The Model 115 was introduced in 1973. A new version (seen here) followed two years later, with twice the disk storage capacity, a faster execution rate and larger main storage. Card reader and card punch data entry was no longer needed. Faster data entry rates resulted from the IBM 3540 diskette input/output unit (foreground). Model 115 users could attach up to eight IBM 3340 disk storage drives (background), providing an online storage capacity of up to 558.4 million characters of information.