February 6, 2020
It might be a unique opportunity to develop distributed AI in an interesting computational base.
I'll update as I find out more.
December 8, 2019
Is this typical? To see so many errors in Wikipedia articles?
- All of the Interlisp work was at Xerox. Although I was listed as a student at Stanford and didn't get my PhD until 1980, I was working at Xerox full-time after 1976.
- I had nothing to do with Interlisp-Jericho.
- There wasn't a port of Interlisp to the vax, there was an effort to build one, and I wrote a document trying to scope out how much work that was to be done. That document wasn't to "document the port".
- My work at Stanford was on the Dendral project as an employee (my Alternative Service), not as a student. The program was in Lisp.
- My work on document management was almost all at Xerox, not for Adobe. I didn't do "pioneering work on the PDF format" (for anyone).
- I remained an employee of Xerox PARC, becoming a "Principal Scientist", but never had the title "Chief Scientist" and never reported to "Xerox AI Systems".
- I wasn't "instrumental in the development of the PDF MIME type" (I helped publish it at best.)
- My work on internet standards through IETF and W3C was over many years, between Xerox, AT&T Labs and Adobe. But it was mainly a volunteer effort on my part.
- Internet standards are not published in "peer reviewed journals"; they are reviewed, but for different reasons than peer-reviewed journals.
- I never worked on Apache. I never collaborated with Nick Kew or Kim Veltman or anyone else on any book.
- The footnote references don't correspond very well to the topics discussed.
July 1, 2019
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It wasn't until I had gotten 2 or 3 that I went from "Publish" to "Delete" to "Mark as spam" (the three options offered by blogger.)
The things that distinguish these comments:
- They exist. I rarely get comments. These happen once or twice a month
- They always are Anonymous
- They always have bad english grammar.
- They don't fit any known category of spam; not promoting anything or links anywhere
- They are flattering
- They contain nothing that would associate them with the content of the blog post they are commenting on.
- This is a data communication method, using steganography based on grammatical or punctuation or word choices.
- There is some grad student running experiments / training an AI etc. based on human spam detection
- Someone is running a background check for blogs that auto-publish anonymous comments.
May 9, 2019
Dear Dr Masinter,
I am a French software engineer and have a technical question about RFC 3986, Uniform Resource Identifier (URI): Generic Syntax.
What do you mean exactly by “hierarchical data” in this paragraph?
The language "usually" in RFC 3986 indicates the text isn't normative, but rather explanatory. So the terms used may not be precise.“The path component contains data, usually organized in hierarchical form, that, along with data in the non-hierarchical query component (Section 3.4), serves to identify a resource within the scope of the URI’s scheme and naming authority (if any).”
For arbitrary URIs, interpretation of "/" and the hierarchy it established depends on the scheme. For http: and https: URIs, the interpretation depends on the server implementation. While many HTTP servers map the path hierarchy to hierarchy of file names in the server's file system, such mappings are not usually 1-1, and might vary depending on server configuration, case sensitivity or interpretation of unnormalized Unicode strings. For web clients, the WHATWG URL spec defines how web clients parse and interpret URLs (which correspond roughly to RFC 3987 IRIs).
For an idea of what was intended, a search for "hierarchical data" yields a Wikipedia entry for "Hierarchical data model" that has relevant examples and how there are many data models in use.
The choice of data model is up to your application, and you can decide for each application which model matches your use.When I look at a directed graph of resources (where resources are the vertices and links between them are the edges), I don’t know how to decide that a particular link between two resources A and B is “hierarchical” or “non hierarchical”. Should it be just antisymmetric (A → B, but not B → A)? Should it be more restrictive, for instance the inclusion relationship (A ⊃ B)? Or another property?
For instance, which of the following directed graphs of resources should I consider as having “hierarchical” links and which should I consider as having “non hierarchical” links?
1. animalia → mammalia → dog
2. Elisabeth II → Charles → William
3. 1989 → 01 → 31
4. Pink Floyd → The Dark Side of the Moon → Money
If we use antisymmetry as the criterion for being “hierarchical”, the links of all directed graphs will be “hierarchical”.
If we use inclusion as the criterion for being “hierarchical”, only the links of 1 will be “hierarchical”, since in 2 a child has two parents, in 3 a month is shared by every year and in 4 an album can be created by several artists.
This information is needed to know if we should use the path component:
or the query component:
which one of these you use depends on not one case but the entire set of data you're trying to organize.to identify a resource.
In case 1, if you're identifying properties of groups of organisms by their taxonomic designation, the namespace is by definition hierarchical, established and managed by complex rules to resolve non-hierarchical conflicts, overlaps and disagreements. But the taxonomy of rankings has 7 or 8 levels (depending on how you count), not 3, and your example says "dog" and it's not clear if you mean Canis lupus familiaris or the entire family of Canidae. The inclusion relation is not hierarchical.
In case 2, you might have a hierarchy if you restricted the relationship to "heir apparent of".
In case 3, many use the hierarchy to organize the data such that 1989/01/13 is used to identify a resource from the first of January if the year 1983.
In case 4, many music organizers sort out files by inventing a new category of "artist" for the album-artist and using "A, B, C" for albums where there are multiple arists, and "Various Artists" for "albums" that have varieties of artists for each song.
People often invent hierarchies as a way of managing access control. WebDAV includes operations based on hierarchies.
Sometimes what is desired is a combination of different data models mixed, with the hierarchical model a "default" view, and the query parameters used to search the space and redirect to a canonical hierarchical URI.
If you're defining the space for an API, the JSON-HAL design pattern adds a layer of indirection using link relations rather than URL patterns, especially in applications where the hierarchical pattern is used for high-performance web servers which use the URL syntax for optimized load-balanced servers with multiple patterns.
