Date   : Sun, 12 Apr 1981102:37:00-MST
From   : W8SDZ@MIT-MC (Keith B. Petersen)
Subject: Little known CP/M calls

Dan@ML asked about BDOS calls 38 and 39 on CP/M 2.2.  These are not
implemented.  A disassembly of BDOS shows that these calls will point
to a RET (return) instruction, and thus have no effect.  They are
reserved for use with MP/M, where they have the following meanings:

Function 38:   Access drive
Function 39:   Free drive

See the MP/M manual for more details.