Glossary¶

The following glossary of terms addresses an Islandora context. When comparing new Islandora and Fedora to older versions it may also be helpful to reference the Islandora 7 Glossary.

Alpaca¶

Islandora's event-driven middleware based on Apache Camel that handles communication between various components of Islandora, for instance synchronizing Drupal data with a Fedora repository and the Blazegraph triple store.

Ansible¶

Open source software for provisioning, configuration management and application deployment. In the context of Islandora, Ansible can be used to install and maintain the Islandora software stack more conveniently and efficiently on a server or group of servers. The configuration and installation instructions are captured in a human-readable list of tasks, called 'Playbook'. The Islandora Playbook for Ansible is one of the installation methods currently supported by the Islandora community.

Apache¶

Refers to the Apache Software Foundation, a not-for-profit organization supporting various open source software development projects. The Islandora software stack consists of different components that are developed under the umbrella of the Apache Software Foundation, for instance Apache ActiveMQ, Apache Camel, the Apache HTTP server (webserver), Apache Karaf, Apache Solr, and Apache Tomcat.

Can in a narrower sense refer to the Apache HTTP server.

API¶

See Application Programming Interface

Application Programming Interface¶

Also API; a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software.

Blazegraph¶

Blazegraph is an open source triplestore and graph database. Islandora ships Blazegraph as part of the software stack. Metadata about Resource nodes is synchronized between the Drupal database and Blazegraph. Data in the Blazegraph triple store can be queried using SPARQL.

Bundle¶

A bundle is the generic name for a sub-type of a Content Entity type in Drupal. To illustrate: Node and Taxonomy Term are both names of Content Entity types, and both have sub-types ("bundles"). The bundles of Node are called "Content Types" and the bundles of Taxonomy Term are called "Vocabularies". Each bundle includes its own configurations of what fields are present on the bundle and how they are entered and displayed. A bundle is thus part of the configuration of your site. Some fieldable Content Entity Types, such as User, do not have bundles.

Cantaloupe¶

Cantaloupe is an image server written in Java. It implements the IIIF Image API, which means it handles deep zooming of large images and other image manipulations. It is required to serve images to some viewers such as Mirador and OpenSeadragon.

Checksum¶

Checksums are a sequence of numbers and letters to check data for errors. If you know the checksum of an original file, you can use a checksum utility to confirm your copy is identical. Checksums can be used to check the Fixity of a file.

CLAW¶

CLAW (CLAW Linked Asset WebDataFrameWork) was the development code name for the software released in June 2019 as Islandora 8, now called Islandora.

Collection¶

A collection is a way of grouping related resources together, much like a directory on a computer. Collections can contain any number of related resource Nodes and sub-collections.

Configuration¶

Configuration entity¶

Content¶

Content entity¶

Content model¶

Deprecated concept used in Islandora Legacy; see Islandora Model.

Content type¶

A type of Node. Content types are the "bundles" of Nodes, which are a type of Content Entity in Drupal. A content type importantly defines a set of fields and how they are displayed. While a content type describes a type of content entity, the information that makes up the content type itself is all part of your site's configuration.

The standard Drupal Content types are 'Article' and 'Basic page'. Islandora Starter Site adds 'Repository Item' as a Content type, defining metadata fields typically used to describe digital resources. You can easily create your own content types.

Context¶

An "if-this-then-that" configuration created using the Drupal Context contrib module. Islandora extends the capabilities of Context by adding custom Conditions, custom Reactions, and by evaluating context at specific times to allow Contexts to be used for derivatives, indexing, and display.

Crayfish¶

A collection of Islandora microservices. Some microservices are built specifically for use with a Fedora repository, while others are just for general use within Islandora.

Datastream¶

Deprecated terminology, refers to how Fedora 3/Islandora Legacy stored files as part of a resource ('object') in the Fedora repository. Replaced by Drupal Media entities, which 'wraps' Files in an intermediate structure. This allows Fields to be attached to files, for instance for storing technical metadata.

Derivative¶

A version of a file which is derived from an uploaded file. For example, a thumbnail generated from an uploaded image. Islandora uses microservices to generate derivatives. See the concept page for Derivatives.

Docker¶

Docker is a platform that use OS-level virtualization to deliver software in packages called containers. Islandora uses Docker as part of ISLE, a suite of Docker containers that run the various components of Islandora.

