Converting SPSS System Files from VMS to AIX

With the planned retirement of UVMVAX, SPSS users who routinely create and use SPSS system files must convert and transfer these files to the academic AIX system. If system files are not converted and transferred to the new system before the VAX is gone, you will lose all data and information contained in these files since they will be unusable on the academic AIX system. This includes any system files you may have backed up on magnetic tape.

The Conversion and Transfer Procedure

1. Using the following SPSS program, export.sps, as an example, convert the SPSS system file to a portable file on UVMVAX.

      get file='survey.sys'
      export outfile='survey.por'
      finish
   

   Multiple system files may be converted in the same program like this:

      get file='survey1.sys'
      export outfile='survey1.por'
      get file='survey2.sys'
      export outfile='survey2.por'
      get file='survey3.sys'
      export outfile='survey3.por'
      finish
   

   Run the export.sps program to create the portable file(s) on UVMVAX:

      $ spss/output=export.lis export.sps
   

2. Transfer the portable file to the AIX system using ftp. Make sure the transfer is done in ASCII mode, not binary. In the following example, commands in italics are those you must type.

      $ ftp zoo.uvm.edu
      uvmvax Wollongong FTP User Process (Version 5.2-05)
      Trying 132.198.101.64 ...
      Connection Opened
      Using 8-bit bytes
      220 gnu.uvm.edu FTP server (UVM-1.5(3) Wed Aug 30 13:58:28 EDT 1995) ready.
      Name (gnu.uvm.edu:j_college): jcollege
      331 Password required for jcollege.
      Password:  (type in your Zoo password here)
      230 User jcollege logged in.
      *ascii
      200 Type set to A.
      *put survey.por
      200 PORT command successful.
      150 Opening ASCII mode data connection for survey.por.
      226 Transfer complete.
      Local: SYS$USER:[J_COLLEGE]SURVEY.POR;  Remote: survey.por
      325458 bytes transfered in 0.68 seconds (467.40 Kbytes/second)
      *quit
      221 Goodbye.
   

   Multiple portable files can be transferred with a single ftp command. Use mput *.por in place of put survey.por in the above example. You will be prompted for confirmation to transfer each file with a .por extension. 3. Convert the portable file back to an SPSS system file on the AIX system, using the following program, import.sps, as an example.

      import file='survey.por'
      save outfile='survey.sys'
      finish
   

   Multiple portable files can be converted back to system files in the same program.

      import file='survey1.por'
      save outfile='survey1.sys'
      import file='survey2.por'
      save outfile='survey2.sys'
      import file='survey3.por'
      save outfile='survey3.sys'
      finish
   

   Run the import.sps program to recreate the system file(s) on the AIX system:

      jcollege@gnu.uvm.edu 51>spss -m import.sps > import.lst
   

   If the program does not run and gives the message import.lst: File exists, type the following command before trying to run the program again:

      jcollege@gnu.uvm.edu 52>unset noclobber
   

Q & A

A: System files are special binary files created by SPSS when you use the SAVE or XSAVE command in SPSS. These files contain all the original data, plus any new computed or recoded variables, value labels, variable labels, formats, etc. Most UVMVAX users have followed the convention of using either .SYS or .FIL as the file extension when naming SPSS system files. If you have any files which are xxx.SYS or yyy.FIL, then these may be SPSS system files. If you named system files with something other than a .SYS or .FIL extension and now cannot tell which files are system files, you will need to use one of the techniques described in the answer to the next question.

Q: I have a file called SURVEY.SYS. How can I be certain that this is an SPSS system file?

A: There are a couple of methods to determine whether a file is an SPSS system file. First, you can run the following SPSS program. If the program runs without errors, the file is an SPSS system file. get file='survey.sys' display variables finish Second, you can use the following VMS command to get extended information about the file: dir/full survey.sys; Note the lines labelled ÒRecord format:Ó and ÒRecord attributes:Ó. If the record format states ÒFixed length 4 byte recordsÓ and the record attributes field is ÒNoneÓ, then this file is likely an SPSS system file.

Q: This conversion process sounds complicated. Is there an alternate procedure?

A: Yes. If you still have ASCII files containing the original raw data and SPSS program files which created the system file, you could simply transfer the data and program files to the new AIX system. Once there, you would just rerun the SPSS program, which would read the data from the ASCII file and recreate the system file. There is a drawback to this, however. You may have run other SPSS programs which computed new variables, recoded variables, or modified or added to the data in some way. Assuming you saved the modified data in the same system file, you would need to find all these extra SPSS programs, transfer them to the new system, and rerun them after they were transferred.

Q: I know how to do a binary file transfer with ftp. Why can't I just transfer my system files from one computer to another?

A: While you can successfully do a binary transfer of the system file, the operating system on the receiving end will not be able to interpret the information in the file. Binary files are specific to an operating system (like MS-DOS, VMS, or Unix). An SPSS system file created on UVMVAX can be used only on UVMVAX (or on another VAX/VMS system). Likewise, an SPSS system file created on Zoo can be used only on Zoo (or on another AIX system).