95
10.1.2 File structure
There are two file categories:
−
files containing structured information, whose fields have an assigned type (
structured files
)
−
files containing “raw” data, without defined fields, or field types (
raw files
)
Raw files are distinguished by the
RAW FILE
flag
in the
record definition structure
10.1.3 Structured Files
Structured files are mostly used to save on disc the values of variables allocated in the device volatile memory.
These variables can be used to hold configuration values (
input variables
) or to hold the results of the analysis
and data logging functions (
output variables)
.
Each structured file contains one or more “
Variable definition structures”
describing the variables format and
content:
Variable definition structure
Field
Size
Field Name
Field Type
Field Description
Values
1 byte
Reserved
Unsigned integer
Reserved
0
1 byte
Descriptor list size
Unsigned integer
Size(in bytes) of the descriptor list container in the
structure
s
Descriptor 1
Descriptor 2
:
s
bytes
Descriptor
List
Descriptor m
-
A list of descriptors defining the variables stored in the
file.
-
Structured files can be of two types:
−
HOMOGENEOUS FILES containing data records sharing the same format;
−
NON HOMOGENEOUS FILES, containing data records whose format may differ
Homogeneous files contain - in the file header - a single variable definition structure.
Non-homogeneous files contain a variable definition structure per data record: their header contains only the
record definition structure.
Homogeneous and non-homogeneous files can be distinguished by the value of the NON HOMOGENEOUS
FILE
flag, in the record definition structure.
