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In case anyone's been wondering why a hefty plurality if not an outright majority of the stories pushed over the weekend and the first couple days of the week came from yours truly, it's because I hopped on my cavalry bear, rode all over the country, and beat all the Editors except martyb (who I saved for last and only had to threaten into submission) upside the head with a double-barrel chainsaw.

Or it's because I saw there was pretty much nothing except partisan hack jobs and bloody stupid garbage that I sincerely hope the Eds never publish in the submission queue and quickly subbed everything remotely interesting that I found in my feed reader.

Believe whichever amuses you the most.

(This is the fifth of many promised articles which explain an idea in isolation. It is hoped that ideas may be adapted, linked together and implemented.)

What are the properties usually associated with Internet Protocol 6? Multi-cast? A huge address space? A cleaner implementation with more packet throughput? Whatever.

Multi-Cast

Internet Protocol 4 addresses from 224.0.0.0 to 239.255.255.255 are for multi-cast, as defined in RFC1112. Unfortunately, multi-cast is incompatible with TCP, so that's 2^26 Internet Protocol 4 addresses and 2^120 Internet Protocol 6 addresses which don't work with YouTube or QuickTime.

Address Space

Internet Protocol 6 has 128 bit addresses. That's more addresses than atoms in the visible universe. However, there are edge cases where that's insufficient. Internet Protocol 4 has 32 bit addresses (by default) and that was considered vast when it was devised. That was especially true when total human population was less than 2^32 people. Superficially, it was possible to give every person a network address.

Several address extension schemes have been devised. The best is RFC1365 which uses option blocks to optionally extend source and destination fields in a manner which is downwardly compatible. So, what size is an Internet Protocol 4 address? 32 or more bits, as defined by RFC1365.

Header Size

Internet Protocol 4 is often described as having a 20 byte (or larger) header while Internet Protocol 6 is often described as having a header which is exactly 40 bytes. This is false. IPv6 has option blocks just like IPv4 and therefore both have variable length headers. The difference is that IPv6 headers are usually 20 bytes larger.

Packet Size

IPv4 typically supports a PMTU of 4KB or more. Admittedly, there are no guarantees but Ethernet without packet fragmentation provides about 1500 bytes. With PPPoA or PPPoE over AAL5 over ATM, 9KB payloads only fragment over the last hop. This is ideal for video delivery. IPv6 only guarantees 1280 bytes. How common is this? Numerous variants of micro-controller networking only support 1280 buffers. This is especially true for IPv6 over IEEE802.15.4 implementations. This is especially bad for video.

Packet Fragmentation

IPv6 has no packet fragmentation. IPv6 packets which exceed MTU always disappear.

Packet Throughput

Compared to IPv4, IPv6 generally has longer headers, longer addresses and shorter payloads. On this basis, how would you expect packet throughput of IPv6 to match or exceed IPv4?

Summary

The introduction of IPv6 provides no particular benefit to end-users. IPv6 is detrimental payload size and this is particularly detrimental to video delivery.

(This is the fourth of many promised articles which explain an idea in isolation. It is hoped that ideas may be adapted, linked together and implemented.)

Via a fairly arbitrary process, I've got to a stage of explaining pragmatic problems with naming stuff in a computer.

Many naming schemes require a name resolution process. The process used by DNS is overly complicated. Although it would be easy to poke fun at systemd's repeated failures in this field, djbdns has been attacked with cache poisoning and steps have been taken to mitigate timing attacks by implementing UDP port randomization. An observation which could be made from djb's similar syncookies is that it is insufficient to implement baseline TCP or DNS because the Internet has become too hostile.

I investigated the implementation of Project Xanadu transclusion using DNS. The use of UDP to assemble small fragments of data in a fault-tolerant manner has obvious appeal. DNS's maximum fragment length of 255 bytes is unfortunate but can be overcome. However, popular DNS implementations, such as BIND are don't cache unknown response types. This means A records, TXT records or suchlike would have to be overloaded. Ideally, this should be handled carefully due to compressed encoding workarounds and record permutation compatible with the POSIX legacy singleton record interface.

It is possible to ignore these pleasantries and transport raw data as A records but this has two problems. Firstly, to obtain raw records, the local resolving has to be located without the benefit of the host's DHCP or suchlike. Secondly, administrators baulk at volume of data transported via their DNS infrastructure - and rightly so because this doesn't degrade gracefully. One user's browsing would be sufficient to cause intermittant or sustained host resolution failure within a local network. Video streaming over DNS is feasible to implement but would be anti-social to anyone sharing upstream infrastructure.

