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Difference between revisions of "Number In a Can"

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* Chip 1: Dallas DS 1982
* Chip 1: Dallas DS 1982
** It's called the System Identification Module and it's actually a DALLAS DS1982 "iButton" [[EEPROM]] which contains the system ID number.  
** It's called the System Identification Module and it's actually a DALLAS DS1982 "iButton" EEPROM which contains the system ID number.  
* Chip 2: Atmel 24c04.
* Chip 2: Atmel 24c04.

Revision as of 23:01, 16 September 2018

NIC is the abbreviation for Number In a Can. Dallas Semiconductor which today is part of Maxim Integrated Products chose this perhaps not very fortunate name to describe the iButton 1-wire devices used for hardware identification on SGI Origin, SGI Octane and later systems. Most later "NICs" are not really metal cans, but small 6-pin SMD chips, usually DS2505 ones (the exceptions are MAC NICs on IP27 systems and IOC3 PCI and MENET XIO cards, which use DS1981U NICs and IP30 systems which use a DS2502).

A NIC contains a 64-bit unique address that is used to identify it inside a system and possible some OTP (One-Time Programmable) EPROM. The unique address is not used for anything by SGI software. However, the OTP memory contains important information on the device containing the particular NIC:

  • 6 bytes at 0x05: serial number in ASCII
  • 9 bytes at 0x15: part number in ASCII (xxx-xxxx-)
  • 3 bytes at 0x23: revision in ASCII (xxx)
  • 10 bytes at 0x34: readable name of the device (in ASCII, naturally)

Each 32-byte page of the device is protected by a 16-bit CRC in accordance with Dallas recomendations. Also, the page redirection table is used by SGI to keep track of hardware revision updates (very prominent on early IP30 system boards, as there is a hand-soldered wire running over the whole board).

NICs were introduced with the O2/Octane/Onyx2 generation of systems. Everything older than that used the MAC address of the (first) ethernet port. The exception is the Onyx1 which stores the serial number in battery backed NVRAM on the system controller and IO4.

  • O2 has a NIC on the PCI riser. Looks a bit like a transistor. This number is also the MAC address which is why the O2 cannot initialize the network when the PCI riser is missing. This is a convenient way to keep the serial number intact even when just about any part of the O2 is replaced or upgraded.
  • Crimson (and other 4D PowerSeries and older) use the MAC address of the ethernet port on the IO2/IO3/IO3B board.
  • Personal Iris uses the MAC address, the ethernet chip is on the system board.
  • Indy stores its MAC address in a DSxxxx battery backed RTC/NVRAM. It can be reprogrammed from the PROM monitor.

These NICs aren't network boards, they're small SEPROMs that look like lithium batteries. They can be removed and swapped if you need to replace the part they're on or want to change your serial number for another reason.

  • Origin200 = NIC the MSC (system controller board, the part with the buttons on it under the 5.25" bays)
  • Octane = NIC on the frontplane board.
  • Indigo2 8-pin DIP ROM on the serial/keyboard port riser board.
  • Indigo: on the backplane
  • Personal IRIS: 8-pin DIP PROM on the board with the power and fault LEDs.
  • Indy: stored in the Dallas chip in a similar fashion to the Sun hostid. It is equal to the Ethernet MAC address listed on the back yellow/orange label if you need to reset it.
  • Onyx/CHALLENGE: The hostid/serial number is stored on the system controller in a Dallas chip. Can be reprogrammed using the PROM monitor
  • Fuel DS1742W-120
  • Tezro = ?

Big iron has "Snnnnn" format system serial numbers, workstations simply use the MAC address. For everything older than the Onyx1 the system serial number is unrelated to the hostid used to nodelock licenses.

Error message if loose or missing

  • Octane:
       nic_eaddr: Failed to find redable MAC NIC, rc 1
  • Onyx2 deskside:
       Checking hardware inventory ...............
       Warning: Inventory table ID value is 0. Check Midplane NIC


  • Chip 1: Dallas DS 1982
    • It's called the System Identification Module and it's actually a DALLAS DS1982 "iButton" EEPROM which contains the system ID number.
  • Chip 2: Atmel 24c04.

FrontPlane.gif Octane (AKA System identification module)

Midplane.jpg Onyx2 Deskside Circled in red

  • Also known as System Identification Number in techpub guides.
  • Can not transfer a NIC from an Octane into a Fuel.
  • In SGI Terms a NIC is a 'Number In Can'. Its looks like a battery but it contains the systemid. The Origin2000 have the same and you can see it when you remove the MSC.


  • Fuel and Router bricks in Origin 3(x)00 series use a Dallas Semiconductor DS1742W-120.




Integrated Circuit in SGI Origin 300 NUMALink bricks, SGI Origin 3000 router bricks and SGI Fuel. The system serial number is stored in this chip. Effectively a Number In a Can.

Fuel id chips.jpg

In a SGI Fuel a Dallas 1742W-120 is used in conjunction with an Atmel chip to form the system ID.

See Also

See Also