IBM 1302 Disk Storage Unit

The IBM 1302 Disk Storage was an improved version of the IBM 1301 with four times the storage capacity. It was used with the IBM 1410 Data Processing System and the 7000 series of computers. The number of tracks per inch and bits per inch in the 1302 had been doubled from the earlier 1301, resulting in a quadrupled bit capacity to 117 million 6-bit alphanumeric characters per module. A recording density of 1050 bits per inch had been achieved by reducing the thickness of the magnetic storage medium and the spacing between the recording head and disk. The track density had been doubled to 100 per inch while maintaining the same access time. Average access time to a record was 165 milliseconds, and an entire cylinder of 234,000 characters could be scanned in 1.3 seconds.