| Overview | Histories | Table of Contents |
The OrganSpec standard allows you to represent, in one specification, the entire history of an instrument, with changes, removals and other modifications that were made over the years. When a program converts an XML OrganSpec to human-readable form, it can easily produce any of the following:
There are two mechanisms for providing historical information. One mechanism consists of the history fields that may appear in most elements; these are discussed in more detail below. The other mechanism is the History element, which should only be used for historical information that can't be represented using the history fields.
Many elements contain the fields "installedBy", "dateInstalled", "removedBy", and "dateRemoved". The fields allow you to represent when an element was added or removed from an instrument, and by whom. A few elements only contain "installedBy" and "dateInstalled", because removal doesn't make sense for those elements.
If an element's history fields are missing, that implies that the element's history is the same as its parent element. Thus, if an entire division was added or removed, it is not necessary to duplicate the history fields in all the stops for the division; only the Division element itself needs history fields.
The following table shows the history fields that are supported by the various elements:
| Element | Fields | Explanation |
| Accessory | all four | |
| Blower | all four | |
| Borrowed | none | inherits is historical information from its parent Stop element |
| Builder | none | |
| Case | all four | |
| CatalogID | none | does not represent a component of the instrument |
| Chamber | all four | |
| Composition | install only | compositions are not "removed", they are replaced by new compositions (or the stop is removed) |
| Console | all four | |
| Coupler | all four | |
| Division | all four | |
| History | special | the History element has its own date fields which are different from the other elements |
| KeyAction | install only | key actions are not "removed", they are replaced by new key actions |
| Keyboard | all four | |
| Location | all four | here it is not the Location which is installed or removed, but rather the organ is installed in or removed from the Location |
| MixtureRank | none | inherits is historical information from its parent Composition element |
| Organ | none | the Location element is used to represent the installation and removal of the entire instrument |
| Pressure | install only | wind pressures are not "removed", they are replaced by new wind pressures |
| Rank | all four | |
| Recording | none | does not represent a component of the instrument |
| Relay | all four | |
| Remark | none | does not represent a component of the instrument |
| Revision | none | does not represent a component of the instrument |
| Scale | none | inherits is historical information from its parent Stop or Rank element |
| Source | none | does not represent a component of the instrument |
| Stop | all four | |
| StopAction | install only | stop actions are not "removed", they are replaced by new stop actions |
| SwellPedal | all four | |
| Trap | all four | |
| Tuning | install only | tunings are not "removed", they are replaced by new tunings |