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File Structures
1.4 DATA FILES
The programs = TF IF, MOMITOR and LIS store data in an identical fashion, allowing the FEF IFT
program to work with each. The data files conform to the HPAF format, and are organized as follows:
Header
The header contains the type string in record zero, the number of records of actual data in the file in
record one, and the address of the descriptor block in record two.
The type string consists of the string
HFHF followed by a series of one or more Ms.
The number of [4 characters defines the worst case
number of items in each record. This number corresponds to the number of traces or channels in the case
ofa =TKIF or MIMI TOR file, or to the largest number of readings stored by a group in a file generated
by the [_I115 program.
The number of records indicated in record one does not represent the total number of available data
records in the file - it shows the number of records that were actually recorded.
If the data logging
sequence was aborted before all data had been collected, the file will still be valid.
Data Records
The data records contain, in order, the time of acquisition, date of acquisition, and group number, followed
by the actual data.
The time is a real number representing the number of seconds since midnight.
The
date is in v"Y'[I0I0 form, indicating the year and the day number in the year. The group number indicates
which group collected the data which follows. The group number will always be | for files generated by
STEIFF and MOMI TOR.
Descriptor Block
The descriptor block contains a tag which identifies which program generated the data file, followed by
one item for each group which contains information about the amount and origins of the data for that
group.
Files generated by = TF IFhave a tag = TF IF, followed by one item. The item is a six-character string.
The first two characters contain the string representation of the number of traces in the setup, which
should be equal to the number of Is in the type string. The third and fourth characters should read K1
and the fifth and sixth characters are the same as the first two.
Files generated by MIMI TIE have a tag MOMI TOR, followed by one item. The item is organized the
same way as for the STFIFfile.
Files generated by Ls have a tag LI: followed by one item for each group in the setup. The first two
characters in the item contain the string representation of the number of values stored by the group. The
third and fourth characters contain the string representation of the first channel in the HP 3421 A used in
the scan, or the slot number in the case of a digital byte. The fifth and sixth characters contain the string
representation of the last channel in the HP 3421A used in the scan. The channel numbers will be -1 in
the case of a custom program call.
1-7
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