SPA allows one to see and manipulate data contained within a disk data file known for historical reasons as the S file (henceforth, the SFILE). This data file must be initialized and created with the SPI program. See Chapter 3 for details in running this initialization program.
When the SPA data file is initialized with the SPI program, 16 internal subdirectories in which to store data are created. These are labeled S1, S2, S3, .... S16. The active or current subdirectory is shown in the SPA command line prompt. One can change the current subdirectory with the cd command. For example, if the current subdirectory is S5 as noted by the command line prompt, then the following command changes the current subdirectory to S16. S5> cd s16 The resultant command line prompt reflects this change. S16> The user can dynamically create and remove subdirectories in addition to S1-S16 with the md and rd commands. There is a limit of 90 subdirectories allowed within the SFILE. The names of these subdirectories are limited to 3 characters and can not conflict with the names of functions or previously defined subdirectories. For example, to create two additional sub directories with the names RED and SOX respectively, {S16> md red md sox To remove the SOX directory, S16> rd sox Unlike filesystems associated with UNIX, VAX/VMS and MS-DOS operating systems, there is no tree hierarchy associated with these subdirectories.