Glossary

This section defines the main concepts and terms used throughout the LEXIS Platform documentation.

List of Abbreviations

Abbreviation	Meaning
AAI	Authentication and Authorisation Infrastructure.
API	Application Programming Interface.
DAG	Directed Acyclic Graph.
DDI	Distributed Data Infrastructure.
FAIR	Findable, Accessible, Interoperable, and Reusable principles.
GPU	Graphics Processing Unit.
HEAppE	High-End Application Execution Middleware.
HPC	High-Performance Computing.
iRODS	Integrated Rule-Oriented Data System.
LWD	LEXIS Platform Workflow Definition.
OIDC	OpenID Connect.
PI	Principal Investigator.
RBAC	Role-Based Access Control.

Main Platform Concepts

Term	Description
Apache Airflow	Workflow orchestration engine used to schedule and monitor LEXIS Platform tasks.
Application	Definition of a computational workload that can be executed by a workflow task.
DDI	LEXIS Platform subsystem responsible for datasets, metadata, storage, data transfer, and staging.
Expirio	Service for secure storage and lifecycle management of tokens and other credentials required by workflows.
HEAppE	Middleware used to submit and monitor jobs on integrated HPC systems and map execution requests to provider-side identities and accounting contexts.
HPC Command Application	HPC application represented by a predefined HEAppE command template.
HPC Container Application	Containerised application executed on an HPC system, typically using an Apptainer image.
iRODS Zone	Provider-operated iRODS environment used for managed storage of dataset files and associated metadata.
Keycloak	OIDC provider used for authentication and federation with external identity providers.
LEXIS Platform Dataset Listing	List of private, project, and public datasets accessible to a user through the LEXIS Platform data services.
LEXIS Platform Dataset	Logical collection of zero or more files, directories, and associated metadata managed through DDI.
LEXIS Platform Project	Main collaboration and authorisation context grouping users, datasets, workflows, applications, and access to assigned Resources.
LEXIS Platform Task	Individual computational or data-management operation within a LEXIS Platform Workflow.
LEXIS Platform Task Execution	Concrete execution of a task within a LEXIS Platform Workflow Execution.
LEXIS Platform Workflow	Directed graph of computational and data-management tasks, their configuration, dependencies, and data flow.
LEXIS Platform Workflow Catalogue	Repository of workflow templates available to users for creating and executing workflows.
LEXIS Platform Workflow Definition (LWD)	YAML-based declarative format used to describe a LEXIS Platform Workflow.
LEXIS Platform Workflow Execution	Concrete run of a workflow with specific inputs, parameters, Resources, task executions, and outputs.
LEXIS Platform Workflow Template	Reusable description of workflow tasks, their dependencies, inputs, outputs, and execution sequence.
Location	Physical or logical infrastructure endpoint where an allocation can be consumed, such as an HPC system, Kubernetes environment, or storage infrastructure.
OpenSearch	Central metadata index used by DDI for dataset discovery and search.
Principal Investigator	Person responsible for a provider-side HPC allocation and its appropriate use.
Project Membership	Association of a User with a LEXIS Platform Project, including the project role used for authorisation.
Provider	Organisation operating infrastructure connected to the LEXIS Platform, such as an HPC centre, Kubernetes site, or storage provider.
Resource	Abstract compute or storage allocation provided to a project, for example CPU node-hours, GPU-hours, or a storage quota.
Resource Assignment	Association between a Resource and a Location defining the concrete HPC system, Cloud infrastructure, or storage system on which the allocation can be consumed.
Role	Set of permissions defining which operations a User may perform within a LEXIS Platform Project.
Staging Worker	Provider-side component that performs data transfers between managed storage and computational filesystems.
User	Authenticated person interacting with LEXIS Platform services.
UserOrg	Backend service maintaining users, projects, memberships, roles, Providers, Resources, Resource Assignments, Locations, and the RBAC information used for authorisation.