- read arguments
- check and mount image
- filename to uppercase and convert to directory format
- parse image directory and return block list
  abort on file not found.
- create file and dump the blocks
- close, unmount, exit



main
 mountImage(imageName) : input filename, returns filedescriptor
 (directory mode:
  showDir(imd) : input filedescriptor, prints directory
   blockRead(id, data, dirEntry, dirSize)
   showDirEntry(data)
 )
 convertFileName(dirFileName,fileName) : input unix-fileName, 
                                         modifies dirFileName
 findFile(imd, dirFileName)
  cmpEntry(dirPart, dFlName)
 

0000:0880 - 0000:107F - block 1
0000:1080 - 0000:187F - block 2
0000:1880 - 0000:207F - block 3
0000:2080 - 0000:287F - block 4
0000:2880 - 0000:307F - block 5
0000:3080 - 0000:387F - block 6
0007:     - 0007:FFFF - last block
