[daip] help regarding tape read error

[Hendrik Linz]

Dear AIPS masters,

A colleague sent me an AIPS tape with UV data. Unfortunately, I can't 
read it into AIPS. First I give you the error messages.

I was mainly interested in the 11th file on that tape, so I used UVLOD
with NFILES=10:

SUN48 > UVLOD1: Task UVLOD  (release of 15OCT99) begins
SUN48 > UVLOD1: Reading tape drive number   1
SUN48 > UVLOD1: ZTAPE: LUN 31 BEG.TAPE AT   1 OP OF ADVF/ADVF SYS ERR CODE 0000
SUN48 > UVLOD1: ERROR      5 POSITIONING TAPE
SUN48 > UVLOD1: Purports to die of UNNATURAL causes
SUN48 > UVLOD1: sun48        15OCT99 TST: Cpu=       0.0  Real=     486


> Note: IEEE floating-point exception traps enabled:
    overflow;  division by zero;  invalid operation;
 Nonstandard floating-point mode enabled
 See the Numerical Computation Guide, ieee_handler(3M), ieee_sun(3M)

-------------------------------------------------------------------------

After that I tried it without skipping files, but:

SUN48 > UVLOD1: Task UVLOD  (release of 15OCT99) begins
SUN48 > UVLOD1: Reading tape drive number   1
SUN48 > UVLOD1: ERROR      5 READING FIRST TAPE RECORD
SUN48 > UVLOD1: Purports to die of UNNATURAL causes
SUN48 > UVLOD1: sun48        15OCT99 TST: Cpu=       0.0  Real=     488

> Note: IEEE floating-point exception traps enabled:
    overflow;  division by zero;  invalid operation;
 Nonstandard floating-point mode enabled
 See the Numerical Computation Guide, ieee_handler(3M), ieee_sun(3M)

-------------------------------------------------------------------------

Also the plain PRTTP task does not work ...

PRTTP with NFILES = 10

SUN48 > PRTTP1: Task PRTTP  (release of 15OCT99) begins
SUN48 > PRTTP1: ZTAPE: LUN 31 BEG.TAPE AT   1 OP OF ADVF/ADVF SYS ERR CODE 0000
SUN48 > PRTTP1: ERROR      5 TRYING TO POSITION TAPE FOR START OF JOB
SUN48 > PRTTP1: Purports to die of UNNATURAL causes
SUN48 > PRTTP1: sun48        15OCT99 TST: Cpu=       0.0  Real=     128

AIPS 1: Resumes
AIPS 1: RETURN CODE      8 RECEIVED: STOPPING

--------------------------------------------------------------------------
PRTTP with NFILES = 0

SUN48 > PRTTP1: Task PRTTP  (release of 15OCT99) begins
SUN48 > PRTTP1: HEADER BAKF I/O ERROR =      5
SUN48 > PRTTP1: Read at least    0.000 Megabytes in       0 logical records
SUN48 > PRTTP1: Purports to die of UNNATURAL causes
SUN48 > PRTTP1: sun48        15OCT99 TST: Cpu=       0.0  Real=     240

AIPS 1: Resumes
AIPS 1: RETURN CODE      5 RECEIVED: STOPPING


---------------------------------------------------------------------------


Well, I checked the AIPS installation and the tape drive (DDS4), and this 
combination was able to read other AIPS tapes without problems, even 
DDS1 tapes (the tape in question is a DDS2). Furthermore, we use here
the 15OCT99 AIPS version, but the tape is written in January 1999, so there
should be no problems with the AIPS versions ...

Well, I guess the tape "just" got damaged somehow over the year which is 
quite sad. I just wanted to know if you can tell from the errors codes
what's going on and whether there are possibilities to make it work in
AIPS?
A more general question would be: Is it possible to read AIPS tapes at
the UNIX level, say, with special parameter combinations of the "dd" command?
(What to use for block size, density etc. ?)

Thank you very much in advance.
Best regards,
                 Hendrik Linz.