Technical Glossary

ACL:

Access Control Lists are used to control file access from unauthorized users.

Adaptive Supercomputing:

The newest generation of Cray supercomputers will combine standard microprocessors (scalar processing), vector processing, multithreading and hardware accelerators in one unified high-performance computing platform.

AMO:

Atomic Memory Operations provide asynchronous and distributed synchronisation mechanisms across very large distributed memory systems.

AMD:

Advanced Micro Device

AOI:

Quality and test Automated Optical Inspection.

ASIC:

Application Specific Integrated Circuit

AXI:

Quality and test Automated X-ray Inspection

Back to Top

BMM:

Bit Matrix Multiply

Back to Top

CAF:

Co-array Fortran is a small extension to Fortran 95. It is a simple, explicit notation for data decomposition, such as that often used in message-passing models, expressed in a natural Fortran-like syntax.

CSA:

Comprehensive System Accounting provides a full accounting system that can collect and report data on the use of system resources.

Back to Top

DIMM:

Dual Inline Memory Module

DMA:

Direct Memory Access

Back to Top

ECC:

Error Correction Code

ECO:

Engineering Change Order. The ECO is controlled via the Cray Product Data Management system.

Back to Top

FC:

Fiber Channel

FIT:

Failures In Time rate is a statistic for a component that measures how many failures the component will have per one billion operating hours. The lower the FIT rate for a component is, the better the component is. Standard created by the Bell Communications Research Lab (Bellcore Standard).

FPGA:

Field Programmable Gate Array is a type of gate array that is programmed in the field rather than in a semiconductor fab.

FUG:

Functional Units Group

Back to Top

GB:

GigaByte (1024 MB, or 1024 x 1024 x 1024 Bytes)

GFlop:

109 Floating-point operations per second

GUI:

Graphical User Interface

Back to Top

HBA:

Host Bus Adaptor. It is the part in an external network that constitutes the interface between the network itself and the PCI bus of the node. In the context of this proposal, it is the Fiber Channel interface between the I/O nodes and the RAID controllers.

HEU:

Heat Exchanger Unit. An HEU is required in liquid cooled systems to exchange heat between air (used to cool the supercomputer) and the cooling liquid.

HT:

HyperTransport

HyperTransport:

A high-speed interconnection between integrated circuits, defining a protocol and electrical interface between the CPU, memory and peripheral devices.

Back to Top

ICMP:

Internet Control Message Protocol

ICT:

Quality and test In-Circuit Test

IP:

Internet protocol

Back to Top

KB:

KiloByte (1024 Bytes)

Back to Top

LTO-3:

Tape drive type

Lustre:

Global high performance parallel file system. Lustre file systems are accessed from any node in a system (compute or service) with the same level of performance.

Back to Top

MAID:

Massive Array of Idle Disks is a storage system comprising an array of disk drives that are powered down individually or in groups when not required. MAID storage systems reduce the power consumed by a storage array: Most of the drives in a MAID array are idle most of the time, but can be revived up and read faster than searching sequentially through magnetic tape.

MB:

MegaByte (1024 KB, or 1024 x 1024 Bytes)

MDS:

Lustre MetaData Server. File system metadata is information about the files and directories that make up a file system. This information can simply be information about local files, directories, and associated status information, but can also be information about mount points for other file systems within the current file system, information about symbolic links, and so on.

MFlop:

106 Floating-point operations per second

MIMD:

Multiple Instruction Multiple Data

MPP:

Massively Parallel Processing

MTBF:

Mean Time Between Failure

MTTR:

Mean Time To Repair

Back to Top

NAL:

Lustre Network Abstraction Level. NAL provides out-of-the-box support for multiple types of networks.

NAS:

Network-attached storage is hard disk storage that is set up with its own network address rather than being attached to computer. The network-attached storage device is attached to a local area network and assigned an IP address. File requests are mapped by the supercomputer to the NAS file server.

NIC:

Network Interface Card

Back to Top

OS:

Operating System

OSS:

Lustre Object Storage Server. The OSS is the hardware entity consisting of a processor node, and associated interface cards to the actual storage. Lustre scalability is achieved by configuring as many OSS’s as required to meet the desired bandwidth. It is important to note, that the OSS’s operate in parallel, independent from each other.

OST:

Lustre Object Storage Target. The OST is the software entity that handles block allocation, enforces security for client access, and performs parallel I/O operations to transfer file data. One or more OSTs run on an OSS. Object Storage Targets handle all of the interaction between client data requests and the underlying physical storage. On a Cray MPP system, several OSTs are configured per fiber channel.

Back to Top

PB:

PetaByte (1024 TB, or 1024 x 1024 x 1024 x 1024 x 1024 Bytes)

PBS Pro:v

Altair Batch management system

PE:

Processing Element

PFlop:

1015 Floating-point operations per second

Back to Top

RAM:

Random Access Memory

RISC:

Reduced Instruction Set Computer

RTT:

Remote Translation Table

Back to Top

SATA:

A standard for connecting hard drives into computer systems, based on serial signaling technology.

SLA:

Service Level Agreement.

SMP node:

Multi-processor node where each processor can access the entire node’s memory.

Socket:

A receptacle in the motherboard for a multi-core processor.

SRI:

System Request Interface in the AMD dual core Opteron processors.

SSI:

Serial Line Interface

Back to Top

TB:

TeraByte (1024 GB, or 1024 x 1024 x 1024 x 1024 Bytes)

TFlop:

1012 Floating-point operations per second

TLB:

Translation Look-aside Buffer is a table that contains cross-references between the virtual and real addresses of recently referenced pages of memory.

Torus:

3D mesh network where each end of a dimension is connected to the other end of the same dimension.

Back to Top

UDP:

User Datagram protocol

UPC:

Unified Parallel C is an extension to C99 providing a simple shared memory model for parallel programming and allowing data to be shared or distributed among a number of communicating processors. Constructs are provided in the language to permit simple declaration of shared data, distribute shared data across threads, and synchronize access to shared data across threads.

Back to Top

VRM:

Voltage Regulator Module. On each blade there are several voltage regulators. The Cray Hood uses redundant VRM to enhance the reliability of the system.

VTL:

Virtual Tape Library is a storage system that includes a disk, and software to emulate tape or a tape library.

Back to Top