XXXX XXXX (name redacted)
May 8, 2019
Topic: preservationReading about the National Archives budget woes: perhaps as digital material is becoming more prevalent, the volumes of paper documents isn't growing?
What are the unique requirements of the National Archives for online storage of digital material?
Unlike most business archives, the lifetime of archived documents is measured in centuries.
The security of archives from both accidental and intentional loss is for that lifetime; unauthorized revelation most be prevented for at least decades.
For public records, LOCKSS (Lots of Copies Keeps Stuff Safe) might be a solution. Distribute copies to each state or region.
But for confidential records, the more copies, the more likely it is the information will be revealed.
But there is an approach worth investigating, using Secret Sharing where each State could maintain a separate secure facility under its own control.
This would allow some resilience to meddling, take-down, or premature release of information unless a large number of states agree.
April 9, 2019
Topic: preservationYou know the story of the horseless carriage with a buggy-whip holder (in case you needed to put a horse in front of it). But what we wound up with is a wide variety of forms: motorcycle, automobile, tank, train, etc. The transition was accompanied by corresponding developments in infrastructure.
When Xerox started its Palo Alto Research Center nearly 50 years ago, part of its mission was the Paperless Office -- a world where work was done without the use of paper.
We're still in the middle of a long transition to paperless processes from billing, statements, advertising, news, receipts, insurance, medical records, government, textbooks, fiction, with documents still playing a major role in data-based activities. In most cases, these processes are turned from using paper documents to electronic ones, with PDF being an important carrier because of its ability to straddle the divide between the paper and electronic world.
In many of these processes, we're only seeing the beginnings of transition to another phase, of data connections, where electronic documents and email are being supplanted by sharing data, and documents only generated on demand by those who are outside of the data-centric roles.
HTML may have been originally designed as a document format for scientific papers at CERN, but its primary thrust in the last decade has been as a way of delivering applications to consumers.
The problem of the digital dark age is not so much technological obsolescence as it is that there are no document by-products of work done; this is not something that can be solved by new kinds of archival documents. In the records management community, documents must have or carry their own context which allows auditing of past behavior by examining the documents the process left behind.
We need some better ways of straddling the document and data world such that data archives are produced in a way that allows it to be audited, redacted, processed, without having all of the original context. Most data channels are, for efficiency reasons, context free. Metadata (embedded or supplemental) is a document-centric way of supplying context, but it isn't enough.
January 10, 2019
April 26, 2018
The ideal is "no symptoms, steady state", and each session has gotten better. For example, the strong impulse to close my eyes is less. My remote control (here wired to the PC) allows me to adjust the overall voltage slightly, and choose between the latest and one of three previously saved programs.
They call this "programming" but it's more like debugging; not modern debugging but the old-fashioned kind, where you're pawing through core dumps and using binary search.
Here's what I think is going onThe device implanted below my right collarbone communicates wirelessly with the programmer. There are eight contacts one after another on the end of the electrodes skewering my Globus Pallidus Interna on each side, different parts of which are connected to different parts of the brain, controlling movement of my legs and feet and hands and other parts. Each electrode can emit pulses at a given frequency (up to 179 hz) for a periodic burst (I think, the "pulse width") and a given voltage or amperage. Pulses can be monopolar or bipolar (not sure, but I'm guessing either negative only or negative and positive). The bipolar signals have a narrower effect; the monopolar signals are stronger.
There's no exact map of which parts of the GPi connect to which function of the brain. I think the theory is that the pulses disrupt the beta-rhythms which synchronize the brain function. Anyway, the Boston Scientific device I have is new, giving the programmer lots of options not possible before.
February 7, 2018
was on all the forms I had to sign, describing what was done to me...
"Stereotactic image" (the 3D result of an MRI scan on Tuesday and a CT scan Friday morning)
"... guided" (the team looked at the 3D image to plan the route of the wires into my brain)
"of bilateral" (both sides)
"GPi" (globus pallidus interna -- the part of my brain they were targeting)
"deep brain" (well, it was pretty deep in there, and hard to get to)
"stimulation electrodes" (two thin cables with 8 strands each leading to 8 points within the GPi)
"with volumetric analysis" (checking the path so they don't skewer something important)
"using Mazor robot" (a device they attached to a 'platform' that was screwed into my skull first thing Friday morning after first making me a numb-skull, then drilling pilot holes and screwing in; the Mazor robot then guides the surgery exactly)
"and implantation" (this one goes in a little pocket they cut in my chest)
"of right" (only one)
"infraclavicular" (under my collar bone, the electrode leads pushed under scalp, neck skin, down chest)
"pulse generator" (the thing that will send pulses to the electrodes)
Right now my brain is recovering from the trauma of this disturbance... my Parkinson's symptoms are mainly worse than usual -- both hands shaking, having trouble standing, using a walker to scoot around the house, speech soft and distorted enough that Alexa doesn't understand me, mild headache, among other indignities.
Today I get to shower! Yay!
My appointment for having the whole thing turned on and to start tuning the pulses to my body is February 16th. Happy Birthday!
The process of fine tuning can take 6 months of appointments every two weeks. Each of 8 leads on each side, with their own pulse intensity, frequency and width ... I'm assuming there's some method to it, will let you know.
January 25, 2018
But progressive diseases progress, and interfere with getting on with life.
I'm mainly risk-averse, but (after declining 5 years ago) I'm now scheduled next week for a surgical treatment called "Deep Brain Stimulation": like a pacemaker, but for the brain rather than the heart, and more of a pace-disruptor than -maker.
The procedure is described as "minimally invasive" and "reversible" and it's been done 100,000 times (300 by my surgeon). But still, it requires MRI and CAT scan to place wires to the exact spot without hitting good brain or blood vessels. (I got a Rift VR tour of some patient's anonymized brain as part of the explanation.)
