each order can have several pepole responsible to fullfill this order, so when a person puts into the selve his/her part of the order, using a bar code, he/she will scan it via the main computer which controls all shelves. the computer will recognize the orderid, will bling with a red light, to dictate for the user where to put the part, if the computere recogzies that all of the required compoments if fullfilled, the computer will change the light to green, which means the person that packes it and shippes it can take this order from the shelve and finishe it.