TECHNOLOGY
Computers Communicate by Microwave Relay Transmission at 15,000 characters per second replaces carrying of tape physically, eliminates half-day lag A microwave relay system now links a small computer operated by California Research Corp. at Richmond, Calif., with a large one at Standard Oil of California's computer center in downtown San Francisco. This system, the first in operation between separated computers in nonmilitary use, sends 15,000 characters per second back and forth between magnetic tapes in an IBM 1401 and an IBM 7090. It replaces a practice of physically transporting magnetic tape between the two computers, a process which has taken as much as half a day. Behind the system is a new General Electric machine, the TDS-90 Data Terminal. This machine scrambles magnetic tape signals into electrical impulses, suitable for microwave transmission. And, since it is a duplex machine, it also unscrambles microwave to magnetic tape signals. Two of these machines, one at each computer, send and receive simultaneously at both ends of the link. Large-scale computers like IBM's 7090 are speedy problem solvers— 240,000 calculations per second. Because of their speed, information is fed to such machines by magnetic tape. Also, output is on tape which is trans-
ferred to a printed report or punched cards. Smaller computers specifically designed to prepare and translate magnetic tape do this job. Where tape can be prepared at the site of the large computer, the tape can be merely switched from the small to the large computer. But in a decentralized organization where separated groups are working complex problems, this is not efficient. From Richmond, for instance, physical transportation across San Francisco Bay and back has not only taken half a day, but the people responsible for the problem have had to go along with it to maintain direct control. Thus the problem is not only delayed, but the people are tied to one problem during the period. The microwave link, however, puts the capability of the large computer at Richmond as well as at San Francisco.
Problem Transmitted.
COMPUTER LINK. Problems and their solutions travel by microwave relay over the 11 miles separating Standard of 42
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The link
takes over after the problem and program are set up and coded onto magnetic tape. The tape impressions are then converted to electrical impulses suitable for microwave by the TDS-90 Data Terminal. A microwave system operated by Pacific Telephone and Telegraph Co. transmits the problem
and program to the San Francisco computing center where another TDS-90 converts it back to tape. Besides saving time, the transmitting speed will add important advantages to Richmond's computing ability, Standard says. Production of programs for computing should be three times as fast because of the speed at which these can be checked out and "debugged" by actual computer trials. Exploration of many design variables should be more effective also. This will be a particular help in cases where many parameters can be altered and the most worthwhile must be selected prior to detailed design. Three other satellite computers are already tied into the center by conventional telephone line. These are in a laboratory at La Habra, Calif., and refineries at El Segundo, Calif., and Perth Amboy, N.J. Maximum transmission is 150 characters a second. Two other Standard of California computer facilities—Taft, Calif., and Houston, Tex.—are scheduled to be tied to the San Francisco center in the near future. The ultimate form of this hookup is still under study, the company says, but microwave hookup is a definite possibility.
California's research laboratory in Richmond (left) and its computer center at San Francisco headquarters
