If you're like most of the students at Harvard, your I.D. card is just a 2 in. by 3 in. slip of plastic with a picture you'd rather forget, a nine-digit number you wish you could remember, and a little black stripe that serves absolutely no purpose.

But if you're R. Jerrold Gibson '51, those bursar's cards mean big business, and that little black stripe holds the promise of saving Harvard thousands of dollars.

But as events this week made painfully evident, Harvard has a long way to go before it can reap any benefits from its new I.D. cards: Technical difficulties forced Gibson, the director of the office of fiscal services, to abandon his plans to encode the magnetic stripe on each student's I.D. card.

Gibson's decision also makes it virtually impossible for him to follow through this spring with college-wide tests of equipment designed to limit access to University facilities.

The bursar's card merry-go-round began to revolve in September 1974, when the University unveiled its all-new bursar's card with the machine-detectable identification stripe. A brouhaha arose immediately over the use of Polaroid Corporation cards, which are used to make identification passes in South Africa. Gibson said at the time that Polaroid had been chosen because no other companies could make a card that would accept encoding.

After the Polaroid mini-controversy quieted down, the bursar's card fell out of the limelight, and no one publicly noted or mourned the passing of I.D. card encoding early in 1975. The key to this move was Widener Library's decision to drop a proposed automation of its circulation system.

Not only was Harvard not taking advantage of the new cards, but the cards even began to cause new problems this fall as an inaccurate mailing list and the long-term expiration date on the cards resulted in the mailing of about 1000 cards to former staff and faculty members.

Nonetheless, Gibson is holding tight to his hopes to eventually introduce an extensive, computerized system of bursar's card readers in dining halls, libraries, the University Health Services, and other Harvard facilities. He believes such a system would cut the costs of being a student here by eliminating illegitimate use of costly services.

Set back by the problems created by torn and bent bursar's cards at encoding tables at Monday's registration, Gibson has now set off on another tack, exploring the possibility of dropping the photographs on I.D. cards. This step would sharply reduce the cost of making and encoding cards, enabling Gibson to replace student cards annually.

Although Gibson has gone back to the drawing board, the possibility of some kind of limited encoding and equipment tests this spring is not entirely dead. The office of fiscal services made it clear yesterday that if students in a House show interest in testing the I.D. card hardware, the office will readily oblige.