Is it possible to create cua[0-3] devices in Slink/Potato?

[Stuart Ballard <stuart@wuffies.net>]

I have a computer running mostly slink, with a small amount of potato
thrown in. It completely fails to recognise my serial mouse, no matter
what device or protocol I give it. gpmconfig instantly decides that the
modem device must be the mouse, I guess because it's the only one with
any activity. Giving it the "correct" device, ttyS1, it just gets no
activity at the next step. Putting ttyS1 in XF86Config doesn't work
either.

What is strange is that Red Hat works perfectly well on this system.
After a bit of looking, I noticed that on Red Hat, /dev/mouse was
pointing to /dev/cua1 instead of ttyS1. This reminded me that I had
similar problems when I installed Red Hat itself, which I solved by
pointing to cua1 because ttyS1 didn't work.

I know that the cua devices are obsolete under recent kernels, but I
only have the kernel that came with slink (2.0.36?). However,
/dev/MAKEDEV cua1 doesn't work. Is there any way I can create it?
Failing that, does anyone have any ideas why my mouse would work with
cua devices and not ttyS devices, and how to fix it?

Thanks in advance,
Stuart.

PS If the solution involves upgrading some components to potato, I have
no problem with this. A complete upgrade isn't possible due to bandwidth
limitations, though.