IP27 is SGI's software architecture name for the system marketed under the names Origin 200, Origin 2000 and Onyx 2. IP27 is a ccNUMA architecture. The Origin 300, Origin 3000, Octane systems are architecturally similar.
IP27 systems are equipped with R10000 processors at clock rates from 180Mhz and R12000 processors at 250MHz. As a rare feature different processors and versions are permitted to be used mixed in a system which makes assembling a system from components or field maintenance drastically easier. The sole restriction is that both processors on a node board have to use the same clock speed.
IP27 systems come with an IOC3 network card on the mainboard; additional IOC3 cards may be present in the system in form of MENET XIO cards or IOC3 PCI cards. Linux supports the IOC3 but performance is rather moderate to say the least.
By standard IP27 systems are equipped with two Qlogic ISP1020 SCSI hostadapter per module. Origin 200 systems have space for 6 3.5″ internal drives on the primary SCSI bus and 2 internal 5.25″ half height or 1 full height device on the second.
IP27 is supported by Linux 2.4 and Linux 2.6. Due to vastly superior properties of Linux 2.6 on such large systems Linux 2.6 is urgently recommended for IP27 systems. Due to the size of typical systems and properties of the IP27 architecture only 64-bit kernels make sense and are supported. Linux 2.6 requires a small patch in addition to the CVS kernel. The patch is available from ftp://ftp.linux-mips.org/pub/linux/mips/people/ralf/ip27/.
In early 2001 an Origin 2000 became one of the first 32 processor systems to run Linux. A little later Linux did boot on an 128 processor Origin 2000. It took like two month until a Alpha-based Wildfire system did beat that record with it's 128GB of RAM. But the record of 128 processors did stay for over two years. Here some bootup messages.
Hardware documentation and patents
While hardware documentation still is not public a number of patents has been filed on technology used by Origins and its descendents - and for once these patents are actually readable. There are 5,915.104 and 6,604,161for the BRIDGE ASIC and 6,282,195 for the XBOW ASIC.