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
NetBSD1.2.
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.