The SRI ERMA Project

Introduction | Development Begins | The ERMA Computer | The Infallible Reading of Account Numbers and Final Hurdles | The Team

The ERMA Computer

"ERMA was the absolute beginning of the mechanization of business."

An ERMA machine on display at a Bank of America museum in Concord, California. (Photo courtesy of Bank of America)

The detailed design and construction of the first ERMA was a tour de force of engineering skill and ingenuity. The technologies needed were in a state of flux, and yet the machine had to be both reliable and accurate. Developed from 1950 through 1955, ERMA used magnetic drums and tapes for storage, and vacuum tubes, silicon diodes and relays for logic. Unlike other (batch-mode) machines of the period, ERMA made account data available online to validate inputs and to respond to inquiries about account status.

Moreover, because a single machine was to serve a number of users simultaneously, it was, in retrospect, one of the first time-sharing computers. The computer evolution was in its infant stage. Stored-program computers were less than two years old and still in a laboratory state. "Whirlwind," the first real-time computer, was just being assembled at Massachusetts Institute of Technology (MIT). It used magnetic core memory, a technology that was not available to SRI.

Clearly, ERMA was a breakthrough, and no existing system was close to the functionality required. One of the early technical obstacles was the check reader/sorter. Bank of America's Clark Beise made it clear to SRI's Tom Morrin that he did not want to deal with punched cards. To transfer all the check's information onto another medium would further encumber the process. Hence, the check or deposit slip itself had to be read to identify the account number, the check number or both. Because it was handwritten, the amount of the check required human entry.

Still, SRI was faced with building a check reading and sorting system that would be infallible. The check reading task was addressed by Ken Eldredge, Fred Kamphoefner, Phil Merritt and others, while the mechanical design of the sorter was done by Bill Noon.

The sorter came to handle about 10 checks per second with errors of less than one per 100,000. The sorter was the early success of the project, showing that Beise's request for a cardless system could be achieved.

The final ERMA computer contained more than a million feet of wiring, 8,000 vacuum tubes, 34,000 diodes, 5 input consoles with electronic reading devices, two magnetic memory drums, a check sorter, a high-speed printer, a power control panel, a maintenance board, 24 racks holding 1,500 electrical packages and 500 relay packages, 12 magnetic tape drives for 2,400-foot tape reels, and a refrigeration system. ERMA weighed about 25 tons, used more than 80 kW of power and required cooling by an air conditioning system.

In the spring of 1955, Bank of America was getting anxious to declare victory and wanted to announce this previously confidential effort. The bank froze the design and, while permitting post-demonstration changes, announced that the team would demonstrate the existing design "as is" in September. The pressure increased dramatically as engineering changes had to be implemented to improve system reliability and to add unscheduled functionality. By September, the engineering staff was working around the clock.

Following successful demonstrations of ERMA at SRI, the Bank of America engaged General Electric Corporation (GE) to manufacture 40 machines for installation in California. SRI worked with GE to transfer the basic processing algorithms to GE's architecture that used transistor logic and magnetic core memory. Both technologies were still in the experimental stage when SRI designed ERMA.

ERMA processed 33,000 accounts per hour, 792,000 accounts in 24 hours and five-and-half million accounts in one week. ERMA worked around the clock and did not get tired. Tom Morrin defined the new era clearly, "ERMA was the absolute beginning of the mechanization of business."

Keep reading: The Infallible Reading of Account Numbers and Final Hurdles