Besides the wires in my brain ("Will I be able to listen to the radio without a radio?"), there will be wires under skin from scalp down to a not-so-tiny controller implanted -- wirelessly charged and programmed, battery rated to last 15 years. The "programming" usually takes months of adjustment.
I remember ~40 years ago admiring someone's programming skills, to the point I told people "he's so good I'd let him program my pacemaker". I'm not going to ask Boston Scientific to review their source code, but I do hope they aspire to better than "five nines".
Wish me luck...
1/31 added: for all the good wishes, expressed and felt: thank you, its meant a lot...
October 22, 2017
I was dismayed to see a twitterstorm of complaints about the ODI report on PDF and data.
Whether something is "open" depends on the tools you have, as I explore in Open Data and Documents, the scale doesn't match what people actually value.
I love Twitter. I think the twitter responses have been useful in at least reaching the user community. Thanks.
Join in on the discussion.
October 21, 2017
September 10, 2016
Some background about PDFEveryone has heard of PDF, but I'm not sure there's widespread understanding of its role and history. Wikipedia PDF isn't too bad; page independent data structures but based on Postscript, a way of getting licenses to embed fonts, first released in 1993. Originally a "distill" of a printed page, over the years, features were added: forms, 3D, compression, reflow, accessibility.
PDF is over 20 years old ... "as old as the Web"-- I first heard about it at GopherCon '93. Has it run its course, time for something new? But PDF supplies a unique solution for an application that spans the work between paper documents and electronic, and assurances of fidelity: if I send you a document, and you say you got it and read it (using a conforming reader) then I know what you saw.
MIME typesIn email and web, file types are labeled by a two part label, like text/html, image/jpeg, application/pdf. This "Internet Media Type" is (supposed to be) used in content-type headers in email and web as a way for the sender to say how a receiver should interpret the content (except for "sniffing" but that's another blog post).
There's an official list of media types managed by IANA (in the news lately for other reasons, another blog post). IANA, Internet Assigned Numbers[sic] Auhority, is in charge of maintaining the
registries, as directed by the IETF.
IETF has a different decision-making process than other standards groups. However, as usual, the process involves creating and distributing a draft, and asking for comments. Comments need to be responded to, even if you don't make changes because of the comment. Different kinds of documents have different criteria for advancement, and it's sometimes hard to figure out what rules apply.
Getting draft-hardy-pdf-mime to RFCI got into updating the registration of PDF a while back, while working on "PDF for RFCs", and, after consultation, took the path of revising the RFC which authorized the current registration, RFC 3778, in the form of a document that replaced 3778, including the registration template for application/pdf . That's the document I'm trying to get passed.
There were lots of comments during the review period, and I responded to most of them last week, in a single email.
Which process?I won't go into the detailed rules, but the path we chose involved getting IESG approval for an Informational specification, one of the paths laid out in RFC 6838, which lays out the rules for the IANA media type registry.
But which rules apply? RFC 6838 Section 3.1 for types "registered by a recognized standards-related organization using the 'Specification Required' IANA registration policy [RFC5226]"? Or do we follow Section 6.1, "in cases where the original definition of the scheme is contained in an IESG-approved document, updates of the specification also requires IESG approval."?
And does the "DISCUSS" laid on the document's approval meet any of the criteria of the rules for a DISCUSS?
But I'd like to accommodate the common request that the document say more about security of PDF software. It's well-known that PDF has been a vector for several infamous exploits... why can't we say more?
"Security Considerations"IETF has an unusual policy of requiring ALL documents (https://tools.ietf.org/html/rfc3552 Section 5) to consider security and document threats and possible mitigations. ISO has no such rule; security is considered the responsibility of the implementation. W3C nominally does through TAG review, I think, but WHATWG is more haphazard. The question remains: does a conforming implementation require that the implementation expose the user to security risks.
I'm sure we could say more. And if this were a new registration or the PDF spec itself I'd try. But application/pdf has been around over 20 years, the exploits and their prevention publicized.
But there is no single valid account of software vulnerabilities; the paper suggested (in a COMMENT, not a DISCUSS) isn't anything I could cite; I disagree with too many parts.
I’ll go back to the question of the purpose of “Security Considerations” in MIME registrations; for whom should it be written? For a novice, it is not enough. For an expert, you wind up enumerating the exploits that are understood and can be explained. The situation is fluid because the deployment of browser-based PDF interpreters is changing for desktop and mobile, and PDF is just another part of the web.
I agreed with the reasoning behind the requirement, that requiring everyone to write about Security might make them think a little more about security.
But I think there’s another view, that Security is a feature of the implementation. It’s the implementation’s job to mitigate vulnerabilities. So any security problems, blame the implementation, not the protocol. And the implementors need to worry about not writing buggy code, not just about security per se.
And there is no point of saying “write your implementations carefully”, because there are so many ways to write software badly. Talking about the obvious easy-to-describe exploits isn’t really useful, because we know how to avoid those.
Now perhaps this is just "don't set a bad precedent". So maybe the clue is to follow text/html, and suggest that "entire novels" have been written about PDF security, but not here in the Internet Media Type registration.
February 15, 2015
But it fits into the need to have and build community, and the mechanism for community requires periodic acknowledgement. We engage in sharing our humanity (everyone has a birthday) by greeting. Hello, goodbye, I'm here, poke. But not too often, once a year is enough.
I wrote about standards and community yesterday on the IETF list, but people didn't get it.
Explaining that message and its relationship to birthday greetings is hard.
The topic of discussion was "Updating BCP 10 -- NomCom ELEGIBILITY".
