8. Software

• Low level software

  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.

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