About me

Welcome to my web page. I made it to document some of my work on web and related Internet standards, on documents and their formats, and older work on AI and Lisp.

See my LinkedIn profile for backgrould such as education and work history, and my blog for essays I've written on various topics. I'll post on Facebook occasionally. I have one video in my YouTube channel. Email me at LMM@acm.org. You can look me up on Wikipedia, but there are lots of errors (help!).

Recent Projects

This section lists some projects that I've been working on and planning.

  • Helping to restore Interlisp-D to usability on modern OSes. I'm thinking of this as a kind of "vintage software" project, to try to recapture the sense of fluidity in the development cycle that I've not encountered since. I hope to coordinate with the Computer History Museum and/or the Internet Archive.
  • Going Remote (https://going-remote.info) is a discourse forum for people who were suddenly called to "go remote" or help others do so. An offshoot if W3C COVAD-29: Remote Meet, Work, Class Community Group, which explores ideas for helping people wanting to "go remote". Check it out!
  • Apps and other software to support PWP (People With Parkinson's). The latest attempt is to use NFC tags (near field communication) to aid in logging medications and symptoms.
  • Curate videos of my opinion in 2015 done at an IETF by Elon University School of Communications, which also has a 1995 Prediction.
  • A paper on a theory of document formats with a focus on how formats evolve over time. It covers a lot of ground. Again, comments are welcome.
  • Long-term archiving of documents. If we are going to live in a fully-digital world, we have to have a way of keeping documents for hundreds of years with little risk of accidental or malicious destruction or unintended distribution.
  • Archive all of my own stuff: papers, notes, memos, private documents, emails. Lots Of Copies Keeps Stuff Safe (LOCKSS) is my main guide: documents in DropBox, photos in iCloud, email in GMail; scan, save and then recycle all physical media.
  • Fixing up my web and social media presence. I worked with two web designers via fiverr.com to create a usable site that works well on both desktop and mobile, that is organized by topic. I've kept the use of bootstrap.js, but moved to using a bootstrap plugin for table-of-contents. I plan to link the blog and this site by relevant keywords.
  • Organize my files in the saildart archives -- looks like it requires some archeology. For example a personal history from 1973.
  • Internationalization of URLs: there are multiple, overlapping, incomplete, and incompatible standards published by organizations that don't coordinate well. One idea that I'd like to develop is an idea for a service that could tell someone thinking of creating a non-ASCII URL how currently deployed systems would treat the URL, taking into account how they display, compare or their users would transcribe the URL.
  • Explaining the jokes of RFC 2324, HTCPCP (The “HyperText Coffee Pot Control Protocol”), and what I was poking fun of, at the time. Error 418 "I'm a teapot" has taken on a life of its own. See HTCPCP Explained for a first pass.
  • Working on Open Data and Open Documents. Documents are a means for communicating information to people. Communicating information to software, not as helpful. Is it possible to extend document formats so that they can carry data in a more useful form?


I've had Parkinson's since 2004, and I am doing well (lately) living with the condition. I've previously blogged about my surgery. I've been doing some investigation of software / systems to support people with this condition (and other chronic ailments.) Parkinzon's is a complex condition that requires management of medication and exercise to stay mobile. At a retreat last year, I was encouraged by the progress that comes with focused exercise.

Web Standards

A good chunk of my career has been around Standards, especially for the web — “arguing about how the web should work”.


The key invention of the web was using URLs for hypertext. You would think the standards for URLs would be simple, but this fundamental part of he web still has problems.

