CompuServe Messages

That's pretty weird. Internal devices should be mounted internally for stability and safety alone. To run the CD ROM you would need a port manager for the port you connected it to and MicroSoft's MSCDEX 2.2, and a CD ROM driver. If they aren't bundled with your unit, you'll have to scrounge them up (MSCDEX, at least, is easy–it's included in DOS6 and also downloadable from MicroSoft's driver library). The CD ROM will require a specific driver for its make and model; the manager must be specific to the port used.