INT 2fH 4a11H BX=0008H: Get CVF Fragmentation Info

                                                         Compatibility: 6.0+ 
 Expects: AX    4a11H (mux number)
          BX    0008H (DoubleSpace fn code)
          DL    any compressed drive number (0=A, 1=B, etc.)
          ──────────────────────────────────────────────────────────────────
 Returns: AX    DoubleSpace API Error Code (0000H=success)
          BX    maximum entries in file fragment heap
          CX    available entries in file fragment heap
          ──────────────────────────────────────────────────────────────────
    Info: DoubleSpace maintains an internal list of information that
          describes the fragmentation of CVFs▲.  This fn obtains
          information about that list.

       DL on entry, is any valid compressed drive number.  A single
          fragment heap is used for all CVFs.

       CX on return, is the total size of the fragment heap.  It is the
          value of the MaxFileFragments setting in DBLSPACE.INI.

       BX on return, is the number of unused fragment entries in the file
          fragment heap.

   Notes: ■ By tracking CVF fragments internally, DoubleSpace avoids
            needing to reread the FAT of the host drive.

          ■ A CVF will be very fragmented if, during initial compression,
            there was very little free space on the disk.  By default,
            MaxFileFragments is initially set to a whopping 2600.  But
            DBLSPACE.EXE adjusts it downward (to the actual needs plus a
            fudge factor of 110) to avoid forcing DBLSPACE.BIN to allocate
            a lot of memory each time DOS boots.

          ■ You can save some memory by defragmenting your CVFs with the
            DOS 6 Defrag command; however, Defrag won't modify a mounted
            CVF.  Before defragmenting a CVF, you must unmount it (which is
            awkward for your boot drive) and change its file attributes to
            clear the hidden, system, and read-only bits.

See Also: DoubleSpace Overview
          DoubleSpace API
          INT 2fH: Multiplex Interrupt
          DOS Functions
                                    -♦-