- IETF : group that does Internet Standards
- BCP10: the unique process for how IETF recruits and picks leadership
- NOMCOM: the "Nominating Committee" which picks leadership amongst volunteers
- elegibility: qualifications for getting on the NOMCOM
Creating effective standards is a community activity to avoid the Tragedy of the Commons that would result if individuals and organizations all went their own way. The common good is “the Internet works consistently for everyone” which needs to compete against “enough of the Internet works ok for my friends” where everyone has different friends.
For voluntary standards to happen, you need rough consensus — enough people agree to force the remainder to go along.
It’s a community activity, and for that to work there has to be a sense of community. And video links with remote participation aren’t enough to create a sense of community.
There are groups that purport to manage with minimal face-to-face meetings, but I think those are mainly narrow scope and a small number of relevant players, or an already established community, and they regularly rely heavily on 24/7 online chat, social media, open source tools, wikis which are requirements for full participation.
The “hallway conversations” are not a nice-to-have, they’re how the IETF preserves community with open participation.
One negative aspect of IETF “culture” (loosely, the way in which the IETF community interacts) is that it isn’t friendly or easy to match and negotiate with other SDOs, so we see the WHATWG / W3C / IETF unnecessary forking of URL / URI / IRI, encodings, MIME sniffing, and the RFC7159-JSON competing specs based at least partly on cultural misunderstandings.
The main thing nomcom needs to select for is technical leadership (the skill of getting people to follow) in service of the common good). And nomcom members should have enough experience to have witnessed successful leadership. One hopes there might be some chance of that just by attending 3 meetings, although the most effective leadership is often exercised in those private hallway conversations where compromises are made.
November 20, 2014
Every speech is a speech act.
Truth is too simple, make belief fundamental.
Changing the model helps think about securityPart of the problem with security and authorization is we don't have a good model for reasoning about it. Usually we divide the world into "Good guys" and "bad guys": Good guys make true statements ("this web page comes from bank trustme") while bad guys lie. (Let's block the bad guys.) By putting trust and ambiguity at the base of the model and not as an after-patch we have a much better way of describing what we're trying to accomplish.
Inference, induction, intuition are just different kinds of processing
Every identifier is intrinsically ambiguous
URNs are not 'permanent' nor 'unambiguous', they're just terms with a registrar
Metadata, linked data, are speech acts too.
September 14, 2014
This is about the IANA protocol parameter registries. Over in firstname.lastname@example.org people are worrying about preserving the IANA function and the relationship between IETF and IANA, because it is working well and shouldn't be disturbed (by misplaced US political maneuvering that the long-planned transition from NTIA is somehow giving something away by the administration.)
Meanwhile, over in email@example.com, there's a discussion of the Encodings document, being copied from WHATWG's document of that name into W3C recommendation. See the thread (started by me), about the "false statement".
Living Standards don't need or want registries for most things the web use registries for now: Encodings, MIME types, URL schemes. A Living Standard has an exhaustive list, and if you want to add a new one or change one, you just change the standard. Who needs IANA with its fussy separate set of rules? Who needs any registry really?
So that's the contradiction: why doesn't the web need registries while other applications do? Or is IANAPLAN deluded?
September 9, 2014
Way back when (1995), I spec'ed a way of doing "file upload" in RFC1867. I got into this because some Xerox printing product in the 90s wanted it, and enough other folks in the web community seemed to want it too. I was happy to find something that a Xerox product actually wanted from Xerox research.
It seemed natural, if you were sending files, to use MIME's methods for doing so, in the hopes that the design constraints were similar and that implementors would already be familiar with email MIME implementations. The original file upload spec was done in IETF because at the time, all of the web, including HTML, was being standardized in the IETF. RFC 1867 was "experimental," which in IETF used to be one way of floating a proposal for new stuff without having to declare it ready.
After some experimentation we wanted to move the spec toward standardization. Part of the process of making the proposal standard was to modularize the specification, so that it wasn't just about uploading files in web pages. Rather, all the stuff about extending forms and names of form fields and so forth went with HTML. And the container, the holder of "form data"-- independent of what kind of form you had or whether it had any files at all -- went into the definition of multipart/form-data (in RFC2388). Now, I don't know if it was "theoretical purity" or just some sense of building things that are general purpose to allow unintended mash-ups, but RFC2388 was pretty general, and HTML 3.2 and HTML 4.0 were being developed by people who were more interested in spec-ing a markup language than a form processing application, so there was a specification gap between RFC 2388 and HTML 4.0 about when and how and what browsers were supposed to do to process a form and produce multipart/form-data.
February of last year (2013) I got a request to find someone to update RFC 2388. After many months of trying to find another volunteer (most declined because of lack of time to deal with the politics) I went ahead and started work: update the spec, investigate what browsers did, make some known changes. See GitHub repo for multipart/form-data and the latest Internet Draft spec.
Now, I admit I got distracted trying to build a test framework for a "test the web forward" kind of automated test, and spent way too much time building what wound up to be a fairly arcane system. But I've updated the document, and recommended its "working group last call". The only problem is that I just made stuff up based on some unvalidated guesswork reported second hand ... there is no working group of people willing to do work. No browser implementor has reviewed the latest drafts that I can tell.
I'm not sure what it takes to actually get technical reviewers who will actually read the document and compare it to one or more implementations to justify the changes in the draft.
Go to it! Review the spec! Make concrete suggestions for change, comments or even better, send GitHub pull requests!
September 7, 2014
One of the main inventions of the Web was the URL. And I've gotten stuck trying to help fix up the standards so that they actually work.
The standards around URLs, though, have gotten themselves into an organizational political quandary to the point where it's like many other situations where a polarized power struggle keeps the right thing from happening.
