Computer to be Used In April 30 Primary

Cambridge voters in the April 30 presidential primary will vote on punch-card ballots--and an electronic voting system will be able to tabulate the results within minutes after the polls close.

An IBM computer at the office of the Harvard University Controller will count the estimated 9000 ballots. Harvard's IBM System/360, Model 30, can count ballots at the rate of 1000 a minute.

At the poll, each voter will receive a numbered ballot card and an envelope, which can be used for write-ins. Inside the voting booth, he must insert his punch card in a small IBM unit, which will enable him to punch his selection with an attached stylus.