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TU(4) NetBSD/vax Kernel Interfaces Manual TU(4)
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tu -- VAX-11/750 TU-58 console cassette interface
The tu interface provides access to the VAX-11/750 TU-58 console cassette
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.
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.
The tu driver appeared in 4.1BSD.
A new driver showed up in NetBSD 1.2.
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 9.0 June 5, 1993 NetBSD 9.0