Preview window
When you push "Preview" button on Create window, this window appears.

Because the size of recovery files are hard to predict for most users, MultiPar has "Preview" feature. You can see the list of recovery files which you will create by the current setting. You may consider the efficiency of those files. If you are satisfied with them, you may create recovery files directly by pushing "Create" button. Or you may return to Create window by pushing "Cancel" button.

Source block usage
  This rate is a measure of block allocation. When a file size is different from a multiple of block size, the reminder in the last block of the file becomes a waste. If all source blocks are filled by file data fully, the rate becomes 100%. When it is lower than 90%, you may decrese the block size.

Recovery block consumption
  This rate is a measure of recovery file's construction. While recovery files consist of many packets, there are some packets which don't contain recovery data. If packets for recovery blocks consume most of the recovery files, the rate becomes high. When it is too low, you may decrease the number of source blocks, or limit repetition of packets.

Efficiency of recovery files
  This rate is a measure of recovering capability. For example, when the rate is 95% for recovery files of 300MB, you will be able to recover upto 285MB. Because this value is just an avarage assumption, actual possibility depends on the distribution of damage. The efficiency is important, when you save recovery files in a limited size.