[[Include(/WikiToC)]]

== Concepts
This is a brief overview of the main concepts and terms needed to follow [wiki:CosmosOverview/Workflow]

=== Resources
Everything that Experimenters can interact with is referred to as a [wiki:Resources Resource]

To run an experiment, you will configure the resources that you need.

This includes:
* Compute
  * capable of having disk images loaded and saved
  * users can log into them with ssh after provisioning
* Software Defined Radios
  * FPGA images loaded with UHD
  * Radio paramaters controlled with UHD or other API
* RF Frontends
  * api to control switches, filters, and gain
* Network switches
  * connectivity defined with API
* Optical Devices
  * space switch, roadms, and other devices controlled with optical config service
  

Note, some resources will fall into more than one of the above categories, such as a compute machine with integrated SDR, like the [wiki:Hardware/sdr/usrp2974 USRP 2974]

=== [wiki:Architecture/Domains Domains]
* Resources are grouped under Domains. Each domain won't interfere with any others, and they are reserved completely separately.
* The hardware in a domain may span several sites, or may be contained within a single site.

=== Sites
* Physical locations where hardware is installed. 
* A site consists of one or more nodes.

=== [wiki:Hardware/Nodes Nodes]
* Nodes refer to a set of radio, compute, and other resources meant to be used as a unit.
* The resources in a node will share infrastructure such as power, networking, or RF frontends.
* Therefore, the use of resources within a node must be coordinated to avoid interference.
* It is possible to use a subset of the resources within a node

=== [wiki:UserGuide/CreateRes Reservations]
* Reservations allow users to obtain exclusive use of resources for a define time period.
* Currently, to ensure repeatable results, resources are reserved at the domain level.
* TODO: Once the framework is in place, it will be possible to reserve a combination of nodes + frequency allocation, but for now the time slot guarantees exclusive use.

=== [wiki:UserGuide/ImageVersions Images]
* Compute resources have their state defined by what disk image is loaded
* Predefined base images are available, and described at [wiki:UserGuide/ImageVersions]
* [wiki:Tutorials] will either use a base image, or a specific customized image.
* The normal workflow is to load a base image, make the changes you need, and then save your own customized image to preserve your work.
* Details on how to work with images are at [wiki:UserGuide/OmfQuickStart OMF Quick Start]

=== Tutorials

* [wiki:Tutorials] are used as both instructional tools, as well as starting points for developing your own experiments.
* For example, following the [wiki:Tutorials/Wireless/basic_usage basic usage tutorial], you will be able to send and receive RF data with a SDR.