Maximum buffer size for read from magtape?

[Carl Lowenstein]

Since the TM-11 controller has been around since forever (early 1970's)
it has a 16-bit byte count register.  The software implication of this
hardware feature is that there is no way to read or write a single record
containing more than 65536 bytes.  This same 16-bit byte count register
is present in all the emulated TM-11 hardware that I am aware of, since
there is no obvious way to extend the original controller architecture.