Drupal¶

Drupal is an open source web content management system (CMS) written in PHP. Known for being extremely flexible and extensible, Drupal is supported by a community of over 630,000 users and developers. Drupal sites can be customized and themed in a wide variety of ways. Drupal sites must include Drupal Core and usually involve additional, Contributed code.

Drupal Core¶

The files, themes, profile, and modules included with the standard project software download.

Drupal Roles¶

Roles are a way of assigning specific permissions to a group of users. Any user assigned to a role will have the same permissions as all other users assigned to that role. This allows you to control which users have permission to view, edit, or delete content in Drupal. Islandora provides a special role called fedoraAdmin that is required to have actions in Drupal reflected in Fedora.

Entity¶

A Drupal term for an item of either content or configuration data. Examples include Nodes (content items), Blocks, Taxonomy terms, and definitions of content types; the first three are content entities, and the last is a configuration entity. In common usage, the term often refers to Drupal content entities like Nodes or Taxonomy terms.

Fedora (Repository Software)¶

Fedora is a digital asset management architecture upon which institutional repositories, digital archives, and digital library systems might be built. Fedora is the underlying architecture for a digital repository, and is not a complete management, indexing, discovery, and delivery application.

The Fedora repository functions as the standard smart storage for Islandora.

FFmpeg¶

FFmpeg is a cross-platform audio and video processing software. In Islandora, FFmpeg is provided by the Crayfish microservice, Homarus.

Field¶

Data of a certain type that is attached to a content entity. A field is made up of field storage which inclues some low-level configuration that is shared across all field instances, and a field instance, which configures how that field appears on a bundle. Fields also have field widgets that govern data entry, and field formatters which control how the field is displayed to site visitors.

Field instance¶

A field, configured to show up on a bundle. It is possible to reuse fields on different bundles, and they share the same field storage but are different field instances and can have different configurations (such as field name, description, cardinality, required, etc).

For example, the Repository Item Content type has a field instance for Alternative Title, with the following configuration:

Display name: Alternative Title
Help text: (blank)
Required: no
Translatable: yes
Field visibility and permissions: not set
Default value: none

Field formatter¶

A field formatter configures how a field instance is displayed to site visitors. The formatters available depend on the field type. For example, an EDTF-type field can use the "Default EDTF Formatter", which can be configured (per field instance) to be big- or little-endian, and to show year, month, and day info in a variety of ways. Field Formatters are configured on the "Manage Display" tab of a bundle.

Field type¶

The type of a field instance or field_storage. Drupal Core defines several field types and modules can define additional field types. The field type determines what widgets and field formatters are available, as well as what configuration options are available in the field instance. Some commonly used field types in Islandora include:

Text (plain, long)
- Allows long text values
- Displays the input text
Text (formatted, long)
- Allows long text values
- If a format like “full_html” is set on the field,
  will be displayed as a paragraph break rather than
Entity reference
- Populated by a link to another Drupal/Islandora entity
- Configurable behaviors include: what kind of entity can be linked to, how the data entry interface words (drop down menu or autocomplete), general patterns of how these references get displayed (show the referenced thing, show a link to the referenced thing, show unlinked name of the referenced thing).
Typed relation
- An extended variation on Entity reference field type
- List of available relationship types (labeled “Available Relations”) can be configured per field instance. A code and a display value are recorded for each type (for example: relators:aut|Author). ‘relators’ acts as a linked data namespace. ‘aut’ is the code that, combined with the base namespace URI configured elsewhere, will create the linked data expression of what is recorded in this field ( this node hasAuthor taxonomyTermID )
EDTF
- Holds a string formatted according to the EDTF standard
- What kinds of EDTF features are allowed can be configured in the widget and how the date is presented to site visitors can be configured in the field formatter

Field Storage¶

Low-level configuration that determines how the field data is stored in the database. This often includes the maximum length of the data, and whether the field is single-valued or repeatable (though that can often be overridden at the field instance level). Compare: field instance

FITS¶

File Information Tool Set, a set of software components for identifying, validating and extracting of technical metadata for a wide range of file formats.

Fixity¶

Also file fixity; digital preservation term meaning that a digital file remains unchanged ('fixed') over time. Fixity checking verifies that a file has not been corrupted or manipulated during a transfer process or while being stored. Typically, a fixity checking process computes checksums or cryptographic hashes for a file and compares the result to a reference value stored earlier. The Riprap microservice and the contributed Riprap Islandora module support fixity checking and error reporting in Islandora.

