This command adds the specified subdirectory to the default data device as a suffix.
If the default program device is the same as the default data device, then this will also be altered by DDOWN.
If the default destination device is a directory device (ie. if it ends with an underscore), DDOWN also alters this (whether or not it points to another drive).
win1_ win1_C_ win1_C_include_ win1_C_objects_ win1_BASIC_ win1_QUILL_ win1_QUILL_letters_ win1_QUILL_translations win1_secret_
The above could be a directory tree on a hard disk.
DATA_USE win1_ defines win1_ as the default directory device, so WDIR will list all of the files on win1_.
DDOWN C will move into the C sub-directory, ie. DATAD$ is now win1_C_.
DDOWN include will make WDIR list all of the files on the hard disk which are prefixed by C_include_ (eg. win1_C_include_math_h).
DDOWN does not check if there are any files with the given prefix which exist.
DDOWN breaks with error -17 (error in expression) if the parameter is a resident keyword. So append an underscore to the directory name, eg. DDOWN NEW_, or specify the parameter between quote marks (eg. DDOWN ‘NEW’).
The default devices cannot exceed 32 characters (plus a final underscore) - any attempt to extend them beyond this will result in the error ‘Bad Parameter’ (error -15).