?B or S?C) with 4 SIMMs of one type. You can mix SIMM types between these groups, but not within. The R4000 Indigo is known to support 4, 16 and 32 MB memory modules.

                                                |
     ##S1A############### ##S3A###############  |
     ##S2A############### ##S4A###############  |
     ##S1B############### ##S3B###############  |
     ##S2B############### ##S4B###############  |
     ##S1C############### ##S3C###############  |
     ##S2C############### ##S4C###############  |
________________________________________________|

Interesting fact: On the first systems that did support the R4000 processor the maximum memory configuration was not supported. The useable amount of memory was 128 MB on IRIX 4.0.5F, 256 MB on IRIX 4.0.5IOP ("Indigo Only Patch") and finally 384 MB on IRIX 5.1 and above.

Graphics

Overview

These graphics options apply to both variants of the Indigo - R3000 and R4000. The graphics options are plugged into a separate graphics slot of the Indigo backplane.

  • no graphics - server version of the Indigo systems
  • Entry Level Graphics (aka Starter Graphics)
    LG1 and LG2 graphics board
  • Express Graphics Family
    XS8, XS24, XS24Z, XZ and Elan boardsets

Other

Audio

On both kinds of the Indigo Audio is provided by onboard hardware on the IP12 or IP20 board which is designed around a Motorola 56000 DSP (Digital Signal Processor). This DSP has been popular in other IT equipment as well (NeXT, Atari Falcon) and descendants of the design are in use still today in audio gear or communication devices.

See the connectors bit below for audio ports offered on the Indigo.

Drives

All Indigo systems have one narrow SCSI channel which can be accessed either via an external Centronics style 50pin connector or the internal drivebays (sled required). All the usual rules regarding SCSI apply. Up to 7 devices can be attached, three of them can be put into the internal drivebays. Termination on the internal end of the SCSI bus is handled automatically, on the external port proper termination must be applied. See Chassis for details on the internal drivebays. The SCSI chipset used is a Western Digital 33C93B Fast SCSI controller.

Connectors

  • Multimedia:
    5 stereo 1/8" phone jacks, for headphone, microphone, speakers, etc.
  • Networking:
    15 pin AUI network connector (Thick Ethernet)
  • Input/Output:
    1 Mini-DIN 6 pin port for proprietary keyboard/mouse
    2 Mini-DIN 8 pin Mac compatible serial ports
    Centronics style SCSI connector (Narrow SCSI)
    DB25 parallel port
  • Video:
    13W3 connector
    HD15 VGA (Entry Level graphics only)
    BNC Genlock, Mini-DIN 3 pin 3D (Express graphics only)

Expansion Slot

The R3000 Indigo has two GIO32 expansion slots, the R4000 Indigo two GIO32bis slots on the CPU board that can be used for additional hardware (see options). But as it is a proprietary system there is not much around aside from a couple of things that SGI and very few other vendors have made.

Options

Network

  • ATM (Fore Systems)
  • Ethernet
  • Fast Ethernet (Phobos G100, Phobos G130, Set Engineering)
  • FDDI
  • Token Ring

Video

Other

  • GIO-VME interface (Bit3 Model 607)
  • SCSI interface (WD93 based narrow SCSI)

Chassis

The Indigo comes in a solid metal chassis that is hidden underneath indigo colored plastic skins. Every standard Indigo has the following dimensions:

    width:     25 cm /  9.84"
    height:    38 cm / 14.96"
    depth:     28 cm / 11.02"
     
    weight:    17 kg (R4000 incl. 1 drive + Elan graphics)

All Indigo systems have three drivebays for internal 3.5" SCSI devices that have to be mounted on special drivesleds to be used in the systems. The upper two of them can be accessed from the outside through a small door which makes them useable for removeable media drives. To remove any of the three drives the frontplate has to be removed which is impossible if the system is secured with the locking bar.

The skins of the Indigo are colored in a dark blue which has a decent hint of purple to it. On R3000 Indigos the type of the graphics option the machine was shipped with was printed on the front door. On R4000 a small badge was used that in addition to the name of the graphics option included "4000" to denote the faster CPU type.

Specials

VME Indigo

There was a VME based versions of the Indigo (V50), that could be used with the VME version of the Express graphics hardware. The VME version was composed of at least two boards: The first contained the CPU and external IO (keyboard/mouse, serial, parallel, ethernet, SCSI), while the second contained the VME controller, GIO-over-P2 logic, and up to 64 MB of RAM. A third card for memory expansion could be added to the V50.

