Application

Pascal

Free Pascal on FreeDOS; Turbo Pascal optional.

FPC installed · Working

What's installed

Free Pascal (FPC) on the FreeDOS drive — a modern, Turbo-Pascal-compatible compiler with no Error 200 bug. Its {$mode tp} compiles most classic Turbo Pascal source unchanged, and it ships a Turbo-Vision-style blue IDE close to the Borland original.

The IDE

Launch with fp. Key shortcuts:

F2 save · F3 open
Alt+F9 compile · Ctrl+F9 compile & run
Alt+F5 view program output, then any key back
Alt+X exit · Alt / F10 menu bar

Command line & hello world

Create hello.pas with edit hello.pas:

program Hello;
begin
  WriteLn('Hello, world!');
end.

Compile and run:

fpc hello.pas
hello

Note: the program ends with end. (a period), a common first stumble.

Authentic Turbo Pascal 7.0 (optional)

A separate install (not bundled with FreeDOS) that needs the Error 200 patch — TPPATCH / TP7P5FIX, or a patched Crt unit — because its delay loop overflows above ~200 MHz. FPC is the hassle-free route; TP 7.0 is the nostalgia route. Many keep both.

Reinstall gotcha

If reinstalling

FPC failed to extract the first time due to a corrupt zip and an unset TEMP. Fix: set TEMP to a writable folder on the target disk, remove the half-registered package, reinstall from a good zip. Verify with dir C:\ppc386.exe /s.