The "High Speed" magnetic tape system (called tape type 1) used one-inch-wide (25.4 mm) magnetic tape running at 150 inches per second, with sixteen tracks at a density of 300 bits per inch. Eight of the tracks held data, with check data on the other eight, allowing single-bit errors to be corrected and double-bit errors to be detected. Up to eight tape decks could be connected, giving a throughput of 90,000 digits per second. Spools could hold up to of tape and were of three-prong design.