Well, you can't fit much anything else than DSL on that drive..
Again, what processor and how much RAM does it have? You need at least 8MB of RAM to run Linux and many kernels require you to have at least a 486 CPU. Looking at the hard drive size, you may not have these.
If you have a 386 CPU and 4 megs of RAM, you may be able to run MINIX 3.
If you have a 286 or less than 4MB of RAM (at least 2), then your only unix-like option is MINIX 2
If there's less then 2MB of RAM, then your only (usable) option is some flavour of DOS.