read(2)/write(2) errno standard for physical devices

[TranKV]

To all UNIX/C gurus out there:

When using read(2)/write(2) to access a physical device in raw mode
(9-track tape devices specifically), are there a standard errno's that 
read(2)/write(2) returns to signify end of physical tapes? Or do they 
vary among UNIX versions and tape drives? If they are indeed different,
what one can do in application programs to make them portable when
changing tape drives or machines? All suggestions are appreciated.

Kim Tran
AT&T EUO