An erroneous assumption made by Project Xanadu is that multi-media can be handled almost as a corollary of handling text. I presume the logic is that multi-media is traditionally serialized and therefore can be subjected to similar constraints as paragraphs of text. However, I believe this is backward. If multi-media can be handled as three dimensional data (horizontal, vertical, frame number) or two dimensional data (audio channel, position) then one dimensional data (text) is the corollary.

So, an outline of requirements is as follows:-

• Simplified DNS is desirable.
• Traffic priority should be lower than legacy DNS implementation.
• Should allow server fail-over.
• Should allow 8 bit clean queries.
• Should allow 8 bit clean responses.
• Should have a compact representation.
• Should provide authentication.
• Should provide encryption.
• Should provide server delegation.
• Should provide a correct implementation of cache invalidation.
• Data should be served as UDP or similar.
• Should be optimized for small payloads but allow arbitrary volumes of data.
• Should permit addressing of one frame of video.
• If possible, should permit addressing of a range of video frames.

Although this looks like a system favoring a hierarchy of servers within one domain of trust, it remains possible to implement a federation of server hierarchies.

(This is the third of many promised articles which explain an idea in isolation. It is hoped that ideas may be adapted, linked together and implemented.)

How did we get to the current state of desktop computing and why is the future so uncertain? How did this veer so quickly into one of the deep topics of philosophy?

When Xerox PARC was founded in 1970, object programming languages, arbitrary bitmap displays, vector graphic storage formats, laser printing and ubiquitous desktop computer networking had yet to be developed. The development of a kid-safe computer which was no larger or heavier than a pad of paper was a futuristic dream. Nowadays, it seems laughably quaint. Unfortunately, continuous reference to paper has left us in a fascist dystopia of bureaucracy.

Our fundamental unit of information is not a bit, a factoid or a qubit. Our fundamental unit of information is a document, a form, a search, a sale or a recording. Unfortunately, with technology such as voice activated search, these units are often intertwined. In the broader case, this information is often used against a people who can or cannot be easily herded.

One future direction for technology is the full implementation of Ted Nelson's Project Xanadu. Ted Nelson is extremely irked by the current state of hypertext (a word he invented or popularized). However, his vision for orbiting satellites caching data paid with micropayments (another word he invented or popularized) remains outlandish after more than 40 years.

However, it is becoming less outlandish and is within the realm of tractable. Specifically, HTTP/1.0, as defined in RFC1945 reserved response code 402 for payment. When this was defined in May 1996, it was seen as a nod to our forefathers but with crypto-currency worth US$100 billion, implementation is a question which is being asked with increasing frequency.

It may be that Ted Nelson is fully vindicated and that the transition to DOI style tumblers and micropayments required a diversion via Zooko's triangle (however badly implemented). Prior to HTML and HTTP, hypertext was a knot of style, presentation, interface, content and transport. Systems such as Microsoft Help and AmigaGuide typically stored multiple documents in one annotated text file. HTTP/0.9 decisively cleaved storage, transport and presentation. However, it left a foreseeable trail of a trillion broken hyperlinks and an economic model which ate broadcast and print advertising.

If you've been following closely, you'll see that there are multiple possible formats for a reference to a resource. Typical formats include:-

• foo://host.domain.tld/path/to/res.ext - URL.
• bar:012345678abcdef - Hash of content.
• baz:9.17.2.6.22-24 - Tumbler range.

Each has limitations. All function within a string namespace, although, historically, inter-operability usually fails. Ignoring this, questions remain. What do we wish to reference? How do we wish to reference it? (Source. Destination. Quantity. Frequency.)

There are further complications with references and I intend to describe them next.

(This is the second of many promised articles which explain an idea in isolation. It is hoped that ideas may be adapted, linked together and implemented.)

Many of the limitations of computers occur because we have a poor simulation of paper popularized by a photocopying company.

However, there is another way. For this, I choose something which approximates a URL as a building block of information.

All problems in computer science can be solved by another level of indirection. -- Butler Lampson, Xerox.

