Definitions for External Files

numeric data that is stored in binary form in an external file. Binary numbers have a base of two and are represented with the digits 0 and 1.

an older form of data storage that is no longer widely used and is not needed by most SAS users. Column-binary data storage compresses data so that more than 80 items of data can be stored. The advantage is that this method enables you to store more data in the same amount of space. Because card-image data sets remain in existence, SAS provides informats for reading column-binary data. See Reading Column-Binary Data for a more detailed explanation of column-binary data storage.

files that are managed and maintained by your operating system, not by SAS. They contain data or text as input to SAS jobs, or they are output files created as the result of SAS jobs.

External files as input to a SAS session include the following:

• records of raw data in external files in external files that you want to read into SAS as input, including data in the form of plain ASCII text files and binary files.
• programming statements in external files that you want to submit to SAS for execution.

External files as output from a SAS session include the following:

• files in which you want to store data or text, including data written out as records in plain ASCII text files or data written out in binary form.
• files created as the result of running a SAS program, including SAS log files and results from SAS procedures. For example, the PRINTTO procedure enables you to direct procedure output to an external file. Every SAS job creates at least one external file, the SAS log. SAS catalog files and ODS output destinations are also examples of external files.

binary decimal numbers that are encoded by using each byte to represent two decimal digits. Packed decimal representation stores decimal data with exact precision; the fractional part of the number must be determined by using an informat or format because there is no separate mantissa and exponent.

binary decimal numbers that are encoded so that each digit requires one byte of storage. The last byte contains the number's sign as well as the last digit. Zoned decimal data produces a printable representation.