The Origin of the “MIT License”

The “Mit License” has become a popular way of releasing copyrighted computer programs for others to use without requiring signatures or a license fee. The quoted words refer to a group of software licenses that have common ancestry and guiding principles but varying wordings. There has been some recent discussion about the origin of the “MIT License,”¹ but that discussion has been inconclusive because authoritative historical documentation has been missing or hard to find. This note provides some of that history and documentation. Being composed 35 years after the events involved, it relies primarily on my often-flaky recollections but it also offers some relevant supporting documentation found in my files and in online archives.

In the fall of 1983, the Computer Systems Research (CSR) Group of the MIT Laboratory for Computer Science (MIT–LCS)² had developed several pieces of network software that were generating outside interest and requests for both information and copies of the code. One of these pieces was David Clark’s³ BCPL implementation of a TCP/IP stack for the Xerox Alto, intended to demonstrate that TCP/IP implementations could be small, fast, and usable in an engineering workstation or a personal computer. Descended from that starting point were a translation of the BCPL code into the C language by Larry Allen⁴ for use on the Digital Equipment PDP-11 and, led by Wayne Gramlich,⁵ a TCP/IP implementation with network applications for the IBM Personal Computer (PC/IP)⁶ by John Romkey,⁷ David Bridgham,⁸ Karl Wright,⁹ Don Gillies,¹⁰ and Louis Konopelski.¹¹ Separately, Noel Chiappa¹² developed a multiprotocol network routing system, known as the C-Gateway, for the Digital Equipment LSI-11, for which Liza Martin¹³ implemented the External Gateway Protocol (EGP).¹⁴

Because the requests were coming from both university researchers and commercial organizations, there was an ongoing discussion within the group about what conditions should accompany distribution of these materials. The option of attaching a copyright notice to software and its documentation had recently been clarified by Congress and the U.S. Copyright Office. But that option raised a further question: if copyrighted, should MIT require a written contract and impose a license fee? The group’s primary goal was to influence the way networking was done, and it seemed likely that licensing revenue would

Figure 1.

Memorandum of January 10, 1984 (misdated 1983) to attorneys, proposing suggested wording for a copyright and permission notice. The cited enclosure is shown in Figure 2.

not amount to much. Anecdotal experience of other software groups at MIT–LCS also suggested that much time would be spent with attorneys preparing and then negotiating licensing agreements. Based on these considerations, we concluded that it would be better to give the software away with a copyright notice that identified where it came from and did not require any signatures.

Larry Allen and I began conversations with attorneys Bob Sullivan¹⁵ and Sib Reppert¹⁶ of the Boston law firm that at the time was handling intellectual property matters for MIT–LCS. In January 1984, Larry and I drafted proposed wording based on the idea of copyrighting the software but including with the copyright notice a permission notice that allowed anyone to use it for free. The wording borrowed ideas and phrases that had been used in the research group’s previous restricted distribution notices and it also borrowed from the copyright and permission notice that the Association for Computing Machinery had recently begun attaching to articles in its publications. Figure 1¹⁷ is a memorandum to the attorneys presenting the draft wording and Figure 2¹⁸ is an excerpt from an attachment to that memorandum, a page from a then-recent issue of the Communications of the ACM that exhibits their copyright and permission notice wording. The attorneys soon responded favorably, and on January 25, 1984, we sent an announcement describing the change in permission policy to about 25 recipients of the June 1, 1983 “please do not distribute any further” version of PC...