Flysystem¶

Flysystem is a filesystem abstraction library for PHP. Islandora uses Flysystem to swap about different backend filesystem applications. Islandora provides a custom Flysystem adapter for Fedora.

GLAM¶

Acronym for "galleries, libraries, archives, and museums".

GUI¶

Acronym for "Graphical User Interface". Often refers to taking actions through Drupal's administrative interface in a web browser as opposed to effecting the same changes through Drush or programmatically.

Greenfield¶

An installation without legacy constraints. Usually refers to a brand new system where users load new content, as opposed to migrating content from a previous system.

Imagemagick¶

Imagemagick is an open-source image processing library. In Islandora, Imagemagick is provided by the Crayfish Microservice, Houdini.

hOCR¶

hOCR is an open standard for representing OCR (Optical Character Recognition) results, including text positioning, as HTML. hOCR can be produced by Tesseract, and can be displayed as an overlay on an image by Mirador.

Homarus¶

Homarus is a microservice wrapper for FFMpeg. It is part of Crayfish.

Houdini¶

Houdini is a microservice wrapper for Imagemagick. It is part of Crayfish.

Hypercube¶

Hypercube is a microservice wrapper for Tesseract. It is part of Crayfish.

IIIF¶

The International Image Interoperability Framework. Generally pronounced "triple-eye-eff." A set of open standards and APIs that help archives, libraries, and museums make the most of their digitized collections with deep zoom, annotation capabilities, and more, and also the community of users and developers that support the framework.

IIIF Manifest¶

Defined in the IIIF Presentation API, it is a document that includes "The overall description of the structure and properties of the digital representation of an object." In Islandora, it lists one or more files, in order, that can be displayed in a viewer such as Mirador or OpenSeadragon.

Ingest¶

To ingest an object is to add an entry for it in Islandora. This can be done through the Drupal graphical user interface or one of the Drupal APIs (REST, Migrate API). The third-party contributed software Islandora Workbench uses the Drupal REST API for convenient bulk ingest.

In the context of digital repositories, ingest refers to the process by which the repository software imports and subsequently processes an object, creating derivatives automatically, and running any other processing that is configured to occur when an object is added. This would be distinguished by software which simply stores objects after import (with or without associated files) and performs no processing. The Islandora GUI and the documentation sometimes use other terms such as 'import' or 'add resource node'. In such contexts, these terms generally refer to the ingest process.

Islandora 8 (8.x, 2.0)¶

Islandora 8, 8.x, 2.0, and CLAW are all deprecated names for the current version of Islandora. They referred to Islandora's use of Drupal 8, and being a major shift away from Islandora Legacy (formerly known as Islandora 7 or 7.x as it runs on Drupal 7).

Islandora Install Profile¶

The Islandora Install Profile (in GitHub as Islandora Install Profile Demo, is a Drupal install profile that was developed by Born Digital, an Islandora vendor. It defines an Islandora with additional modules, themes, and configurations that were not defined in the Islandora Starter Site (formerly Islandora Defaults). The Install Profile and the Starter Site share the same function (though they approach it differently) and it is not possible to use both.

Islandora Starter Site¶

The Islandora Starter Site is a way to install Drupal that provides a functional Islandora "out of the box." It was created from Islandora Defaults [now defunct] by discoverygarden inc, an Islandora vendor. The Islandora Install Profile and the Starter Site share the same function (though they approach it differently) and it is not possible to use both.

Islandora model¶

"Islandora Models" is a taxonomy vocabulary that comes by default with Islandora. As of 2024-08-12, it includes the following terms:

Audio
Binary
Collection
Compound Object
Digital Document
Image
Newspaper
Page
Paged Content
Publication Issue
Video

The Repository Item Content type (part of the Islandora Starter Site) has a “Model” field instance which is an Entity reference field configured to be populated by references to terms in this vocabulary. The “Model” field is one of only two required fields on the Repository Item in the default settings.

Contexts and other system code (such as themes) may use this field to control the display and behavior of different Repository Item types.

Islandora playbook¶

A set of human-readable YAML files, containing instructions for automatically configuring a server environment and installing the different components of the Islandora software stack. The instructions recorded in Playbook are executed by Ansible. The Islandora Playbook for Ansible is one of the installation methods currently supported by the Islandora community.

