autoboot_delay
Option Category #
# SCRIPTING OPTIONS
#
Description This command is used to delay the string that you have added to the -autoboot_command. The value after is the amount of seconds to delay. This command can be useful if the system takes a while to finish booting.
Full Command autoboot_delay <integer>
Alt. Command none
Reverse Command none
Example mame64 spectrum batman -autoboot_command "j""""""\n" -autoboot_delay 5

The Sinclair Spectrum used quick keyboard shortcuts to enter commands. "j" is the quick key for Load. Any quotes need to be inside... err... quotes to be shown. Thats why there are six quotes in the command just to create the command Load "". The \n is use for a new line. The delay is there to allow for the system to finish starting up.
mame.ini Command autoboot_delay
Command Default 0
Argument Format <integer>