Open the Sources

Don't give in to the Dark Side

There is a growing pool of software, originally written for MS-DOS, which now becomes more and more impossible to run. People maybe liked a certain program or used it for their hobbies, but now, they have another Operating System, and they don't want to use DOS or to reboot just to use this peace of program.

This, of course, happened to me with roleplaying-related programs when I switched to Linux. I only use DOS for playing computer-games, and I only boot it when I am sure that I will need it for an hour or more. Surely not for using some DOS program which probably even runs on the commandline.

So there goes the solution: Recompile it. Simply. If there is a source, I normally do that, and so I've got quite a collection of programs which I ported from DOS to Linux. And so, I'd like everyone to tell:

Release your Sourcecodes!

It doesn't hurt you to release a source-code of some program you wrote five years ago. There is plenty of possibility to recycle old sourcecodes, even when they're written in some weird language such as BASIC.

So I take a look now at some possibilities and quirks regarding different programming languages, their implementations and their portability. Especially in regard to Unix/Linux.

Where, please?

Todays standard is C. Or some variation of it like Objective-C or C++. So the point is:

We're gonna use the GNU C-Compiler, because it's one of the best, and it's available on nearly every platform (Unix, Windows NT, OS/2, DOS, only to mention the most common ones).

GNU C or GCC comes in three different variations, as C-compiler, C++-compiler and objective-C-compiler. And then there are some add-ons (or merely pre- processors) which can translate pascal and fortran to C. So there's no such big problem translating fortran or pascal to C. So here we go examining some compilers and how their code can be translated to GCC.

Note: You cannot normally use conio.h or dos.h for programs not running on DOS. So this must be circumvented in some way.

What general problems are to expect?

What problems are to expect using specific languages?

C

Pascal

Basic

C Problems

dos.h

This one defines variable types and FAT-filesystem-specific things. Problems can arise out of different lengths of data types (16 vs 32 bits).

conio.h

conio.h (console i/o) does not exist on Unix. There is a port of conio.h, but this shouldn't be used. Instead, ncurses.h or curses.h should be used.

Peter Keel, January 1997