Hi!

JCF>I would like to read and write on the serial port of a PC (under
DOS) 
JCF>with Caml Light. Is it possible ? (I can interface C code to
achieve
JCF>it, but there may be an easier solution).

Since the PC serial programming interface has nothing like handshaking
or controlling, you have to call C-code to get good results, I fear.
Actually the easiest way is to install a "fossil" driver - that
corrects most of the defizits in the PC serial architecture, and then
use some little user primitives to access the serial interface through
this driver (it uses the same int as the bios).

bye, Georg