Turbo Prolog is a quite old Prolog system that only works
with MS-DOS. This implies serious memory limitations. Also,
it uses a special Prolog dialect with typed variables and
some other restrictions that does not comply with the Edinborough
Standard . However, it is very fast, and contains a convenient
visual debugger. I once learned Prolog by observing this debugger...
Today it is more advisable to use SWI
or Quintus Prolog, given
the memory and processing resources of todays computers and
the fact that these Prolog variants are considered standard.
Please check the detailed comparison
of current Prolog system.