In this case Hitachi didn't have a buffered supply. The warehouses were located literally across the street. The products were palletized at Seagate's factory in quantities matching Hitachi's product lines then delivered to the warehouse in a cadence closely matching Hitachi's consumption rate. So when Hitachi placed an order, a pallet was pulled and the ownership of the serial numbers on that pallet were transferred to Hitachi as it was delivered.

The logistics firm was the buffer allowing Seagate's product rate and Hitachi's consumption to be asymmetric in nature.