Dell was amazing at this 10-15 years ago. They had less than 24 hours of production volume of harddisks (and other components) on their own shelves, but forced their suppliers to have them ready. Which resulted in the suppliers building warehouses close to Dell manufacturing locations, essentially offloading some of the inventory costs upstream in the supply chain. They could do that because suppliers were competing for Dell order volume. And Dell to their customers never specified the brand of the components just generic specs like 7200 rpm, 100 GB.