Overview
Unless stated otherwise, all items in the instrument's memory are stored in little-endian format.
Three major types of deployment information are stored in a instrument's memory:
Sample data, comprising sets of measured values from all active channels in the instrument.
Events, which are records of non-sample incidents used to aid interpretation, or for diagnostics.
Metadata, which contains meta-information about the instrument and the deployment parameters used for each schedule.
All types of data are contained in "storage objects"; a storage object may be thought of as a file. Depending on the type of memory used by the instrument, this may actually be a file in a folder that is part of a larger file system. However, not all instruments implement memory in this way, and may not allow all the common file operations, but thinking of the storage object as a file is still a useful convenience for notation.
Sample data
Sample data is stored according to the schedules executed by the configuration when acquiring the data for the deployment; there is one storage object for each schedule. Only data from the channels associated with a schedule will appear in its storage object; data from other channels will be found in the storage objects for other schedules. However, it is possible for any channel to be associated with more than one schedule, in which case its data will appear in each of the associated storage objects. A channel that is not associated with any schedule that was executed by this configuration is considered to be inactive; it will not have been sampled, and so will have no data in the memory.
The format of the sample data within a storage object for a schedule is detailed further in the Section Sample data storage format that follows.
Events
Events are typically all contained in a single storage object. Some event types apply to the entire instrument, others may apply to a single schedule, while yet others may apply only to a single channel. For example:
An event indicating a change from external power to internal batteries applies to the whole instrument.
A cast detection event would apply to a schedule.
An event indicating a change of sensor gain would apply to only a single channel.
This information is coded within the event itself, so that events may be filtered according to different criteria when retrieved.
The format of the event data within the storage object is detailed further in the Section Event data storage format that follows.
Metadata
Metadata is typically all contained in a single storage object, and includes all the information necessary to describe the state of the instrument when the deployment was enabled. This information falls into several categories, or levels, and overview of which is:
Details of the instrument that do not change over time (for example, its serial number).
Settings that apply to the whole instrument and may be changed, although once set they are modified rarely, if ever (for example, the serial baud rate).
Settings that apply to the whole instrument and may commonly be changed from one deployment to the next (for example, the start time).
The organization of schedules, groups and channels used by the configuration for this deployment.
The groups and sampling parameters used by each schedule.
The membership of channels within groups.
Details of each channel used, including calibration coefficients and any other specific information that applies.
An attempt is made to limit the metadata to information that is relevant to the deployment. Information about any channel, group or schedule may typically not appear in the metadata if the item was not used by the configuration for this deployment, even though the item is defined in the instrument.
The structure of the metadata can be quite complex, depending on the number of schedules and groups involved, but it is organized so that metadata can be filtered according to what is applicable to any particular schedule.
Not all users will need or want access to the metadata, but for those who do, the organization and format is detailed further in the Section Metadata layout that follows.
Related commands
dataset, an overview of all of the datasets stored in the instrument as well as details for an individual dataset.
download, retrieve all or part of the information for a dataset.
enable, create a dataset when the instrument is enabled for deployment.
storage, obtain general information about the instrument's data storage.