TransNix is the software that will control the three different processors involved
in the detector control and in the low-level data handling. These three
processors are:
the DSP 56001 processor, that sends to the detector chip the clock wave
patterns;
the chain of transputers, responsible for data acquisition,
low level data handling, and housekeeping;
the host computer,
responsible of writing
the raw data on disk, and communicating between the TransNix and the
high level software (XNIR); in the laboratory versions, it will be based on an Intel
processor, using Linux as operative system,.
The software will be written in assembler for the DSP processor, in Occam
for the transputer, while the host section will probably only consist
of the driver iserver , written in C language.
The active precesses can be gathered into four main groups. The ``Base low
module'' will act as interface to the whole syestem, and will direct
and synchronize all the other subprocesses. The ``Base high module'' will
take care of the whole flux of commands and data, to the DSP and from
the detector, and will also handle the telemetry data. The third group
of processes is run by the DSP module; it only has the task of sending the
clock signals to the detector chip, according to the wave-pattern tables,
and of controlling the integration time. The fourth group of processes
will handle the output from the analogic converters; it will temporary
store the data in the transputer RAM, it will perform basic operation
on the data, such as subtraction or coadding of various frames, and will
eventually interleave the data from the four subframes to compose the
final frame.
Further information on the software is given in
[1] and in
[6].
The final TNG version of NICS software will be fully
compliant to the TNG specification.
High level software
The interface with the user and the higher level data handling is
committed to the high level software for the laboratory version. This
will probably consist of an upgrade of the XNIR software that was
developed for ARNICA and LONGSP (the camera and the spectrometer build
and operated by the Arcetri infrared group). Such software will allow
the user to insert and control all the data required for the
observation, and to display the acquired images, by means of a system
of windows operated in the X11 environment. It will also allow
preliminary reduction of the raw data (eg. flat fielding, background
subtraction, wavelength calibration) to have a first impression of the
data quality, almost in real-time. The high level software will also
take care of communication with the telescope, so that nodding and
mosaicing will be performed automatically according to the instructions
provided by the user.
Data reduction
Although astronomers will be free to reduce the data delivered by NICS following their
preferred method, our group will provide the recipe and a set of routines
aimed at reducing the data in an optimum way according to our
experience. The set of routines will probably consist of a package of tasks
to be run within the IRAF environment. Some of the routines will be an upgrade
of the tasks written for the Near-Infrared Camera ARNICA
[7],
though significant changes will be introduced to fit NICS' features and
performances in the field of low-and high-resolution spectroscopy, polorimetry and
spectro-polarimetry.
