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Green (Origin 3800)

The SGI Origin 3800 machine has been named Green in honour of the English mathematician and miller George Green (1793-1841).


The system has 512 MIPS processors, each clocked at 400 MHz and each capable of a peak performance of 800 Megaflops. The machine uses SGI's NUMAlink interconnect to provide very low latency, high bandwidth communication between the processors and the 512 Gigabytes of globally shared memory. The system has some local disk for temporary storage as well as access to the storage area network (SAN). 504 processors and 504 Gigabytes of memory are available to applications, and this resource can all be used for a single job. Note that Green is a batch only system and all jobs must be submitted from Wren, the Origin 300 machine. Image of Green



Aspect of the system Details
Processors 512 x 400 MHz MIPS R12000 processors
Memory 512 GBytes memory
Cache hierarchy Each processor has 8MB Level 2 cache, 32 KB Level 1 data cache, 32 KB Level 1 instruction cache
Interconnect SGI NUMAlink providing sub-microsecond hardware latency, 3-5 microseconds MPI latency, sub-microsecond latency for one-sided communications, 6.4GB/s aggregate bandwidth per brick (4 CPUs).
Operating System IRIX
Partitioning This machine is a 512 processor single system image (SSI)
Maximum job size 504 processors can be used for a single run
Theoretical peak performance 400 Gigaflops - 512 processors x theoretical peak of 800 Megaflops
Host Address

Configuration Information

Green is configured with 4 processors set aside for operating system tasks, 4 processors for interactive access for system administrators and other monitoring tasks by the application support team, and the remaining 504 processors available for batch work. There is no facility for direct interactive access to this machine.

Green is visible to the outside world as and therefore it is possible to make use of applications which use the X windowing system provided that the DISPLAY environment variable is set to the appropriate value in your batch submission script and you have allowed access to your local machine (i.e. your local firewall allows incoming X traffic and you have used the xhost command to give access permissions to green).

Page maintained by This page last updated: Monday, 23-Aug-2004 11:38:55 BST