>Assuming your tape subsystem conforms to long-established UNIX practice,
>if the read() system call specifies a read count less than the actual
>block size when reading the "raw tape" device (which is the usual one),
>you should get an I/O error since data will be lost.
while mtio(4) says that an error will be returned, many device drivers
will not return one. The only source (Tahoe) I have available to look
at (Lions is at home) says things like:
* If we were reading raw tape and the only error was that the
* record was too long, then we don't consider this an error.
unknown mode: sane