Stick with DOS
Stick with DOS
I advocate sticking with MS-DOS (or FreeDOS) on that machine. DOS gives you avenues for playing around that you just don't find in more "modern" operating systems. One of the things I like about DOS is the quantity of free (or almost free) programming languages available. While not up to the abilities of GCC or other modern compilers, you can easily use one of the free Borland C or C++ compilers and/or Turbo Pascal compilers to learn programming.
A nice thing about doing this on DOS is it is more tolerant to catestrophic crashes! Just a three-finger salute (Ctrl-Alt-Del) or a flip of the power switch, and you're back in business!
I wanted to pick back up with my old assembly language programming recently, so I installed MS-DOS 6.2 on my old Dell laptop, and am happily messing things up with MASM 6
Besides, for nostalgia, you just can't beat running DOS on an old desktop computer. I still keep (and run!) an old Packard Bell 386sx-16 system, just for those times. There are tons of old games and programs all around the Internet that run on older x86 systems and DOS. Lots of nostalgia there!
Seriously, I run Linux and Unix on the systems I can, but I really don't try to cram 10 lbs. of you-know-what in a 5 lb. bag (IE: try to run Linux on anything < a 486). If you just have to try something Unix-y on this system, give Minix a shot:
http://www.minix3.org/
If you don't have at least 8 MB of RAM, you won't be able to run Minix 3, but then again, you probably won't be able to run any version of Linux either, unless you find the original version Linus wrote for his old 386
Just my $0.02