Here's an update to an earlier description of the situation:
URLs were originally defined as ASCII only. Although it was quickly determined that it was desirable to allow non-ASCII characters, shoehorning utf-8 into ASCII-only systems was unacceptable; at the time, Unicode was not so widely deployed, and there were other issues. The tack was taken to leave "URI" alone and define a new protocol element, "IRI"; RFC 3987 published in 2005 (in sync with the RFC 3986 update to the URI definition). (This is a very compressed history of what really happened.)
The IRI-to-URI transformation specified in RFC 3987 had options; it wasn't a deterministic path. The URI-to-IRI transformation was also heuristic, since there was no guarantee that %xx-encoded bytes in the URI were actually meant to be %xx percent-hex-encoded bytes of a utf8 encoding of a Unicode string.
To address issues and to fix URL for HTML5, a new working group was established in IETF in 2009 (The IRI working group). Despite years of development, the group didn't get the attention of those active in WHATWG, W3C or Unicode consortium, and the IRI group was closed in 2014, with the consolation that the documents that were being developed in the IRI working group could be updated as individual submissions or within the "applications area" working group. In particular, one of the IRI working group items was to update the "scheme guidelines and registration process", which is currently under development in IETF's application area.
Independently, the HTML5 specs in WHATWG/W3C defined "Web Address", in an attempt to match what some of the browsers were doing. This definition (mainly a published parsing algorithm) was moved out into a separate WHATWG document called "URL".
The world has also moved on. ICANN has approved non-ascii top level domains, and IDN 2003 and 2008 didn't really address IRI Encoding. Unicode consortium is working on UTS #46.
The big issue is to make the IRI -to-URI transformation non-ambiguous and stable. But I don't know what to do about non-domain-name non-ascii 'authority' fields. There is some evidence that some processors are %xx-hex-encoding the UTF8 of domain names in some circumstances.
There are four umbrella organizations (IETF, W3C, WHATWG, Unicode consortium) and multiple documents, and it's unclear whether there's a trajectory to make them consistent:
The IRI working group closed, but work can continue in the APPS area working group. Documents sitting needing update, abandoned now, are three drafts (iri-3987bis, iri-comparison, iri-bidi-guidelines) intended originally to obsolete RFC 3987.
Other work in IETF that is relevant but I'm not as familiar with is the IDN/IDNA work for internationalizing domain names, since the rules for canonicalization, equivalence, encoding, parsing, and displaying domain names needs to be compatible with the rules for doing those things to URLs that contain domain names.
In addition, there's quite a bit of activity around URNs and library identifiers in the URN working group, work that is ignored by other organizations.
W3CThe W3C has many existing recommendations which reference the IETF URI/IRI specs in various ways (for example, XML has its own restricted/expanded allowed syntax for URL-like-things). The HTML5 spec references something, the TAG seems to be involved, as well as the sysapps working group, I believe. I haven't tracked what's happened in the last few months.
Unicode consortiumEarly versions of #46 and I think others recommends translating toAscii and back using punycode ? But it wasn't specific about which schemes.
From a user or developer point of view, it makes no sense for there to be a proliferation of definitions of URL, or a large variety URL syntax categories. Yes, currently there is a proliferation of slightly incompatible implementations. This shouldn't be a competitive feature. Yet the organizations involved have little incentive to incur the overhead of cooperation, especially since there is an ongoing power struggle for legitimacy and control. The same dynamic applies to the Encoding spec, and, to a lesser degree, handling of MIME types (sniffing) and multipart/form-data.
September 6, 2014
And my curiosity satisfied, I 'get' blogging, tweeting, facebook posting, linking in, although I haven't tried pinning and instagramming. And I'm not sure what about.me is about, really, and quora sends me annoying spam which tempts me to read.
Meanwhile, I'm hardly blogging at all; I have lots of topics with something to say. Meanwhile Carol (wife) is blogging about a trip; I supply photo-captions and Internet support.
So I'm going to follow suit, try to blog daily. Blogspot for technical, Facebook for personal, tweet to announce. LinkedIn notice when there's more to read. I want to update my site, too; more on that later.
September 10, 2013
Faster is better, but faster for whom?It should be no surprise that using software is more pleasant when it responds more quickly. But the effect is pronounced and the difference between "usable" and "just frustrating". For the web, the critical time is between when the user clicks on a link and the results are legible and useful. Studies (and others) show that improving page load time has a significant effect on the use of web sites. And a primary component of web speed is the network speed: not just the bandwidth but, for the web, the latency. Much of the world doesn't have high-speed Internet, and the web is often close to unusable.
The problem is -- faster for whom? In general, when optimizing something, one makes changes that speed up common cases, even if making uncommon cases more expensive. Unfortunately, different communities can disagree about what is "common", depending on their perspective.
Clearly, connection multiplexing helps sites that host all of their data at a single server more than it helps sites that open connection to multiple systems.
It should be a good thing that the protocol designers are basing optimizations by measuring the results on real web sites and real data. But the data being used risks a bias; so far little of the data used has been itself published and results reproduced. Decisions in the working group are being made based on limited data, and often are not reproducible or auditable.
Flow control at multiple layers can interfereThis isn't the first time there's been an attempt to revise HTTP/1.1; the HTTP-NG effort also tried. One of the difficulties with HTTP-NG was that there was some interaction between TCP flow control and the framing of messages at the application layer, resulting in latency spikes. And those working with SPDY report that SPDY isn't effective without server "prioritization", which I understand to be predictively deciding which resources the client will need first, and returning their content chunks with higher priority for being sent sooner. While some servers have added such facilities for prioritization and prediction, those mechanisms are unreported and proprietary.
ForkingWhile HTTP/2.0 started with SPDY, SPDY development development continues independently of HTTP/2.0. While the intention is to roll good ideas from SPDY into HTTP/2.0, there still remains the risk that the projects will fork. Whether the possibility of forking is itself positive or negative is itself controversial, but I think the bar should be higher.
