4.3BSD - /usr/man/cat4/tu.0

TU(4)                                                                    TU(4)


NAME
       tu - VAX-11/730 and VAX-11/750 TU58 console cassette interface

SYNOPSIS
       options MRSP (for VAX-11/750’s with an MRSP prom)

DESCRIPTION
       The tu interface provides access to the VAX 11/730 and 11/750 TU58 con‐
       sole cassette drive(s).

       The interface supports only block  i/o  to  the  TU58  cassettes.   The
       devices  are  normally  manipulated with the arff(8V) program using the
       ‘‘f’’ and ‘‘m’’ options.

       The device driver is automatically included when a system is configured
       to run on an 11/730 or 11/750.

       The TU58 on an 11/750 uses the Radial Serial Protocol (RSP) to communi‐
       cate with the cpu over a serial  line.   This  protocol  is  inherently
       unreliable  as  it has no flow control measures built in.  On an 11/730
       the Modified Radial Serial Protocol is used.   This  protocol  incorpo‐
       rates flow control measures which insure reliable data transfer between
       the cpu and the device.  Certain 11/750’s have been modified to use the
       MRSP  prom  used in the 11/730.  To reliably use the console TU58 on an
       11/750 under UNIX, the MRSP prom is required.  For those 11/750’s with‐
       out  an  MRSP  prom, an unreliable but often useable interface has been
       developed.  This interface uses  an  assembly  language  ‘‘pseudo-dma’’
       routine to minimize the receiver interrupt service latency.  To include
       this code in the system, the configuration must not specify the  system
       will run on an 11/730 or use an MRSP prom.  This unfortunately makes it
       impossible to configure a single  system  which  will  properly  handle
       TU58’s  on both an 11/750 and an 11/730 (unless both machines have MRSP
       proms).

FILES
       /dev/tu0
       /dev/tu1  (only on a VAX-11/730)

SEE ALSO
       arff(8V)

DIAGNOSTICS
       tu%d: no bp, active %d.  A transmission complete interrupt was received
       with no outstanding i/o request.  This indicates a hardware problem.

       tu%d  protocol  error,  state=%s,  op=%x, cnt=%d, block=%d.  The driver
       entered an illegal state.  The information printed indicates the  ille‐
       gal  state,  operation currently being executed, the i/o count, and the
       block number on the cassette.

       tu%d receive state error, state=%s, byte=%x.   The  driver  entered  an
       illegal state in the receiver finite state machine.  The state is shown
       along with the control byte of the received packet.

       tu%d: read stalled.  A timer watching the controller detected no inter‐
       rupt  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 (11/750 only).

       tu%d:  hard  error  bn%d, pk_mod %o.  The device returned a status code
       indicating a hard error. The actual error code is shown  in  octal.  No
       retries are attempted by the driver.

BUGS
       The  VAX-11/750  console interface without MRSP prom is unuseable while
       the system is multi-user; it should be used only with the  system  run‐
       ning single-user and, even then, with caution.


4th Berkeley Distribution        May 15, 1985                            TU(4)