Closed-loop systems are able to correct in order to meet target results. Normally a sensor is used to look at the output and adjust the process accordingly. This is called feedback.
A file with an extension of .DAT is known as a Data (General). These .DAT files can be opened on Windows and Apple using programs ...
Source code is often packed for download as a TAR (Tape ARchive) file, that is a standard format in the Unix/Linux world. These files have a .tar extension; they can also be compressed, the extension is .tar.gz or .tar.bz2 in these cases. There are several ways to unpack these files.