If the system drive is assigned to be #0 and the working drive is assigned to be drive #1, the above example will perform the following operation: get the APPEND command from drive #0 (the system drive), then append FILE2 from drive #1 (the working drive) to FILE1 from drive #1 and put the result in FILE3 on drive #1. As can be seen, the system drive was the default for APPEND where the working drive was the default for all other file specs listed.
Automatic drive searching causes FLEX to automatically scan the ready drives for the file specified. Hardware limitations prevent the mini floppy versions from searching for "ready" drives. For this reason, FLEX has been setup to ALWAYS assume drive 0 and 1 are ready. Thus if a mini floppy version of FLEX attempts to searcch a drive which does not have a disk laoded, it will hang up until a disk is inserted and the door closed. Alternatively, the system reset could be hit and a warm start executed (a jump to address CD03). The full size floppy version CAN detect a ready condition and will not check drives which are out of the ready state during automatic drive searching.
Automatic drive searching causes FLEX to first check drive #0 for the file specified. If not there (or if not ready in the full size version), FLEX skips to drive #1. If the first file is not found on drive #1 in the mini floppy version, FLEX gives up and a file not found error results. In the full size version FLEX continues to search on drives #2 and #3 before reporting an error.
The general syntax for the ASN command is as follows:
where <drive> is a single digit drive number or the letter A. If just ASN is typed followed by a 'RETURN', no values will be changed, but the system will output a message which tells the current assignments of the system and working drives, for example:
THE SYSTEM DRIVE IS #0
THE WORKING DRIVE IS #0
Some examples of using the ASN command are:
where the first line would set the working drive to 1 and leave the system drive assigned to its previous value. The second examples sets the system drive to 1 and the working drive to 0. Careful use of drive assignments can allow the operator to avoid the use of drive numbers on file specifications most of the time!
If auto drive searching is desired, then the letter A for automatic, should be used in place of the drive number.