In this chapter, you learned how to refer to, or point to, an external file by using a FILENAME statement. You can use the FILENAME statement whether you want to read from or write to an external file. The file can also be referenced by a quoted literal pathname. You also learned about the difference between a text file and a binary file.

You learned how to read data from an external file with the INFILE and INPUT statements, using either list or formatted input. You learned how to write your matrices to an external file by using the FILE and PUT statements. Finally, you learned how to close your files.