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Judy Estrin

Judy Estrin

Judith (Judy) Estrin contributed to the early research and development of networking and internetworking, first as a student and engineer, and later as a manager and executive. In her early career she helped develop some of the first networking and internetworking products and forged a path into this new market that many of the major computer and communications companies of the time failed to see.

Estrin received her bachelor’s degree in Mathematics and Computer Science from UCLA and her master’s degree in Electrical Engineering from Stanford in ‘77. As a student at Stanford, she worked under Vint Cerf during the testing and implementation of the TCP protocol for the Arpanet. While at Stanford, she learned about early work on Ethernet technology in Robert Metcalfe’s class on distributed computing.

After receiving her master’s degree, Estrin went to work for Zilog, where she worked on chip architecture and computer systems. Later, Estrin managed the development of Zilog’s networking technology, ZNet. Estrin and future husband Bill Carrico ran the systems division that brought the concept of an “intelligent wire” from an early design idea, based on Bruce Hunt’s Ariel network, to the ZNet product that was introduced at the June 1980 National Computer Conference (NCC) in Anaheim. Estrin stayed on at Zilog after many of her team left to join Ralph Ungermann and Charlie Bass in their new startup. She eventually joined Ungermann-Bass as well, and was instrumental in finalizing an OEM deal with Xerox to develop an XNS compatible LAN product.

Sensing that U-B had problems focusing their business, Estrin left U-B in ’81 to co-found Bridge Communications with Carrico. Their focus was on networks and internetworking. They designed their hardware using the newly developed Motorola 68000 16-bit microprocessor. Drawing on her past experiences with ZNet, where her team had produced a winning technology, only to see it languish without the proper marketing channels, Estrin made sure they actively cultivated this emerging market. She had successfully transitioned from engineer to savvy executive. Bridge became a major player in the LAN and bridge market before merging with 3Com in ’87.

In this interview, conducted together with Bill Carrico at their home in Los Altos, CA, Estrin describes her early work as a student, engineer, and later as a business leader. She captures the excitement of the interaction between leading edge research and product development as well as the social networking that took place in the early days of Silicon Valley. In person, they were fun to be with, highly informative and knowledgeable, and careful to be sure that they had their facts straight. They were still newlyweds and they displayed the joy of being with each other.

Keywords: UCLA, Stanford, TCP, Arpanet, Zilog, Z80, ZNet, Ungermann-Bass, Xerox, XNS, Bridge Communications, 3Com

Judy Estrin Interviewed by James Pelkey 6/23/88