  • (2015) URL problem statement and directions
  • (2015) Guidelines and Registration Procedures for New URI Schemes.
  • (2011) masinter-dated-uri The "tdb" and "duri" URI schemes.
  • (2010) ietf-iri-3987bis Internationalized Resource Identifiers (IRIs), in IRI working group (abandoned)
  • RFC 6068 "The 'mailto' URI Scheme", M. Duerst, L. Masinter, J. Zawinski, 2010.
  • RFC 4395 "Guidelines and Registration Procedures for New URI Schemes", Tony Hansen, Ted Hardie, Larry Masinter, 2006.
  • RFC 3986 "Uniform Resource Identifier (URI): Generic Syntax", Tim Berners-Lee, Roy Fielding, Larry Masinter, 2005.
  • RFC 3553 "An IETF URN Sub-namespace for Registered Protocol Parameters." Michael Mealling, Larry Masinter, Ted Hardie, Graham Klyne, 2003.
  • (until 1995) chair URI working group, defining standards for locating, naming, and describing resources on the Internet.
  • RFC 2972 "Context and Goals for Common Name Resolution", N. Popp, M. Mealling, L. Masinter, K. Sollins, 2000. Who owns a name? At the time, I was also on the technical advisory board of RealNames.
  • RFC 2732 "Format for Literal IPv6 Addresses in URL's", R. Hinden, B. Carpenter, L. Masinter. December 1999.
  • RFC 2718 "Guidelines for new URL Schemes". L. Masinter, H. Alvestrand, D. Zigmond, R. Petke. November 1999
  • (1999 talk) Problems URIs don't solve. Presentation at TWIST 99, The Workshop on Internet-scale Software Technologies, Internet Scale Naming.
  • RFC 2397 "The 'data' URL scheme." L. Masinter. August, 1998.
  • RFC 2396 "Uniform Resource Identifiers (URI): Generic Syntax." T. Berners-Lee, R. Fielding, L. Masinter, August 1998.
  • RFC 2368 "The mailto URL scheme." P. Hoffman, L. Masinter, J. Zawinski. July, 1998.
  • RFC 1738 "Uniform Resource Locators (URL)." T. Berners-Lee, L. Masinter & M. McCahill. 1994.
  • RFC 1737 "Functional Requirements for Uniform Resource Names." K. Sollins & L. Masinter. 1994.



The primary way communication happens for the Web and many applications:

Web history

Semantic Web

Formats: PDF, HTML, Forms, Metadata

What is a file format? A lot of my work has been focused on defining file formats, the standards around them, and the protocols for negotiating formats for subsequent communication.


PDF, the Portable Document Format, was invented by Adobe more than 25 years ago, making it older than the web. Perhaps there are things we'd design differently today, but PDF is solid, widely deployed, and actively maintained. For many purposes, there's nothing like it. I've helped with some related efforts:

  • PDF and Open Data W3C Community Group was established to document "best practices" for making data in PDF more accessible to simple processing using readily available tools.
  • RFC8118: updated the registration of "application/pdf" primarily to show the "owner" is now ISO (International Standards Organization) and not Adobe. (also see GitHub repo).
  • RFC7995: PDF Format for RFCs: The IETF is moving (slowly) to change its document format(s); IETF specs will be published in PDF and HTML (and XML), not just plain text. Note that the PDF file will include the XML as an attachment.


Metadata is essentially data about data. For example, for a phone call, who called whom when? For a library book, the catalog information. There are different kinds of metadata, and different ways of associating metadata with the data it describes.


Forms are an interesting component of file formats because they imply a request for information, and span the gap between User Interface and API.

Content Negotiation

IETF Aplication-Level Standards

Some standards aren't as successful, or have more narrow applicability than expected.

  • RFC 2542 "Terminology and Goals for Internet Fax." L. Masinter. 1999.
  • RFC 2534 "Media Features for Display, Print, and Fax." L. Masinter, D. Wing, A. Mutz, K. Holtman. 1999.
  • RFC 2532 "Extended Facsimile Using Internet Mail." L. Masinter, D. Wing. 1999
  • (1996) WebDAV working group.
  • Internet Printing


Computers around the world, from different origins, work in conjunction with each other because there is agreement on how they should work; there's not a separate Internet for Google, Microsoft, Amazon, or Adobe. Of course not absolutely everyone agrees; working out differences about the future is where standards work comes in.

Governance and the Internet

The primary value of the Internet comes from the fact that there is only one, and that it can connect everyone (and everything). Governance (regulation, legislation) is local and (mostly) hierarchical: city, county, state, region, country, and global. Governance of interactions is relegated to treaties, negotiation, or worse. How can anyone offer a global service and be subject to every constraint of every jurisdiction?

Cloud services

Internet of Things

  • (2001) History of Internet Personal Appliances in IETF. Short talk at IETF IPAC (Internet Personal Appliance Control) session.
  • RFC 2324, the "HyperText Coffeepot Control Protocol" (1998). A satire on the many bad API designs being proposed at the time. The Error 418 has become an Internet Meme.

Digital Preservation

How do you save documents for a long time? From life insurance policies, to plans for buildings, and personal health records.


40 years ago, it was said that Lisp was the second oldest programming language in common use (FORTRAN being the oldest). FORTRAN is still used, and so is Lisp.


From 1973 until 1988 I worked on an evolving code base for Interlisp, an integrated software development environment (IDE) for Lisp programming, written in Lisp. Most recently (since fall 2020), I've been working on the Medley Interlisp project to restore Interlisp.

Common Lisp

Artificial Intelligence

Other Links