3.5 SAV Files

  As mentioned above, the SAV format is useful for saving RDAF-format data which you have read into IDL's memory and changed in some way. For example, suppose you have a high dispersion MEHI file in RDAF format. You are running out of disk space in your account, and you only really care about Mg II anyway. You have run IUESPEC to extract the region between 2790 and 2810 Å into vectors, which you may or may not have massaged in some way. You want to save that chunk of spectrum and delete the MEHI file to make room for something else. One easy way to do this is to write the data to a SAV file.

There are two disadvantages of SAV files that should be mentioned. First of all, the files are not portable. If they are FTP'ed to a different platform, they probably need to be converted using CON_SAV (see section  2.3). Secondly, they were only intended for storing the IUESIPS vectors H, W, F, E, so they are not very useful for storing NEWSIPS vectors.