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 communicate with
the cpu over a serial line. This protocol is inherently unreliable 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.