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Don Loughry

Don Loughry

Donald C. (Don) Loughry joined Hewlett-Packard in 1956 and was instrumental in developing HP’s proprietary interface bus for connecting instruments, HP-IB. Loughry then led the effort to make this a standard interface through the IEEE 488 committee, which established the standard in 1978. In the 488 meetings, Loughry met Maris Graube, who was interested in promoting a standard for the evolving technologies of local computer networks. Together they attempted to convince the ANSI X3T9 committee to pursue such a standard but were unsuccessful due to the committee’s focus on mainframe computer communications.

Loughry, along with Graube and Robert Rosenthal of the NBS, moved instead to establish the standard through IEEE, and in February 1980, they held the first meeting of the IEEE 802 committee at the Jack Tar Hotel in San Francisco. Loughry joined as a representative from HP, which at the time was developing its own version of a CSMA/CD network. Loughry eventually chaired the subcommittee responsible for developing the CSMA/CD standard (802.3). HP’s support of a CSMA/CD standard was critical in the early stages of the 802 committee, when the DEC/Intel/Xerox consortium (DIX) was facing considerable opposition to its proposed Ethernet standard from proponents of token passing networks. Loughry was recruited by Robert Metcalfe and John Shoch of Xerox to act as a spokesperson in support of CSMA/CD. In support of CSMA/CD, Loughry presented research HP had done on critical issues involving the performance of CSMA/CD networks. In an 802 committee meeting in December 1980, a vote was taken to abandon the pursuit of a CSMA/CD standard, but opponents did not receive the 2/3rd majority needed, thus ensuring a path forward for the Ethernet standard along with other standards for token bus and later, token ring.

In this interview, Loughry relates his experience maneuvering through the meetings of the 802 committee and the 802.3 CSMA/CD subcommittee. He describes the many challenges of bringing the standard proposed by DIX in the first ‘Blue Book’ in line with the needs of other proponents of Ethernet; testing various implementations, especially concerning the transceiver; and finding consensus on what to make standard and what to leave unspecified. Loughry was still serving on committee 802 at the time of this interview, which took place at his office at HP.

Keywords: Hewlett-packard (HP), IEEE 488 committee, IEEE 802 committee, Ethernet, CSMA/CD

Don Loughry Interviewed by James Pelkey 7/6/88