INT 21 - DR PalmDOS - GENERIC IOCTL - LOGIN SECURITY
AX = 440Dh
CX = EDC1h (category code EDh, minor code C1h)
BL = boot drive number (01h=A:,02h=B:,etc)
Return: AL = 0 if already logged in
AL <> 0 if system is still secured (not logged in)
ES:DI -> ???
Notes: This function is called by DR PalmDOS IBMBIO.COM after CONFIG.SYS
processing has finished and it has launched the LOGIN.SYS utility
(if this is not in the root of the boot drive, the undocumented
CONFIG.SYS LOGIN directive can be used to change the path and the
moment when the login prompt will be displayed).
If security is active and the user has still not logged in,
IBMBIO.COM will display an error message and halt the system.