By chosing a pointer in a namespace, we may reference legacy data (documents, multi-media files) in addition to data in the structure of our choice. If a URL, URN or URI was sufficient for this task then no further work would be required. However, a different approach is strictly necessary because:-

There are only two hard things in computer science: cache invalidation and naming things. -- Phil Karlton, Netscape.

In the current form, URLs, cookies and caching interact badly. For example, HTML requests made with different cookies cannot be shared among users. Whereas, image requests made with different cookies are handled as if the cookies were absent. This situation requires cache authors to implement a heuristic to ensure that most websites are compatible with one cache. Whereas, authors of popular websites implement a heuristic to ensure that most caches are compatible with their websites. The lack of fundamentals (no formal specification for URL caching) requires multiple parties to maintain complicated models. This is required so that a grammatically correct request for grammatically correct content behaves as expected.

A general problem with naming is Zooko's Triangle: Distributed, Secure, Human-Readable: Choose Two. However, even this would be an improvement. URLs incorporating DNS are not distributed. (DNS *servers* are distributed but a DNS namespace straddles one domain of trust.) URLs with or without SSL or TLS are not secure. 95% of users cannot read URLs.

Given an unconstrained choice, something like a Magnet URI would seem beneficial. However, this relies upon a chosen cryptographic hash function being a trapdoor function. If a practical quantum computer cracks the chosen trapdoor function then we have names which are neither secure nor readable. On the basis that security within a name cannot be guarateed, it may be preferable to err towards readable names and seek security elsewhere.

There are further complications with names and I intend to describe them next.

(This is the first of many promised articles which explain an idea in isolation. It is hoped that ideas may be adapted, linked together and implemented.)

Someone from my makerspace said "We're living in a post-Xerox world." and he didn't mean Xerox's business of photocopiers.

The original objectives of Xerox PARC are in widespread use. That includes object programming languages, arbitrary bitmap displays, vector graphic storage formats, laser printing, ubiquitous desktop computer networking and - most notably - ruggedized, kid-safe computers which are no larger or heavier than a pad of paper.

He believes that we're in a malaise because we've reached a widely known goal and there is no agreed continuation. Actually, he believes the problem is more fundamental. Collectively, we don't know that there was a set of ideas popularized by one organization nor do we know that we attained it.

I believe that we have a different problem. We've implemented digital paper rather than digital computing. This would be a problem if it stayed in a computer but it often spills onto paper too. A word-processor and rapid printing is contrary to a paperless workflow. Most significantly, it has continued the trend of increasing bureaucracy and forms. Even in the 18th century, people complained that there were too many forms. Now we have forms on paper, in HTML, PDF, apps and elsewhere.

This is tedious. It costs time and money. There is the obvious cost of time spent completing a form and time spent by administrators to process a form. Many types of fraud can be achieved merely by completing forms. As an example, a dental fraud cost UK taxpayers £1.4 million (US$2 million). It was achieved by completing about 30 forms per day describing fictious dental treatment.

Bureaucracy is organized around institional memory. This may be quipu storage, filing cabinets, file servers or databases. Bureaucrats perform ingress and egress filtering. Both may be infuriating. Ingress filtering should ensure that institional memory is accurate but this rarely occurs when the cost of errors is externalized. For example, when hundreds of large companies have read/write access to credit checks, the majority of credit reports are wrong. Egress filtering should restrict disclosure of sensitive information but, again, costs are externalized. Obtaining any meaningful change of state may be difficult. Ensuring an accurate round-trip of data may be impossible. Likewise for any inter-organizational change of state.

Block-chain enthusiasts claim that smart-contracts will significantly reduce these problems. It could make inter-organizatioal state atomic. However, unwinding bad states may require an individual with the skills of a lawyer and a programmer. Furthermore, the reduced friction of transactions could make state changes more frequent. Essentially, by Jevons paradox, this encourages more bureaucracy. Meanwhile, the interface between person and bureaucracy may become increasingly quixotic.

Forms continue to proliferate without satisfactory user testing and each form remains an oblique signal for a bureaucracy to change state. That's increasingly irrelevant when nation-states are falling apart and corporations are increasingly untrustworthy. Indeed, while peons are completing each other's forms and contact each other in telephone call centers, our overlords collect data in bulk and transform it into structured data. The most benign example is marketing analytics for the purpose finding the local maxima of a business model. Another example is an opt-out, keyword aggregating marketplace which skims value from millions of parties. This is commonly called a search engine. Then there is the fascist, totalitarian panopticon of signals intelligence which treats every citizen as an enemy.

