Glossary
========

.. glossary::

  APU
    Accelerated Processing Unit.  CPU and GPU are combined on a single chip.

  Cassini
    The HPE 200G Slingshot NIC.

  CORAL
    Collaboration of Oak Ridge, Argonne, and Livermore.  The first CORAL
    procurement was awarded to IBM and brought the Power-9 based pre-exascale
    systems *Sierra* to Livermore and *Summit* to Oak Ridge in 2018.

  CORAL-2
    The second CORAL procurement was awarded to HPE and brought the Cray EX
    based exascale systems *Frontier* to Oak Ridge in 2022, *Aurora* to
    Argonne in 2023, and *El Capitan* to Livermore in 2024.

  CRD
    Kubernetes Custom Resource Definition.  A mechanism for extending the
    Kubernetes API with application-specific resource types.  DWS and NNF
    make heavy use of CRDs to represent storage allocations, file system
    state, mount points, and data movement operations.

  CXI
    Cray eXascale Interface.  Another way of referring to the Cassini NIC.

  CXI Service
    An authorization token that grants specific UNIX user and group IDs
    access to a set of Cassini NIC resources: :term:`VNI` numbers,
    :term:`traffic classes <traffic class>`, and NIC hardware entities such
    as transmit and receive queues.

    .. figure:: images/dragonfly.png
      :alt: Dragonfly topology
      :align: right
      :scale: 70 %

      a simplified dragonfly network

  DWS
    Data Workflow Services.  An HPE software stack, running as a set of
    Kubernetes controllers, that manages the lifecycle of :term:`Rabbit`
    storage allocations on behalf of a workload manager.

  dragonfly
    A two-level interconnect topology that divides switches into groups.
    The switches in each group have some node ports, inter-group ports,
    and intra-group ports.  The intra-group switch ports fully connect
    the switches in the group (level 0), although other topologies are
    permitted.  The inter-group switch ports fully connect the groups
    (level 1).

  finalizer
    A Kubernetes mechanism that prevents an object from being deleted until
    specific cleanup actions are complete.  An object with a finalizer set
    will not be removed from the API server even after a delete request until
    the finalizer is explicitly removed by a controller.

  fabric manager
    The fabric manager configures, manages, and monitors the :term:`Slingshot`
    network.  It runs on one dedicated server and on the :term:`Rosetta`
    switches.

  MPICH
    The Argonne MPI implementation.  Cray MPICH is a proprietary fork of MPICH.

  PALS
    Parallel Application Launch Service.  The Cray PALS library provides
    placement, interconnect, and debugger information to applications.

  PMI
    Process Management Interface, a quasi-standard bootstrap API and protocol
    for MPI implementations.

  NNF
    Near-Node Flash.  The HPE near-node-local flash storage product that
    interfaces with nearby Cray EX compute nodes via PCI Express.  The
    :term:`Rabbit` is the NNF node.

  Rabbit
    HPE near-node-local storage product that interfaces with nearby Cray EX
    compute nodes via PCI Express.

  RDMA
    Remote Direct Memory Access.  A low-latency technique that allows a NIC
    to directly access application memory.

  Rosetta
    The HPE 200G, 64-port Slingshot switch.

  traffic class
    A :term:`Cassini` NIC quality of service level.  The classes include
    best effort, bulk data, low latency, and dedicated access.

  Slingshot
    The HPE 200G Ethernet-compliant interconnect.  :term:`CORAL-2` is based
    on Slingshot-11 with :term:`Cassini` NIC and and :term:`Rosetta`
    switch devices configured in a :term:`dragonfly` topology.

  VNI
    Virtual Network Identifier.  An integer packet label used to isolate
    :term:`Slingshot` RDMA traffic.