.\"	$OpenBSD: tu.4,v 1.6 2001/10/05 14:45:54 mpech Exp $
.\"	$NetBSD: tu.4,v 1.4 1996/03/03 17:14:09 thorpej Exp $
.\"
.\" Copyright (c) 1980, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
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.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
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.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
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.\"     from: @(#)tu.4	6.2 (Berkeley) 3/27/91
.\"
.Dd March 27, 1991
.Dt TU 4 vax
.Os
.Sh NAME
.Nm tu
.Nd
.Tn VAX-11/750
.Tn TU58
console cassette interface
.Sh DESCRIPTION
The
.Nm tu
interface provides access to the
.Tn VAX
11/750
.Tn TU58
console cassette drive.
.Pp
The interface supports only block
.Tn I/O
to the
.Tn TU58
cassettes.
The devices are normally manipulated with the
.Xr dd 1
program.
.Pp
The device driver is automatically included when a
system is configured to run on an 11/750.
.Pp
The
.Tn TU58
on an 11/750 uses the Radial Serial Protocol
.Pq Tn RSP
to communicate with the cpu over a serial line.
This protocol is inherently unreliable as it has no flow
control measures built in.
.Sh FILES
.Bl -tag -width /dev/tu0xx -compact
.It Pa /dev/tu0
.El
.Sh DIAGNOSTICS
.Bl -diag
.It tu%d: lost recv interrupt.
.br
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.
.El
.Sh HISTORY
The
.Nm
driver appeared in
.Bx 4.1 .
.br
A new driver showed up in
.Nx 1.1 a.
.Sh BUGS
The
.Tn VAX Ns \-11/750
console interface is unusable
while the system is multi-user; it should be used only with
the system running single-user and, even then, with caution.