ISLE¶

ISLE, or ISLandora Enterprise, is a community initiative to ease the installation and maintenance of Islandora by using Docker. ISLE is one of the installation methods currently supported by the Islandora community.

JSON-LD¶

JSON-LD (JavaScript Object Notation for Linked Data) is a method of encoding linked data using JSON.

Linked data¶

In computing, linked data is structured data which is interlinked with other data so it becomes more useful through semantic queries. Linked data typically employs the Resource Description Framework for data modelling.

Manifest¶

See IIIF Manifest.

Matomo¶

Matomo, formerly called Piwik, is a software for tracking visits to websites. It is an open source alternative to Google Analytics and allows the generation of website usage reports.

Media¶

Media are a Drupal Content entity type, which allows to manage Media items (Files) like images, documents, slideshows, YouTube videos, tweets, Instagram photos, etc. The Media module provides a unified User Interface where editors and administrators can upload, manage, and reuse files and multimedia assets. In the context of Islandora, Media entities 'wrap' files and provide a place to store file-specific metadata.

See https://www.drupal.org/docs/8/core/modules/media/overview for more information on the Drupal foundations, and refer to https://islandora.github.io/documentation/user-documentation/media/ for how Islandora uses Media.

Memento¶

Protocol specification that allows a web client to request an earlier/historic state web resource (if available). Fedora implements the Memento protocol to store and serve versions of content in a Fedora repository.

Mirador¶

Mirador is a javascript-based zoomable image Viewer. It is related to (and more fully-featured than) OpenSeadragon. It has the ability to do zooming, display multiple pages, and display positioned text (e.g. hOCR or attributions). To render an image through Mirador, it must be provided a IIIF Manifest and the images must be served through a IIIF-friendly image server such as Cantaloupe.

Microservice¶

A software development technique — a variant of the service-oriented architecture (SOA) structural style — that arranges an application as a collection of loosely coupled services. In a microservices' architecture, services are fine-grained and the protocols are lightweight.

Module¶

Software (usually PHP, JavaScript, and/or CSS) that extends site features and adds functionality. Drupal modules conform to a specific structure allowing them to integrate with the Drupal architecture.

Node¶

Usually refers to a piece of Drupal Content of the type 'Node'. This includes actual pages, articles, and Resource nodes. Nodes must belong to a specific node bundle, called a "Content Type".

OAI-PMH¶

The Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) is a protocol developed for harvesting metadata descriptions of records in an archive so that services can be built using (aggregated) metadata from many archives. Islandora allows to publish metadata in a way conformant to OAI-PMH, acting as a so-called OAI-PMH endpoint.

Ontology¶

In computer science and information science, an ontology encompasses a representation, formal naming and definition of the categories, properties and relations between concepts, data and entities. In the narrower context of the Resource Description Framework (RDF), an ontology is a formal, machine-readable description of the 'vocabulary' that can be used in a knowledge graph. An RDF ontology for instance specifies classes of things or concepts (e.g. the class of all book authors) and properties of classes/class instances (e.g. an author's name, birthdate, shoe size; also the fact that an author has written something that is in the class of books).

Open Source¶

Open source describes a method of software development that promotes access to the end product's source code. Islandora is an open source product with an active development community, operating under the GPL license (2.0) for Drupal components and the MIT license for non-Drupal components.

OpenSeadragon¶

OpenSeadragon is javascript-based zoomable image Viewer. It has the ability to do zooming and display multiple pages. To render an image through OpenSeadragon, it must be provided in a IIIF Manifest.

PR¶

See Pull request

Pull request¶

Also PR; sometimes also known as merge requests; technical term from distributed version control systems for software code like Git. Code contributors can request that the maintainer of a code repository 'pulls' the code change into the repository after approval.

RDF¶

See Resource Description Framework

Repository Item¶

A type of content entity that comes "out of the box" with the Islandora Starter Site. See also: Resource Node

Resource Description Framework¶

Also RDF; family of World Wide Web Consortium (W3C) specifications originally designed as a data model for metadata. It has come to be used as a general method for conceptual description or modeling of information that is implemented in web resources. The data is modelled as a set of statements, also known as triples. A collection of RDF statements intrinsically represents a directed graph. Data represented according to the RDF specifications can be serialized in different ways, for instance using JSON-LD.

Resource Node¶

A Resource node is a generic Islandora term for a Drupal Node that represents a single conceptual item or object stored in an Islandora repository. It acts as a stand-in for all files and metadata associated with that item, and is the place where the item 'lives' as a visitable URI.

