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TU(4)                 NetBSD/vax Kernel Interfaces Manual                TU(4)


NAME

     tu - VAX-11/750 TU-58 console cassette interface


DESCRIPTION

     The tu interface provides access to the VAX-11/750 TU-58 console cassette
     drive.

     The interface supports only block I/O to the TU-58 cassettes.  The
     devices are normally manipulated with the dd(1) program.

     The device driver is automatically included when a system is configured
     to run on an 11/750.

     The TU-58 on an 11/750 uses the Radial Serial Protocol (RSP) to communi-
     cate with the cpu over a serial line.  This protocol is inherently unre-
     liable as it has no flow control measures built in.


FILES

     /dev/tu0


DIAGNOSTICS

     tu%d: lost recv interrupt.
     A timer watching the controller detected no interrupt for an extended
     period while an operation was outstanding.  This usually indicates that
     one or more receiver interrupts were lost and the transfer is restarted.


HISTORY

     The tu driver appeared in 4.1BSD.
     A new driver showed up in NetBSD 1.2.


BUGS

     The VAX-11/750 console interface is unusable while the system is multi-
     user, because interrupts occur at a very high priority level (spl7) and
     cannot be blocked with splbio.  Use this driver only when the system is
     running single-user and, even then, with caution.

NetBSD 2.0                       June 5, 1993                       NetBSD 2.0