Device or File Information Record
Overview
The Device or File Information Record is a record with technical and user information about a measurement device (front-end) or a signal data file.Properties
Find more information about changing properties here: linkPath
type: See descriptionThe path that points to a data stream (from a file, a device, etc.)
If this record describes a file on disk, then the Path is the file name of the file, for example C:\Measurements\RecordingFile.csv.
If this record describes a device, then the Path is some kind of connection string or device identifier, which depends on the device driver - or Path is empty.
If this record describes a device, then the Path is some kind of connection string or device identifier, which depends on the device driver - or Path is empty.
Stream Alias
type: See descriptionThe short name of one type of data file, so that it is possible to refer to the same kind of file for multiple measurements. For example: ECG.
For more information about stream aliases, please refer to link.
The stream alias should be short and must not contain spaces or other special symbols (letters and numbers only).
The stream alias should be short and must not contain spaces or other special symbols (letters and numbers only).
Caption
type: Word or phraseThe caption, title or name of the device or the file.
This string is used to inform the user about the name or
the title of this data stream.
The string is not used for machine-interpretation, see
property for that purpose.
the title of this data stream.
The string is not used for machine-interpretation, see
property for that purpose.
Data Source Type
type: Undefined [this value cannot be changed]Device or file type (what kind of device/file it is), and version information.
If this record describes a file, then the name of this type specifier is the extension of the file, for example 'csv' for files with the .CSV ending.
Source application info
type: Undefined [this value cannot be changed]Optional Information about the application and the platform that has created this data stream.
This object is used to inform the user and management programs
about the application and platform that created the stream. This information
may help to trace down the origin of this stream.
about the application and platform that created the stream. This information
may help to trace down the origin of this stream.
Reference Identifier
type: See descriptionUser defined reference to other data (e.g. a patient name or number).
This item is used to inform the user about other data sources that have a relation to this record. In practice, this will be some reference code to other files, a patient name or an experiment name.
Measurement Information
type: See descriptionOptional user defined information of recording location or recording setup (could also be a person's name to identify the one that performed the measurement).
This string is used to inform the user about the environment
in which the data stream was created. This string could hold vital
information for how to interpret the sampled data within this stream.
The use of this string (and its interpretation) is free.
It is recommended that this information is stored in the header
of a data file.
in which the data stream was created. This string could hold vital
information for how to interpret the sampled data within this stream.
The use of this string (and its interpretation) is free.
It is recommended that this information is stored in the header
of a data file.
Source Information
type: See description [this value cannot be changed]Optional information about the source of the data stream, such as exactly which recording device was used.
This string is used to inform the user about the source
of the data stream. In practice this could be a reference
to the exact data acquisition device that produced this stream,
so that it can always be tracked in relation to this data stream.
It is recommended that this information is stored in the header
of a data file.
of the data stream. In practice this could be a reference
to the exact data acquisition device that produced this stream,
so that it can always be tracked in relation to this data stream.
It is recommended that this information is stored in the header
of a data file.
Software Information
type: See description [this value cannot be changed]Optional information about the software that was used to control the device or that was used to create or change the data file.
This string is used to inform the user about the software
that was used to create this data stream. If this
string is left empty (""), then Polybench will take
version information of all relevant Polybench components
and write it to this property.
It is recommended that this information is stored in the header
of a data file.
that was used to create this data stream. If this
string is left empty (""), then Polybench will take
version information of all relevant Polybench components
and write it to this property.
It is recommended that this information is stored in the header
of a data file.
User Notes
type: See descriptionOptional user notes to the device or file.
This string is used to store user notes (text) together
with this stream. The use of this property is free.
It is recommended that this information is stored in the header
of a data file.
with this stream. The use of this property is free.
It is recommended that this information is stored in the header
of a data file.
Foot Print
type: See description [this value cannot be changed]The foot print of a device or file is a list of units per channel. Every unit is enclosed by quotation marks, and the list is comma-separated. Some channels may not have a unit, in which case empty quotation marks are used.
The foot print is technical information to specify or identify a data stream. Polybench uses this to find similar files or devices, if it does not have other information to exactly match data streams.
First Sample Number
type: Integer value [this value cannot be changed]The first sample number of the data stream. This is only relevant to signal data files, otherwise the value is -1.
-
Total Count of Samples
type: Integer value [this value cannot be changed]The total number of samples of the data stream, or -1 if the total length is not (yet) known, or if the value is irrelevant.
You can calculate the duration of the stream in seconds by dividing this value by the sample frequency.
If this record describes a device, then the total number of samples is irrelevant in most cases.
If this record describes a device, then the total number of samples is irrelevant in most cases.
Count of Samples per Block
type: Integer value [this value cannot be changed]If the data stream is divided in blocks of data, this is the number of samples in one block. Most files and devices make working sets of multiple samples for efficiency reasons.
Many storage systems tend to store or retrieve sampled data
in blocks of a fixed number of samples. The reason for this
is better performance and better control.
It is recommended to store sampled data in blocks that
are clearly marked with order and measurement information,
so that data recovery at a later date is possible. If the
samples are stored in just one block (set SamplesPerBlock = 0)
then data recovery and data re-interpretation will be difficult.
If, on the other hand, only few samples are stored per data block,
then a data file will become unnecessarily long, because of the
large number of required header blocks.
The design of the Polybench data management is based upon a fixed
block size, therefore only one SamplesPerBlock value can be set for a stream.
The reason for that is that it is recommended to use a fixed block size
in stead of a variable block size, because a fixed block size
is more easily recoverable.
in blocks of a fixed number of samples. The reason for this
is better performance and better control.
It is recommended to store sampled data in blocks that
are clearly marked with order and measurement information,
so that data recovery at a later date is possible. If the
samples are stored in just one block (set SamplesPerBlock = 0)
then data recovery and data re-interpretation will be difficult.
If, on the other hand, only few samples are stored per data block,
then a data file will become unnecessarily long, because of the
large number of required header blocks.
The design of the Polybench data management is based upon a fixed
block size, therefore only one SamplesPerBlock value can be set for a stream.
The reason for that is that it is recommended to use a fixed block size
in stead of a variable block size, because a fixed block size
is more easily recoverable.
Start Date and Time
type: Undefined [this value cannot be changed]The time and date a file was created, or when a device was first started.
This value is used to inform the user about the date and
time the recording of this data stream was started.
Note that when a new StreamInfo object is created, this
StartDatTime property is initialized with the current date and time
of the computer it was created on.
time the recording of this data stream was started.
Note that when a new StreamInfo object is created, this
StartDatTime property is initialized with the current date and time
of the computer it was created on.