Ultrasonic analog input?

[sthreet]

We have ultrasonic analog input, wired based on a youtube video.

I however don't understand the parameters of Ultrasonic namehere=new Ultrasonic(a, b);

a is input, what does that mean?
b is output, what does that mean?

I tried 8, 7 and tried with the ultrasound in both analog 8 and analog 7, with the following code:

if(namehere.getRangeMM<10)
{
drive.tankDrive(1, 1);
}

I know drive.tankDrive(1, 1); works fine, as that works based on joysticks. What am I doing wrong?

Also are their good java tutorials for cameras/encoders/solenoid magnetic sensor thingies anyone know them? (By "good" I mean that it explains the api and the parameters. for example: this parameter means you have to wire the output to <analog/DIO/pwm/other> and it will reference that slot.)