I know that my question probably doesn't belong here but I don't know any where else to turn for help. I'm trying to run an old DOS program using DOS box turbo on Android. I can work everything without any problem on Windows 7, but I cannot figure out how to assign drives on an sd card. I have to point to a particular directory but I don't know how to identify it for a mount command.

Any help will be greatly appreciated.

Depends on your device. Some devices (ie. Galaxy SIII and S4) use the following command for external sdcard:
mount c /storage/extSdCard

and for internal storage:
mount c /mnt/sdcard

The external sd card path will be different for each device, you'll have to look it up with a filemanager or contact your device manufacturer to find it.

Find the config file in DBT and at the very bottom, unless you added lines to it, you will see the path it starts in.

I also have DoxBox Turbo on my Nexus 7 and it works great. What I can recommend is using also the Dos Box Manager - it helps to keep a different profile for every game/program.

Unfortunately, as the Nexus7 does not have a external SDCard, I can't help you to much, but the advice Mirage2005 gives should do the trick.

For instance, I got Ultima7 installed.
I use the command
mount c: /storage/emulated/0/dosgames/ultima7

I created the map dosgames for - you guessed it - my old dosgames, and placed the ultima7 game in there.

Of course, for the external sdcard, you'd need the correct path for that.

Personally, I like to use ES FILE EXPLORER, since it's free and it's a pretty good file explorer - but of course there are many others. Using something like that, it shouldn't be too hard to find the correct location.