Encryption everywhereThere is a long-running and still unresolved debate around the guidelines for using, mandating, requiring use of, or implementation of encryption, in both HTTP/1.1 and HTTP/2.0. It's clear that HTTP/2.0 changes the cost of multiple encrypted connections to the same host significantly, thus reducing the overhead of using encryption everywhere: Normally, setting up an encrypted channel is relatively slow, requiring a lot more network round trips to establish. With multiplexing, the setup cost only happens once, so encrypting everything is less of a problem.
But there are a few reasons why that might not actually be ideal. For example, there is also a large market for devices which monitor, adjust, redirect or otherwise interact with unencrypted HTTP traffic; a company might scan and block some kinds of information on its corporate net. Encryption everywhere will have a serious impact for sites that have these interception devices, for better or worse. And adding encryption in a situation where the traffic is already protected is less than ideal, adding unnecessary overhead.
In any case, encryption everywhere might be more feasible with HTTP/2.0 than HTTP/1.1 because of the lower overhead, but it doesn't promise any significant advantage for privacy per se.
Need realistic measurement data
To insure that HTTP/2.0 is good enough to completely replace HTTP 1.1, it's necessary to insure that HTTP/2.0 is better in all cases. We do not have agreement or reproducable ways of measuring performance and impact in a wide variety of realistic configurations of bandwidth and latency. Measurement is crucial, lest we introduce changes which make things worse in unanticipated situations, or wind up with protocol changes that only help the use cases important to those who attend the meetings regularly and not the unrepresented.
HTTP Started Simple
- Using DNS, client get the IP address of the server in the URL
- opens a TCP connection to that server's address on the port named in the URL
- client writes "GET" and the path of the URL onto the connection
- the server responds with HTML for the page
- the client reads the HTML and displays it
- the connection is closed
While each header has its uses and justification, and many are optional, headers add both size and complexity to every HTTP request. When HTTP headers get big, there is more chance of delay (e.g., the request no longer fits in a single packet), and the same header information gets repeated.
Many More Requests per Web Page
HTTP is stateless
Neither client nor server need to allocate memory or remember anything from one request/response to the next. This is an important characteristic of the web that allows highly popular web sites to serve many independent clients simultaneously, because the server need not allocate and manage memory for each client. Headers must be repeatedly sent, to maintain the stateless nature of the protocol.
Congestion and Flow ControlFlow control in TCP, like traffic metering lights, throttles a sender's output to match the receivers capability to read. Using many simultaneous connections does not work well, because the streams use the same routers and bridges which must manage the streams independently, but the TCP flow control algorithms do not, cannot, take into account the other traffic on the other connections. Also, setting up a new connection potentially involves additional latency, and opening encrypted connections is even slower since it requires more round-trips of communication of information.
HTTP/2.0 builds on HTTP/1.1; for the most part, it is not a reduction of the complexity of HTTP, but rather adds new features primarily for performance.
Header CompressionThe obvious thing to do to reduce the size of something is to try to compress it, and HTTP headers compress well. But the goal is not just to speed transmission, it's also to reduce parse time of the headers. The header compression method is undergoing significant changes.
Push vs. PullA "push" is when the server sends a response that hadn't been asked for. HTTP semantics are strictly request followed by response, and one of the reasons why HTTP was considered OK to let out through a firewall that filtered out incoming requests. When the server can "push" some content to clients even when the client didn't explicitly request it, it is "server push". Push in HTTP/2.0 uses a promise "A is what you would get if you asked for B", that is, a promise of the result of a potential pull. The HTTP/2.0 semantics are developed in such a way that these "push" requests look like they are responses to requests not made yet, so it is called a "push promise". Making use of this capability requires redesigning the web site and server to make proper use of this capability.
With this background, I can now talk about some of the ways HTTP/2.0 can go wrong. Coming up!
September 6, 2013
It was great to have so many knowledgeable implementors working on live interoperability: 30 people from around the industry and around the world came, including participants from Adobe, Akamai, Canon, Google, Microsoft, Mozilla, Twitter, and many others representing browsers, servers, proxies and other intermediaries.
It's good the standard development is being driven by implementation and testing. While testing across the Internet is feasible, meeting face-to-face helped with establishing coordination on the standard.
I do have some concerns about things that might go wrong, which I'll also post soon.
July 21, 2013
Now, we wanted to make this a joint publication, but ... where to host it? Here, Ashok's personal blog, Adobe's, the W3C?
Well, rather than including the post here (copying the material) and in lieu of real transclusion, I'm linking to Ashok's blog: see "Linking and the Law".
Following this: the problems identified in Governance and Web Architecture are visible here:
- Regulation doesn't match technology
- Regulations conflict because of technology mis-match
- Jurisdiction is local, the Internet is global
The second most serious problem is that standards for what is or isn't OK to do will vary widely across communities to the extent that user created content cannot be reasonably vetted for general distribution.
April 2, 2013
What I thought was interesting was the scope of what the speaker's definition of "Safe" and "Secure", and the mismatch to the technologies and methods being considered. "Safety" included "letting my kids surf the web without coming across pornography or being subject to bullying", while the methods they were talking about were things like site blocking by IP address or routing.
This seems like a oomplete mismatch. If bullying happens because harassers facebook post nasty pictures which they label with the victim's name, this problem cannot be addressed by IP-address blocking. "Looking in the wrong end of the telescope."
I'm not sure there's a single right answer, but we have to define the question correctly.
March 25, 2013
JSON is often used for serializing and transmitting structured data over a network connection. It is commonly used to transmit data between a server and web application, serving as an alternative to XML.
