Continous Servo; Original vs Mod, any different?

Simple question, there is any different between original continous servo motor and modificated continous servo motor?
Specially in code and programing.

Original; the servo produce from manufacturer have continous rotation ability,
Modificated; non continous servo modificate to continous

If the modification is done properly I don't see how they would be any different.

groundFungus:
If the modification is done properly I don't see how they would be any different.

So, can I use the mod continous servo to be multi turn (and stop) ???

Yes. It will start turning when you tell it to move.
It will stop turning when you tell it to stop.
You will have no position information, so you won't know where the servo output is positioned when you tell it to stop, but it will stop.

Yes. If moded properly, when you send write(90) (degrees) or writeMicroseconds(1500) the servo should stop. Less than 90 (1500) it should turn in one direction with speed proportional to the difference from 90 (1500). ie lower number faster speed. It should turn the opposite for greater than 90 (1500). You will probably have to "tune" the numbers a bit to get it to full stop. ie, it may be 96 or 84 or ?? for full stop.

groundFungus:
Yes. If moded properly, when you send write(90) (degrees) or writeMicroseconds(1500) the servo should stop. Less than 90 (1500) it should turn in one direction with speed proportional to the difference from 90 (1500). ie lower number faster speed. It should turn the opposite for greater than 90 (1500). You will probably have to "tune" the numbers a bit to get it to full stop. ie, it may be 96 or 84 or ?? for full stop.

Full stop it mean, stop with torque? I mean the motor has some power to hold a load when it stop?

I don't think so. When the motor is stopped the only holding power is the friction in the gear train. And the servo has no way of knowing if it is moved since the feedback mechanism is disabled. Can you describe your use of the servo? Maybe there is a better way of doing what you want.

groundFungus:
I don't think so. When the motor is stopped the only holding power is the friction in the gear train. And the servo has no way of knowing if it is moved since the feedback mechanism is disabled. Can you describe your use of the servo? Maybe there is a better way of doing what you want.

For bionic hand, I use worm gear so I need continous servo rather than common servo.

And this is the trick, the compensation for position feedback: I use 2 piezo ceramic disc sensors to stop the motor.
I hope when I stop it, it still have electric torque.

Actually my first hope is the mod continous servo have same code with original continous servo, so I just use the common servo library, just like arduino says:

Writes a value to the servo, controlling the shaft accordingly. On a standard servo, this will set the angle of the shaft (in degrees), moving the shaft to that orientation. On a continuous rotation servo, this will set the speed of the servo (with 0 being full-speed in one direction, 180 being full speed in the other, and a value near 90 being no movement).

That does sound right.
I have not used any servos as continuous rotation, but have read a lot.
Some users report that the speed is not linear to the angle setting.
It would be worth playing around with a pot to set the servo angle and see what speed the servo moves at.

The worm drive should provide good holding. They inherently resist being moved by outside force.