[daip] moving old AIPS files to new machine

[Eric Greisen]

Jennifer Donovan wrote:
> Hi AIPS experts,
> 
> I have recently gotten a new computer (a MacBook Pro running OSX 10.6.2),
> and so I have moved all of my old AIPS files from the old machines (a
> Linux box running Ubuntu 6.06 and a PowerBook G4 running OSX 10.3.9) to
> the new one. I just upgraded AIPS to 31DEC10.
> 
> I was able to configure the data directories to point to the old data
> files, and the files created on the Linux box work fine. The files created
> on the older Mac, however, give this error when I try to list the
> directories:
> 
>> ind 7
>> mc
> AIPS 1: Catalog on disk  7
> AIPS 1:  Cat Usid Mapname      Class   Seq  Pt     Last access      Stat
> AIPS 1: ZFIO: OPER = READ LUN = 15 NREC =        6
> AIPS 1: ZFI2: REQUEST FOR BYTES 5121 THRU = 6144 BEYOND EOF = 5120
> AIPS 1: ZERROR: IN ZFI2   ERRNO = 22 (Invalid argument)
>> uc
> AIPS 1: Catalog on disk  7
> AIPS 1:    Cat Usid Mapname      Class   Seq  Pt    Last access     Stat
> AIPS 1: ZFIO: OPER = READ LUN = 15 NREC =        6
> AIPS 1: ZFI2: REQUEST FOR BYTES 5121 THRU = 6144 BEYOND EOF = 5120
> AIPS 1: ZERROR: IN ZFI2   ERRNO = 22 (Invalid argument)
> 
> Is there a way to recover this data?
> 
> I did some poking around through the archives of AIPS advice from this
> group in trying to answer this, and I found a very scary message from Eric
> Greisen warning someone against a similar-sounding situation with a mixing
> of data from an SGI and a Linux box. Apparently if the "endianness" of the
> machines are different, they could actually destroy each other's data...?
> Both my new machine and the Linux machine are Intel-compatible, but the
> older Mac used a PowerPC processor. Until I hear differently, I have
> deleted all of the data created by the older Mac from the new machine --
> but is there another way to be able to recover this data without having to
> read everything out as .fits files?

As you have determined the issue is the binary format of the integer and 
floating-point data words.  SUNs and old Mac PPCs have one format and 
Intel chips (and old vaxes) have the other.  This explains the success 
of moving your Linux data to a new Mac Intel machine.

Put the data from the PPC in separate directories on your new machine 
and create parallel empty directories.  Then

cd $AIPS_ROOT
source LOGIN.CSH   (or . LOGIN.SH for bash shells)
$CDTST
RUN REBYTE

and answer the questions.  This will do a good job of switching the byte 
order for you.  Then the parallel, previously empty directories may be 
used as AIPS directories on the new machine.  Note that you cannot 
combines the old directories in any simple way, since the same file 
names are re-used in each directory.

Eric Greisen