Rar compresser can compress a single files that have a big size and split into multipe files like this
the question is, is if i only have 3 part like part01 - part03, is there software to extract the files, although not complete ?
Unfortunately, probably not.
The base file contains the pointers to the beginning and ends of the files in each part.
People that post to usenet have been adding "PAR" files to the uploads so that you can rebuild an archive if some parts are missing. A program like "SmartPAR" is used for it.
If the files contain recovery records, you can try to use WinRAR's repair option to see if can be rebuilt, but I've never had any success when the base file is missing.
if dat is video file u can view it ....
Well it depends on what is compressed in the rar archive. If you are downloading some kind of movies then keep the broken files tab checking does the trick and you can view part of the movie from the first rar part to check its quality and if just a single setup file then it wouldn't do with the incomplete set of rar files.