1 Cray Supercomputers: The Cray X1 Sara Prochnow Kevin Boucher Brian Femiano Allen Peppler

2 Introduction Fun Fact- Cray supercomputers consisted of the first vector register technology, immersion cooling technology, gallium arsenide semiconductor technology, and RISC architecture The X1 is the latest supercomputer from Cray Inc. The material presented today is that which relates closest to the material covered in Abzug’s CS350 class.

3 Nodes The basic unit of the Cray machine A node is made up of four multi-chip modules (MCM) and main memory The MCMs and memory are attached to routers that allow communication between different nodes

4 Multi-Chip Modules (MCM) Each MCM contains a single multi-streaming processor (MSP) MSPs are made up of four scalar single- streaming processors (SSP) and two megabytes of ecache

5 Single-Streaming Processors (SSP) The four SSPs that make up the MSP are scalar processors with two vector registers which allow the SSPs to fetch, decode, and execute two instructions per clock cycle Each of the scalar processors contains an instruction and data cache A data and instruction cache address is forty-eight bits long. The tag field is thirty-five bits long, the set field is eight bits long, and the line-offset field is five bits long

6 ECache The ecache is a high speed cache that gives the processors a large amount of temporary storage The ecache is similar in structure to the data and instruction caches –It is addressed exactly the same, but its format is slightly different. Instead of 256 sets of lines, it has 32,768 sets of lines.

7 Memory Sixteen memory controller chips and thirty-two dynamic random access (DRAM) daughter memory cards are in each node The daughter memory cards come in two sizes, 288 megabit chips and 576 megabit chips. There is a total of sixteen gigabytes or thirty-two gigabytes of memory available

8 Global Addressability every node is connected by means of a system of routers, which allows the memory on each node to be globally addressable memory on any node can be accessed by not only the components on its node, but by any component on any node

9 Word Size The memory on each node is broken up into seventy- two bit words –Sixty-four of these bits are used for data and can be used for sixty-four bits operations or broken up into two sections for thirty-two operations –The other eight bits are used for single-error- correction, double-error-detection

10 Modes Memory can run in two possible modes that will allow for the loss of memory cells due to unforeseen circumstances –The first mode reserves half of the memory chips on each card to cover the potential loss of a memory chip. –The second mode reserves half of the daughter cards in case an entire card is lost.

11 Cabinets Cray machines can be purchased in one of two types of cabinets, air cooled and liquid cooled –An air cooled system can hold up to four nodes (sixteen MSPs) –A liquid cooled cabinet can hold up to sixteen nodes (sixty-four MSPs). How do these cabinets work?

12 Applications The Army High Performance Computing Research Center Nuclear simulation research Code breaking and cryptology

13 Still want to learn more? A small amount was presented today More can be found at: QUESTIONS?