Mach Speed Trio-View 5000 max memory?

The mach speed website says, "This unit supports Micro SD cards from 1GB to 32GB." Yeah sure I can put it in and the device will know its there but will it read the whole 32GB or just a portion like other players, phones, cameras etc? And they also say,"Supports OTG function, access the files you have saved on your external drive." Does this mean I can stream from my portable/PC hard drive or just transfer files?