[daip] strange DELAY error

[Eric Greisen]

Andrew Biggs wrote:
> Hi there. I've recently been experiencing quite a few instances of the
> following error when I try and, say, TVLOD an image:
> 
> AIPS 2: ZMI2: DELAY 1
> AIPS 2: ZMI2: DELAY 2
> AIPS 2: ZMI2: REQUEST FOR BYTES 1 THRU = 524288
> AIPS 2: ZMI2: BEYOND EOF = 262144
> AIPS 2: ZMIO: OPER=READ LUN=16 BLKNO=           1 8-BIT-BYTES=524288
> AIPS 2: ZERROR: IN ZMI2 ERRNO = 22 (Invalid argument)
> AIPS 2: TVLOAD: MINIT DISK I/O ERROR =     3
> 
> This seems to be related to having earlier run CCEDT on the image - a
> missing CC table somehow seems to result e.g. 1 and 3 are there, but not 2.
> 
> 
> Do you have any idea what might be causing this? Can the image be
> recovered?

The DELAY messages are there to defend us from file systems that do not 
keep their file size info up to date (Lustre here at Socorro for one). 
They are real time delays of 1 sec and are done to try to prevent the 
error that follows.  The TVLOD thinks that the data file 524288 bytes 
long while it is in fact 1/2 of that.  Has the image header become 
corrupted?  Can you provide details of the CCEDT issue?  Do this 
promptly, I leave Thursday on vacation until April.

Eric