JSON was originally specified by Doug Crockford in RFC 4627, an "Informational" RFC. IETF specifications known as RFCs come in lots of flavors: an "Informational" RFC isn't a standard that has gone through careful review, while a "standards track" RFC is.
An increasing number of other IETF documents want to specify a reference to JSON, and the IETF rules generally require references to other documents that are the same or higher levels of stability. For this reason and a few others, the IETF is starting a JSON working group (mailing list) to update RFC 4627.
The W3C also is developing standards that use JSON and need a stable specification.
Risk of divergence
Unfortunately, there is a possibility of (minor) divergence between the two specifications without coordination, either formally (organizational liaison) or informally, e.g., by making sure there are participants who work in both committees.
There is a formal liaison between IETF and W3C. There is
currently no also a formal liaison between W3C and ECMA (and a mailing list, firstname.lastname@example.org ). There is no formal liaison between TC39/ECMA and IETF.
Having multiple conflicting specifications for JSON would be bad. While some want to avoid the overhead of a formal liaison, there needs to be explicit assignment of responsibility. I'm in favor of a formal liaison as well as informal coordination. I think it makes sense for IETF to specify the "normative" definition of JSON, while ECMA TC-39's ECMAScript 6.0 and W3C specs should all point to the new IETF spec.
JSON vs. XML
JSON is often considered as an alternative to XML as a way of passing language-independent data structures as part of network protocols.
In the IETF, BCP 70 (also known as RFC 3470) "Guidelines for the Use of Extensible Markup Language (XML) within IETF Protocols" gives guidelines for use of XML in network protocols. However, this published in 2003. (I was a co-author with Marshall Rose and Scott Hollenbeck.)
But of course these guidelines don't answer the question many have: When people want to pass data structures between applications in network protocols, do they use XML or JSON and when? What is the rough consensus of the community? Is it a choice? What are the alternatives and considerations? (Fashion? deployment? expressiveness? extensibility?)
This is a critical bit of web architecture that needs attention. The community needs guidelines for understanding the competing benefits and costs of XML vs. JSON. If there's interest, I'd like to see an update to BCP 70 which covers JSON as well as XML.
December 30, 2012
This is the fourth in a series of blog posts about my personal priorities for Web standards and the W3C TAG, as part of the ongoing TAG election.
The Mission of the W3C TAG has three aspects:
- to document and build consensus around principles of Web architecture and to interpret and clarify these principles when necessary;
- to resolve issues involving general Web architecture brought to the TAG; and
- to help coordinate cross-technology architecture developments inside and outside W3C.
Success has been elusive:
- After the publication of Architecture of the World Wide Web in 2004, attempts to update it, extend it, or even clarify it have foundered.
- Issues involving general Web architecture are rarely brought to the TAG, either by Working Group chairs, W3C staff, or the W3C Director, and those issues that have been raised have rarely been dealt with promptly or decisively.
- The TAG's efforts in coordinating cross-technology architectural developments within W3C (XHTML/HTML and RDFa/Microdata) have had mixed results. Coordinating cross-technology architecture developments outside W3C would require far more architectural liaison, primarily with IETF's Internet Architecture Board but also with ECMAScript TC39.
Building consensus around principles of Web architecture
I have long argued that the TAG practice of issuing Findings is not within the TAG charter, and does not build consensus. In the W3C, the issuing of a Recommendation is the stamp of consensus. There may be a few cases where the TAG is so far in advance of the community that achieving sufficient consensus for Recommendation is impossible, but those cases should be extremely rare.
- Recommendation: Review TAG Findings and triage; either (a) update and bring the Finding to Recommendation, (b) obsolete and withdraw, or (c) hand off to a working group or task force.
To build consensus, the TAG's technical focus should match more closely the interest of the Web community.
- Recommendation: Encourage and elect new TAG members with proven leadership skills as well as interest and experience in the architectural topics of most interest to W3C members.
- Recommendation: The TAG should focus its efforts on the "Web of Applications" at the expense of shedding work on the semantic web and pushing ISSUE-57 and related topics to a working group or task force.
Updating AWWW to cover Web applications, Web security and other architectural components of the modern Web is a massive task, and those most qualified to document the architecture are also likely to be inhibited by the overhead and legacy of the TAG.
- Recommendation: Charter a task force or working group to update AWWW.
Resolving issues involving general Web architecture brought to the TAG
To resolve an issue requires addressing it quickly, decisively, and in a way that is accepted by the parties involved. The infamous ISSUE-57 has been unresolved for over five years. The community has, for the most part, moved on.
- Recommendation: encourage Working Group chairs and staff to bring current architectural issues to the TAG.
- Recommendation: drop issues which have not been resolved within a year of being raised.
Coordinate cross-technology architectural developments inside and outside W3C
Within W3C, one contentious set of issues involve differing perspectives on the role of standards.
- Recommendation: The TAG should define the W3C's perspective on the Irreconcilable Differences I've identified as disagreements on the role of standards.
For coordination with standards outside of W3C:
- Recommendation: The TAG should meet at least annually with the IETF IAB, review their documents, and ask the IAB to review relevant TAG documents. The TAG should periodically review the status of liaison with other standards groups, most notably ECMA TC39.
On the current TAG election
An influx of new enthusiastic voices to the TAG may well help bring the TAG to more productivity than it's had in the past years, so I am reluctant to discourage those who have newly volunteered to participate, even though their prior interaction with the TAG has been minimal or (in most cases) non-existent. I agree the TAG needs reform, but the platforms offered have not specifically addressed the roadblocks to the TAG accomplishing its Mission.
In these blog posts, I've offered some insights into my personal perspectives and priorities, and recommended concrete steps the TAG could take.
If you're participating in W3C:
- Review carefully the current output and priorities of the TAG and give feedback.
- When voting, consider the record of leadership and thinking, as well as expertise and platform.
