Transferring VMS SAS/SPSS Data to UNIX

Jeff Hayes

Social Science Computing Co-op

February 26, 1999

Problem

SAS and SPSS data sets are stored in binary Binary representations differ across

operating systems (VMS and UNIX)

Don’t forget…

About your files on VMS tapes. Files stored as SAS or SPSS data sets on tape need to be transported

For SPSS, data sets need to be based on SPSS version 4 or later

Steps to transfer data

Exporting the data set(s) on VMS (Run some descriptives!)

FTPing the data to UNIX– SPSS portable files as ASCII– SAS transport files as binary

Importing the data set(s) on UNIX (Re-run the descriptives and check the data!)

UNIX disk allocations

Most users have only one account on UNIX– /home - limited to 100 MB. Intended for mail

and program files– /aux - limit varies 200-500 MB. (See

consultant.) Intended to hold user data files– /temp/fivedays - limited by usage (disk is 4

GB)

Use compressed files on UNIX

Compressed files can greatly reduce the amount of disk space your files take up

SAS and SPSS can read compressed transportable files directly. See:– SSCC How to… #1 How to Write/Read UNIX

Compressed SAS Data Sets Directly– SSCC Publication 7-7 Using SPSS on UNIX

Translation tools

SSCC has two utilities that can read the SPSS/SAS transportable files and write files for many different software packages, e.g. Stata, Limdep, and Excel.– Stat/Transfer (WinCenter, available to any PC

in Social Science building)– DBMS/Copy (UNIX, X windows required for

graphical interface)

SPSS: Exporting data

Use a GET command to identify the data set you wish to transfer

Use an EXPORT command to create the portable file. (Recommend .por extension)

Run descriptive statistics for verifying data transfer’s success

SPSS: FTP the data

Login to UNIX and get to the directory where you want the data to end up

Start FTP (ftp eagle) and login to Eagle get staffdisk2:[100041.spss]gss7296.por gss7296.por

When completed, type “quit” to exit FTP

SPSS: Importing data

Use an IMPORT command to read the portable file on UNIX

If you wish, you can use a SAVE command to create a SPSS system file

Re-run the descriptive statistics to compare to results on VMS

SPSS: Conclusions

Consider keeping your data in a SPSS portable file. It’s easy to read in SPSS on UNIX or a PC. It can also be transferred to another package, such as Stata, using Stat/Transfer or DBMS/Copy

When transferring SPSS portable files, use FTP in ASCII mode (default between VMS and UNIX)

SAS: Exporting data I: Libnames

Use a LIBNAME statement with the xport engine and the cc=none option to identify the transport file to be created

libname moveout xport “staffdisk:[100041.sas]gss.xpt” cc=none;

SAS: Exporting data I: Libnames

Use a LIBNAME statement to identify the directory containing the SAS data set to be exported

libname movein “staffdisk2:[100041.sas]”;

SAS: Exporting data II: PROC COPY Use PROC COPY to create a transport file

from a SAS system file or library proc copy in=movein out=moveout; select gss7296;

SAS: Exporting data II: PROC COPY The SELECT subcommand copies only the file

named to the transport file Omitting the SELECT subcommand will create

a transport file containing all of the SAS data sets in the specified directory. PLEASE DON’T. Such a file can be too large. Use SSCC How to… #7 How to Write a Macro to Transport SAS Data Sets from VMS to UNIX to transfer many files.

SAS: FTP the data

Login to UNIX and get to the directory where you want the data to end up

Start FTP (ftp eagle) and login to Eagle Type binary to specify that the transport file

will be transferred in binary mode get staffdisk2:[100041.sas]gss7296.xpt gss7296.xpt

When completed, type “quit” to exit FTP

SAS: Importing data I: Libnames

Use a LIBNAME statement with the xport engine to identify the transport file to be read

libname moveout xport “/aux/j/jhayes/sas/gss7296.xpt”;

SAS: Importing data I: Libnames

Use a LIBNAME statement to identify the directory to save the imported SAS data set

libname movein “/aux/j/jhayes/sas”;

SAS: Importing data II: PROC COPY Use PROC COPY to create a SAS system

file or library from a transport file proc copy in=moveout out=movein; select gss7296;

The SELECT subcommand must refer to the exact name specified in the PROC COPY/SELECT on VMS

SAS: Conclusions

FTP transport files in binary mode. (ASCII is the default between VMS and UNIX)

Consider keeping your data in a SAS transport file. They can be compressed and read directly by SAS.

SAS transport files can also be transferred to another package, such as Stata, using Stat/Transfer or DBMS/Copy

SAS: New developments

Starting with version 7, SAS data sets (referred to as “tables”) will be platform independent

Watch SSCNews for an announcement that version 7 is available on VMS and UNIX with new SSCC publications available

Clean-up and Back-up!

Get rid of out-of-date, unneeded files before you start this process

Please back-up intermediate (.por or .xpt) files or those you are not actively using to tape (4mm or 8mm) or CD and store them off-line

Compress! Compress! Compress!

> compress gss7296.por reduces disk space used from 1,603,962 to 443,545

> compress gss7296.xpt reduces disk space used from 5,648,960 to 565,812

Good luck!

Problems? Send log files to consultant@ssc.wisc.edu or stop by during office hours

Contact consultant early to request SSCC staff assistance in transferring all VMS files to UNIX.