class AliFMDRawWriter: public TTask

 CTOR

 Turn digits into raw data.

 Digits are read from the Digit branch, and processed to make
 three DDL files, one for each of the sub-detectors FMD1, FMD2,
 and FMD3.

 The raw data files consists of a header, followed by ALTRO
 formatted blocks.

          +-------------+
          | Header      |
          +-------------+
          | ALTRO Block |
          | ...         |
          +-------------+
          DDL file

 An ALTRO formatted block, in the FMD context, consists of a
 number of counts followed by a trailer.

          +------------------+
          | Count            |
          | ...              |
          | possible fillers |
          +------------------+
          | Trailer          |
          +------------------+
          ALTRO block

 The counts are listed backwards, that is, starting with the
 latest count, and ending in the first.

 Each count consist of 1 or more ADC samples of the VA1_ALICE
 pre-amp. signal.  Just how many samples are used depends on
 whether the ALTRO over samples the pre-amp.  Each sample is a
 10-bit word, and the samples are grouped into 40-bit blocks

          +------------------------------------+
          |  S(1)   | S(2)   | S(3)   | S(4)   |
          |  ...    | ...    | ...    | ...    |
          |  S(n)   | T(n)   | n+2    | 2AA    |
          +------------------------------------+
          Counts + possible filler

 The trailer of the number of words of signales, the starting
 strip number, the sector number, and the ring ID; each 10-bit
 words,  packed into 40-bits.

          +------------------------------------+
          |   2AAA   |  Len   |  A |  Address  |
          +------------------------------------+
          Trailer

 Note, that this method assumes that the digits are ordered.

 WRite an array of digits to disk file

 Flush and write the data header

 Simulate the ALTRO zero-suppression filter.  The data passed in
 the first array is modified, such that all suppressed channels
 are set to some value below threshold.

 If threshold == 0 zero suppression is considered disabled, and no
 action is taken.

 Constructor
@param fmd Pointer to detector object. 

 Destructor