Hi:
Partly the type of syntax you use will depend on how you are reading the "flat file" from tape -- what operating system has the tape drive physically attached. Was the tape created on the mainframe or on Unix? Is the tape file really a flat/sequential file or a VSAM file or a SAS transport file? You indicated that you were reading flat files. It is possible to read flat files or "raw data" stored on tape with SAS.
Here is an example of reading a tape file on UNIX:
http://support.sas.com/documentation/cdl/en/hostunx/61879/HTML/default/a000455940.htm
http://support.sas.com/documentation/cdl/en/hostvms/62450/HTML/default/a002222873.htm
(I only found doc on the TAPE engine for Open VMS, not Windows)
And here are some other notes:
http://support.sas.com/techsup/technote/ts473.pdf
http://support.sas.com/documentation/cdl/en/hosto390/61886/HTML/default/mvs-allexf-eft.htm
If you're going to be using a tape device attached to an MVS system, you might need to use SAS/Connect to set up your PC code to run on the MVS system so the tape can be mounted and read. Or, use techniques similar to those described here:
http://www2.sas.com/proceedings/sugi27/p108-27.pdf to read the tape file.
This may be a question best answered by Tech Support, as they can help you with the correct syntax for your particular configuration, operating system, location of tape drive and type of file.
cynthia