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Commonly used phrases and terms

Term Explanation
2-factor authentication Authentication method using 2 factors for login. The first factor is often a password. The second factor is often a generated token/code.
Batch job A user create script the defines what tasks should be performed. The script is submitted to a job scheduler to be executed on the cluster nodes.
Centre storage Shared file system available on all nodes. LUNARC currently uses an IBM SpectrumScale Parallel file system as center storage resource.
Compiler Compiles source code for languages such as C, C++ and Fortran to executables/machinecode that can be run directly by the processor.
Core Individual processing element, 20-48 per node. Can also be called a CPU.
CPU Central Processing Unit. A processor often contain several CPUs (cores).
CPU-time Refers to the sum of all execution times for all tasks in a parallel job.
Disk snapshot The center storage at LUNARC stores snapshots in time of the entire file structure. This can be used to retrieve files that have been mistakenly been erased.
GPU This denotes a NVIDIA/AMD co-processor. Can be used for both computing as well as graphics.
Hardware accelerated graphics Graphics rendering that using hardware accelerator GPU for drawing in 2D and 3D.
HPC High Performace Computing
Job script See batch job
Local disk Local disk storage for each node. This storage is not shared between the nodes.
LUNARC Lund University NIC Application Research Center
LUNARC HPC Desktop Remote desktop solution provided by LUNARC.
Module A single software package in the module system. Usually denoted by a name/version pair. MYAPP/1.1.
Module system System for organising software installs. Enables multiple version of software to be installed on the same system. LUNARC uses the module system Lmod.
MPI Message Passing Interface - An application programming interface (API) for programming multinode parallel applications. OpenMP/Intel MPI are commonly available implementations of this API
Node A physical computer/server in a compute cluster.
OpenGL Open standard for hardware accelerated graphics.
OpenMP Open Multi-Processing - An application programming interface (API) for shared-memory multi-processing withing a single server/node.
OTP One Time Password
OTP-token Special code generated by the authenticator application Pocket Pass.
Parallel job A job that consists of multiple tasks running on a single or multiple nodes.
Partition Several nodes/servers grouped together in a compute cluster. Usually nodes in a partition share the same properties, such as processor, memory or accelerators.
Processor This denotes a multi-core processor, housing many processing elements/CPU/cores.
PuTTY Graphical SSH client available for Windows.
Queue When submitting a job it will end up in a queue in the schedulerm, waiting for resources to become available.
Quota Amount of disk space allocated for a user. Quotas also limit the number of files a user can create. When applying for a storage project in SUPR, users request both disk space and how many files they will use.
SLURM Simple Linux Utility for Resource Management
Socket This is the “plug” the processor gets plugged into. Used as a synonym for the processor. Usually 2 per node.
SSH Secure Shell - Secure protocol used when connecting to the LUNARC resources. SSH clients are available for Linux, Windows and macOS X.
SUPR SNIC User and Project Repository - Web service for creating project proposals for available resources both at LU and nationally.
SUPR Project Refers to an approved project proposal.
SUPR Proposal Refers to a project proposal not yet submitted for approval in SUPR.
Task This is a software concept. It denotes a process, which is an instance of a running program. It has its own data and instruction stream(s). It can fork multiple threads to increase the computational speed. Serial programs and pure MPI programs do not spawn threads.
Thread This is a software concept. A thread is a stream of instructions executed on the hardware. It is part of a task and shares resources such as data with other threads within the same task.
Toolchain Refers to a specific compiler version with associated libraries for MPI.
Walltime Refers to the real-world (wristwatch, wall-clock) time during which a paralell job executes.

Author: Jonas Lindemann (LUNARC)

Last Updated: 2022-10-06