Am I reading this right? It seems to say that every day, every disc that’s currently is in stock is processed so that any that need to sent to customers can be pulled out for delivery. And my intuition tells me that would be crazy.
"Then discs are scanned a second time -- if a title is requested, and around 95 percent of titles get rented at least once every 90 days, the machine separates it and sorts it out by ZIP code. (The entire inventory of the building is run through this daily, a process that alerts other warehouses of the location of every one of the 89 million discs owned by Netflix.)"
If you DON'T scan the discs every day, then you need to organize them in some fashion so that they could be picked from the shelves when an order comes in.
If you DO scan them every day, then they can just go on the shelves in random order. The scanner will automatically pick out the discs that it needs to ship that day as they go through.
So, you pay extra for machines and labor to scan every day, but you save on the added cost for sorting equipment, as well as random-accessible storage units and people/equipment to locate and pull random movies from the stacks.
This makes even more sense if, as others have suggested, most of the Netflix inventory is deployed in the field at any one time, and not sitting on the warehouse shelves.
"Then discs are scanned a second time -- if a title is requested, and around 95 percent of titles get rented at least once every 90 days, the machine separates it and sorts it out by ZIP code. (The entire inventory of the building is run through this daily, a process that alerts other warehouses of the location of every one of the 89 million discs owned by Netflix.)"