The term 'Resource node' is specific to Islandora. Typically, Resource nodes in an Islandora installation will use a specific Content type for the digital assets stored in the repository.

For example, a video stored in Islandora will have a Resource node, with metadata stored in Fields. Attached to the Resource node is a Media entity, which encapsulates the preservation-grade file. The Resource node may be linked to further Media, for instance for a thumbnail, web-friendly derivative, and technical metadata associated with the resource node. The Resource node may also belong to one or more collections.

Source Field¶

A Drupal term for the main file-type field on a Media. The names of these fields differ across Media Types, such as "Image" (field_media_image) on Image media, and "Video File" (field_media_video_file) on Video media. While it is possible to add other fields, including file fields, to a Media, the source field is the one configured during the creation of a Media Type. Islandora provides utility functions to get the source field from a Media (MediaSourceService.php).

Taxonomy term¶

A Drupal Content Entity of the type 'taxonomy term'. Taxonomy terms belong to vocabularies which define what fields are available and how they behave. Drupal generally uses terms contained in taxonomies or vocabularies to classify content (tag or category). Taxonomy terms are used in Islandora to establish locally controlled vocabularies for describing resources, for instance for standardised spellings of names or subject terms.

Tesseract¶

Tesseract is an open-source OCR (Optical Character Recognition) software. It can perform OCR in multiple languages. It can produce OCR (plain text) and hOCR (HTML, which includes positional data). In Islandora, Tesseract is provided by the Crayfish Microservice, Hypercube.

Theme¶

Software and asset files (images, CSS, PHP code, and/or templates) that determine the style and layout of the site. The Drupal project distinguishes between core and contributed themes.

Vagrant¶

Vagrant is an open-source software product for building and maintaining portable virtual software development environments (virtual machines). The Islandora Playbook includes a 'vagrantfile', a set of instructions that allows users to create a local virtual machine environment which will subsequently run Ansible to execute the configuration and installation steps recorded in the Islandora Playbook.

VBO¶

See Views Bulk Operations.

View¶

Drupal Views let you query the database to generate lists of content, and format them as lists, tables, slideshows, maps, blocks, and many more. The Views UI module, part of Drupal Core, provides a powerful administrator interface for creating and editing views without any code. There is a large ecosystem of extension modules for Views.

Views power many of the Islandora features, including viewers, IIIF Manifests, and search.

View Mode¶

A View Mode is a way that a piece of Drupal content can be rendered. View modes let you create alternate configurations for what fields get displayed, in what order, and rendered in what field formatters. View modes are created under Manage > Display Modes > View Modes, but are configured at the bundle level (after first enabling that view mode to have its own configuration). If the requested view mode does not have a custom configuration, then the "Default" view mode will be used.

In Views, you can choose to show "Rendered entities" (usually as opposed to "Fields"). Here, you can select which view mode to use to render the results.

Viewer¶

A Viewer is any tool that allows Drupal to embed, display, or play back a particular object in a web-accessible format. Viewers are typically projects unto themselves. To use a viewer within Drupal usually involves a Library containing the viewer's code, as well as a Drupal Module that makes the viewer code appear within Drupal. Usually a viewer displays a single binary file, but some viewers (e.g. Mirador and OpenSeadragon) can display an entire manifest (ordered list of files).

Views Bulk Operations¶

Also called VBO; a Drupal Module for performing bulk/batch operations on Nodes selected by a View definition.

Virtual Machine Image¶

The Virtual Machine Image allows you to mount a fully working version of Islandora on your local machine as a separate virtual machine.

Vocabulary¶

A Drupal configuration entity that holds taxonomy terms. The vocabulary defines what fields are available on each term and how the terms behave. Vocabularies are the "bundles" of taxonomy terms.

Weight¶

Drupal field that stores an integer value on an entity, allowing to represent the relative order of the entity in relation to other entities of the same type or subtype. Used by Islandora to store the order of components in compound objects, for instance pages in paged content items (books, serials).

YAML¶

YAML is a human-readable data-serialization language. It is commonly used for configuration files and in applications where data is being stored or transmitted. Software applications like Drupal or Ansible store configuration information in YAML files for easy transportability of a configuration.

Some definitions adapted from Wikipedia and Drupal.org

Last update: September 25, 2024