BlackBerry has just reported a $935 million hit in Q2 due entirely to what it's calling a "Z10 Inventory Charge" -- in other words, a charge against inventory and supply commitments for a flagship handset that is failing to sell. Echoing Microsoft's catastrophic write-down due to unsold Surface RT inventory, this single loss was enough to wipe out much of the company's quarterly revenue of $1.6 billion. When added to a further loss due to corporate restructuring, it resulted in a final GAAP loss for BlackBerry of $965 million.