- Hold elected TAG members accountable for campaign promises made, and their commitment to participate fully in the TAG.
Being on the TAG is an honor and a responsibility I take seriously. Good luck to all.
December 29, 2012
This is the third of a series of posts about my personal priorities for Web standards, and the relationship to the W3C TAG.
Internet Applications = Web Applications
For better or worse, the Web is becoming the universal Internet application platform. Traditionally, the Web was considered just one of many Internet applications. But the rise of Web applications and the enhancements of the Web platform to accommodate them (HyBi, RTCWeb, SysApps) have further blurred the line between Web and non-Web.
Correspondingly, the line between IETF and W3C, always somewhat fuzzy, has further blurred, and made difficult the assignment of responsibility for developing standards, interoperability testing, performance measurement and other aspects.
Unfortunately, while there is some cooperation in a few areas, coordination over application standards between IETF and W3C is poor, even for the standards that are central to the existing web: HTTP, URL/URI/IRI, MIME, encodings.
W3C TAG and IETF coordination
One of the primary aspects of the TAG mission is to coordinate with other standards organizations at an architectural level. In practice, the few efforts the TAG has made have been only narrowly successful.
An overall framework for how the Web is becoming a universal Internet application platform is missing from AWWW. The outline of architectural topics the TAG did generate was a bit of a mish-mash, and then was not followed up.
The current TAG document Best Practices for Fragment Identifiers and Media Type Definitions, is narrow; the first public working draft was too late to affect the primary IETF document that should have referenced it, and is likely to not be read by those to whom it is directed.
There cannot be a separate "architecture of the Internet" and "architecture of the Web". The TAG should be coordinating more closely with the IETF Internet Architecture Board and applications area directorate.
This is the second in a series of posts about my personal priorities for the W3C Technical Architecture Group.
Computer security is a complex topic, and it is easy to get lost in the detailed accounts of threats and counter-measures. It is hard to get to the general architectural principles. But fundamentally, computer security can be thought of as an arms race: new threats are continually being invented, and counter-measures come along eventually to counter the threats. In the battle between threats and defense of Internet and Web systems, my fear is that the "bad guys" (those who threaten the value of the shared Internet and Web) are winning. My reasoning is simple: as the Internet and the Web become more central to society, the value of attacks on Internet infrastructure and users increases, attracting organized crime and threats of cyber-warfare.
Further, most reasoning about computer security is "anti-architectural": the exploits of security threats cut across the traditional means of architecting scalable systems—modularity, layering, information hiding. In the Web, many security threats depend on unanticipated information flows through the layer boundaries. (Consider the recently discovered "CRIME" exploit.) Traditional computer security analysis consists of analyzing the attack surface of a system to discover the security threats and provide for mitigation of those threats.
New Features Mean New Threats
Much of the standards community is focused on inventing and standardizing new features. Because security threats are often based on unanticipated consequences of minor details of the use of new features, security analysis cannot easily be completed early in the development process. As new features are added to the Web platform, more ways to attack the web are created. Although the focus of the computer security community is not on standards, we cannot continue to add new features to the Web platform without sufficient regard to security, or to treat security as an implementation issue.
Governance and Security
In many ways, every area of governance is also an area where violation of the governance objectives has increasing value to an attacker. Even without the addition of new features, deployment of existing features in new social and economic applications grows the attack surface. While traditional security analysis was primarily focused on access control, the growth of social networking and novel features increases the ways in which the Web can be misused.
The W3C TAG and Security
The original architecture of the Web did not account for security, and the W3C TAG has so far had insufficient expertise and energy to focus on security. While individual security issues may be best addressed in working groups or outside the W3C, the architecture of the Web also needs a security architecture, which gives a better model for trust, authentication, certificates, confidentiality, and other security properties.
I promised I would write more about my personal priorities for W3C and the W3C TAG in a series of posts. This is the first. Please note that, as usual, these are my personal opinions. Comments, discussion, disagreements welcome.
A large and growing percentage of the world depends on the Internet as a critical shared resource for commerce, communication, and community. The primary value of the Internet is that it is common: there is one Internet, one Web, and everyone on the planet can communicate with everyone else. But whenever there is a shared resource, opportunities for conflict arise—different individuals, groups, companies, nations, want different things and act in ways that threaten this primary value. There are endless tussles in cyberspace, including conflicts over economics, social policy, technology, and intellectual property. While some of the conflicts are related to "whose technology wins," many are related to social policy, e.g., whether Internet use can be anonymous, private, promote or allow or censor prohibited speech, protect or allow use of copyrighted material.
Shared resources in conflict, unregulated, are ultimately unsustainable. The choices for sustainability are between voluntary community action and enforced government action; if community action fails, governments may step in; but government action is often slow to move and adapt to changes.
As the recent kerfuffle over ITU vs. "multi-stakeholder" governance of the Internet shows, increased Internet regulation is looming. If the Internet community does not govern itself or provide modes of governance, varying national regulations will be imposed, which will threaten the economic and social value of a common Internet. Resolving conflict between the stakeholders will require direct attention and dedicated resources.
Governance and W3C
Standards and community organizations are a logical venue for addressing most of Internet governance conflicts. This is primarily because "code is law": the technical functioning of the Internet determines how governance can work, and separating governance from technology is usually impossible. Further, the community that gathers at IETF and W3C (whether members or not), are the most affected.
I think W3C needs increased effort and collaboration with ISOC and others to bring "governance" and "Web architecture for governance" to the forefront.
Governance and the W3C TAG
The recent TAG first public working draft, "Publishing and Linking on the Web" is an initial foray of the W3C TAG in this space. While some may argue that this work exceeds the charter of the TAG, I think it's valuable work that currently has no other venue, and should continue in the TAG.