uu —
TU-58/DECtape II UNIBUS cassette interface
options UUDMA
uu0 at uba0 csr 0176500 vector uurintr uuxintr
NOTE: This driver has not been ported from 4.4BSD yet.
The uu device provides access to dual DEC
    TU-58 tape cartridge drives connected to the UNIBUS via a DL-11W interface
    module.
The interface supports only block I/O to the TU-58 cassettes (see
    physio(4)). The drives are
    normally manipulated with the
    arff(8) program using the
    ``m'' and ``f'' options.
The driver provides for an optional write and verify (read after
    write) mode that is activated by specifying the ``a'' device.
The TU-58 is treated as a single device by the system even though
    it has two separate drives, ‘uu0’ and
    ‘uu1’. If there is more than one TU-58
    unit on a system, the extra drives are named
    ‘uu2’,
    ‘uu3’ etc.
Assembly language code to assist the driver in handling the receipt of data
  (using a pseudo-DMA approach) should be included when using this driver;
  specify ‘options UUDMA’ in the
  configuration file.
  - uu%d: no bp, active %d.
- A transmission complete interrupt was received with no outstanding I/O
      request. This indicates a hardware problem.
- uu%d protocol error, state=%s, op=%x, cnt=%d, block=%d.
- The driver entered an illegal state. The information printed indicates the
      illegal state, the operation currently being executed, the I/O count, and
      the block number on the cassette.
- uu%d: break received, transfer restarted.
- The TU-58 was sending a continuous break signal and had to be reset. This
      may indicate a hardware problem, but the driver will attempt to recover
      from the error.
- uu%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.
- uu%d: read stalled.
- 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.
- uu%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.
The following errors may be returned:
  - [ENXIO]
- Nonexistent drive (on open); offset is too large or bad (undefined)
      ioctl(2) code.
- [EIO]
- Open failed, the device could not be reset.
- [EBUSY]
- Drive in use.
Theuu driver appeared in
  4.2BSD.