Rebadged Systems

A Indigo in Siemens Nixdorf design.

Relabeld Indigo systems were available from several companies, the most common being

  • Control Data: Blue skins with Control Data logos painted on the front. The basic color is the original Indigo color.
  • Siemens Nixdorf: Gray skins with Siemens Nixdorf logo (RW320 = R3000 Indigo, RW420 = R4000 Indigo).

Unlike the VME Indigo the Rebadged Systems have exactly the same dimensions as the original systems.

Special Configurations

Cyclone Indigo: Raster Image Processor from Colorbus Corp. The system was a stock Indigo but had one GIO slot occupied by the interface card for a color copier or printer.

Espressigo

The Espressigo is a Gaggia espresso maker in Indigo skins. SGI Germany had a leaflet similar to the ones that were made for the actual computers. According to the leaflet the Espressigo features a 50 MHz Gaggia CPU (coffee processing unit), 30 ml primary coffee cache, 1,5l secondary water cache, etc. There is even a price tag, 1.790 DM (excluding tax).

Here is a website (in german) which shows higher quality pictures of the Espressigo.

Problems

Operating System

Choosing an operating system.

The Indigo when first introduced was based on the R3000 microprocessor. Support for this system was added to 4D1-4.x from beginning on (4D1-4.0). Support for Elan, XZ and XS graphics was added shortly thereafter in 4D1-4.0.2. Next support for the new R4000 based model was added in 4D1-4.0.5E.

General support for the Indigo can be found in the all platform releases of IRIX 5.x. Only the R4000 models were supported by IRIX 6.2 and IRIX 6.5. The support for the remaining legacy systems like the Indigo R4000 was dropped after 6.5.22 making IRIX 6.5.22 the last version to support any of these systems.Choosing an appropriate IRIX release for the Indy is dependant on the CPU and the amount of memory installed:

Choosing an IRIX release for the Indigo depends on the amount of memory as well as the processor installed.

  < 128 MB >128 MB
R3000 CPU IRIX 5.3 n/a
R4000 CPU IRIX 6.2 IRIX 6.5.22

Battery Failure

Signs of failure: The system fails to boot and repeats the message "Can't set tod clock"

This error is very common these days and it occurs during boot time. It usually means that the onboard battery is empty and that the system can't set it's clock. It is not fatal and some systems even recover when they are run for a while. This error does not occur while the system is running.

The original battery used is a Tadiran TL-5186 3.6V battery. Current replacements are the Sonnenschein SL-340 or SL-840. Both can be installed in the same place as the original battery of the Indigo. Have a look at the somewhat outdated Battery Replacement FAQ.

In the long run a cheaper solution is to wire a socket for a generic button cell to the battery connectors on the main board. The socket could be fixed on one of the GIO32 bus placeholders. The Indigo will work just fine with a standard and much cheaper 3 V button cell (like a CR2032).

Revision C Memory Controller

Signs of failure: While booting the system displays a message like "Warning: Revision C Memory Controller (MC) chip needed in order to properly operate with SIMMS of this type."

When upgrading memory on an R4000 Indigo IRIX might issue the above warning if there is no Rev C memory controller installed in the system (you can check using /usr/gfx/gfxinfo). If all memory is detected (i.e. shown in hinv) and you are not experiencing unusual problems with the system since the upgrade it should be safe to ignore the message. It was added when there were bugs in some memory modules. The upgraded Rev C memory controller contains a workaround for these bugs, but as these have also long been fixed there should be no problems today - even with older MCs.

In later IRIX the warning message has been worded differently: "WARNING: You may need a memory controler revision C because of the type of simms installed. If you don't experience any memory errors you won't need MC revision C"

4MB Memory modules

Signs of failure: System doesn't work when more than one set of 4MB modules is installed.

This is a known problem and a flaw in the systems hardware which can not be fixed. The bottom line is, that only one 16MB kit (4x4MB) may be installed - there is no limitation regarding 8MB (4x2MB) or 32MB (4x8MB) kits.

Bad eaddr

Signs of failure: The system complains about a bad ethernet address (ff:ff:ff:ff:ff:ff).

In general this means that the EEPROM that contains the hardware ethernet address is dead or contains invalid data. It is an 8 pin MiniDIP serial EEPROM (93C56) which is socketed on the backplane.

