Quote Originally Posted by Bobbler View Post
Extruder Hold - it keeps the extruder motor from being disabled by command "M103" and is of use for 3MM extruders - source - http://www.makerbot.com/sailfish/releases
Check SD Reads - sounds like it does an error check against what was received - http://jettyfirmware.yolasite.com/v73-v43.php#crc
P-Stop - looks to be so you can add an external trigger to stop the printer via hardware - http://jettyfirmware.yolasite.com/v74-v44.php#pstop
"steppers on/off - does exactly what it says.
If you have the motors on - the carriage will be rigid and you won't be able to move it around by hand. Plus the motors tend to get a bit warm :-)
With it off, the motors are only on when printing or 'jogging'. So the carriage moves freely and the motors don't get hot."

Thank you both for taking a little time to drop some knowledge on a fresh rookie.