In many cases the reason is, that in the Indigo different CPU boards (IP20, then IP12) were used. The location of the adress is different between the two boards and is properly relocated when a system is upgraded from IP12 to IP20. When the IP12 is placed back in the system the MAC address is erased.

A possible solution is to place the IP12 in the system and reset the mac adress from the PROM monitor using the eaddr command - the IP20 doesn't allow that. After that the system can be used with the IP12 board or upgraded to IP20 which will relocate the address once again.

Parts

Nr Name Description
030-0246-00x FDDI Controller (GIO32)
030-0528-00x Token Ring GIO32
030-0591-00x Ethernet E++ GIO32
030-7005-00x Ethernet GIO32
030-8044-00x HP1 Indigo R3K Mainboard
030-8050-00x Indigo Backplane
030-8077-00x LG1 Indigo Entry Graphics
030-8095-00x SRV1 Starter Video
030-8096-00x HP2 Indigo R4K Mainboard
030-8097-00x PM1 Indigo 2 R4000SC/100 PM1 also available in Indigo
030-8112-00x Galileo Video
030-8116-00x PM2 Indigo 2 R4400SC/150 PM2 also available in Indigo
030-8202-00x HP1 Indigo R3K Mainboard
030-8216-00x FDDI Controller GIO32
040-8067-00x Indigo Lockbar
050-8000-00x Indigo Drivesled
9150800 Indigo Mouse
9430810-A Indigo Powersupply
9430812-A Indigo Powersupply
9500801 Indigo Keyboard

Pictures

Indigo R4000 Elan with Galileo Video

Indigo R4000 with Galileo breakout box.

Indigo with frontcover removed.

Cardcage door opened revealing the CPU and GFX boards.

Back of an Indigo with Elan graphics and Galileo video board.

IP20 CPU board with R4400/150 CPU module.

Indigo Elan Graphics, covered by Galileo Video board (IEV1).

Galileo Video (IEV1) board on Elan Graphics boardset.

Galileo Video breakout box.

Indigo R4000 Elan

Indigo R4000 front with yellow R4000 Elan badge.

Indigo front door opened revealing acess to the drivebays.

Indigo with frontcover removed.

Cardcage door opened revealing the CPU and GFX boards.

CPU and GFX boards removed.

Back of an Indigo with Elan graphics and a Chyron Centaur video board.

IP20 CPU board with R4400/150 CPU module. A Chyron Centaur board is installed in the GIO32 slots.

IP20 CPU board with R4400/150 CPU module. A Chyron Centaur board is installed in the GIO32 slots.

Indigo Elan Graphics

Indigo Elan Graphics

Option drive on an Indigo drivesled.

Option drive on an Indigo drivesled.

Closeup of the connector on the drivesled.

Indigo R4000 Entry

Indigo R4000 without badge.

Frontcover removed from Indigo.

Indigo interior with CPU and GFX board.

Back of an Indigo with Entry graphics and IP20 CPU board.

IP20 CPU board with R4400/150 CPU module (modified heatsink).

IP20 CPU board with R4400/150 CPU module (modified heatsink).

LG1 Entry / Starter graphics.

LG1 Entry / Starter graphics.

Indigo R3000 Entry (SNI Design)

A Indigo in Siemens Nixdorf design.

Siemens Nixdorf Indigo with frontcover removed.

Cardcage access opened, revealing the CPU and GFX boards plus some cludge in the drivebay.

Back of a Siemens Nixdorf Indigo. Boards installed are Entry graphics and IP12 CPU board.

Indigo IP12 CPU board.

Indigo IP12 CPU board.

LG1 Entry / Starter graphics with Song and Dancing machine logo.

Links

SGI Press Releases

  • 1991, July - Silicon Graphics Introduces New RISC Personal Computer [local]

Manuals

For additional documentation on software, optional hardware or upgrading instructions see SGIs technical publications library.

Articles

  • An SGI catalogoue from approx. 1994 featuring pictures (DIN A4 fullsize) and short german descriptions of Indigo, Indigo 2, Crimson, Onyx, Challenge and Power Challenge: Page 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 (numbers refer to the original page number, not the filename; Scan by Ganjatron)
  • Byte article: The big guns are still around, but Intel's processor advancements--along with the success of the Wintel platform--made the ACE consortium obsolete

FAQ

  • Versions FAQ - how to determine what type of Indigo you are looking at.
  • Battery FAQ - some hints on solving the "can't set tod clock" problem.

Technical Papers

  • Indigo Technical Report [local]

Websites