However, there is another way. It requires a more suitable building block of data. I intend to describe this next.

This article has almost nothing to do with a promised series of articles. Instead, this is a continuation of motor control using audio amplifiers.

I previously discovered that a commonly available PAM8403 stereo audio amplifier board is sufficient to control two small motors. This is possible because the amplifier is intended to drive speakers with 4 Ohm or 8 Ohm windings. A speaker is a special case of linear motor and many small motors similarly have 4 Ohm or 8 Ohm windings.

The major advantage of this scheme is that *any* headphone output may be sufficient to control two motors. This includes pre-recorded sound or any programming language which can play sounds. That includes programming languages aimed at kids, such as Scratch and Squeak.

In some regards, a PAM8403 is an overkill for hacking. Regardless, it has advantages over an H-Bridge. For example, a linear amplifier allows forwards and backwards operation of two motors at variable speed. The major catch is that audio amplifiers expect an RTZ [Return To Zero] signal and therefore sending a continuous positive or negative signal fails to have any sustained impact. This can be overcome by sending a square wave of arbitrary amplitude and arbitrary duty cycle. A quirk of this encoding is that the square wave frequency isn't hugely important. We'll be using that property next.

A member of my makerspace asked if it was possible to control four motors using two audio channels. (Specifically, he's obsessed with quadcopters, drones and suchlike.) After some false starts, I found that an audio channel can be partially split into two by using an analog low-pass filter.

In this arrangement, the majority of an audio channel's amplitude is allocated to a low frequency square wave. This is directed to one pair of motors and allows the pair to be driven at almost maximum speed. The remainder of the audio channel's amplitude is allocated to a high frequency square wave which may have a complimentary or opposing bias. This is directed to one motor of the pair and provides stabilization of the platform in one axis.

For each audio channel, the audio filter consists of one resistor in series followed by one capacitor to ground. The product of the resistor and capacitor in the RC network determines the resonant frequency of the filter in radians per second. (Adjust by 2π to obtain cycles per second.) Optionally, use multiple RC networks in series to increase signal discrimination. However, for this application, it isn't particularly important.

Worked figures are as follows. Low frequency signal is 440Hz. Cut-off frequency is low frequency times four. High frequency signal is cut-off frequency times four. Resistors should be 470 Ohms. Capacitors should be 220pF.

I assumed that two stereo amplifiers would be required. By chance, another member of my makerspace was making an enclosure for stereo speakers and re-chargable batteries. The audio amplifier is a TDA7379 which is a quadraphonic amplifier which can be ganged into stereophonic. As a quadraphonic amplifier, it provides 13W per channel. I haven't gone through figures in detail but that should be sufficient to lift a computer, gyroscope and batteries. This is an extremely dangerous project but it is also shockingly accessible.

Looks like we let the story queue run completely dry last night for about 3.5 hours. Feel free to give the Eds some good-natured ribbing over it here.

I have difficulty collaborating with other people. It may be that I'm a cantankerous curmudgeon but I suspect this is (also) a wider problem.

I write software. I dabble with analog and digital electronics. I do computer system adminstration and database administration. I prefer to write in C (for speed) and Perl (because the interpreter is everywhere). I greatly prefer to avoid proprietary environments. Although I've been described as being to the left of Richard Stallman, my interest in open licences comes primarily from not being able to use my own work. (Others take a much more hard-line approach and refuse outright to work on anything which won't be GNU Public Licence.)

I'm willing to work almost anywhere in the world. I'm willing to work with micro-controllers, super-computers, Lisp, PHP, bash, Linux, BSD, ATM, SPI, I2C, CANBus and numerous other concepts. I prefer to work with content versioning (any is better than none) and repeatable processes. However, I'm willing to work in an environment which scores 4 out of 12 on the Joel Test.

I have difficulty getting enthused about:-

• "Apps" where Apple or Google take 30%. This isn't a good deal for me or many clients.
• node.js or other JavaScript - especially in conjunction with robot control.
• C++, C#, Objective C, D or any other derivative of C.
• Anything over radio - especially IEEE802.15.4
• Block-chain systems in their current form.
• Facial recognition.
• Neural networks.
• "User experience."
• "Cloud."

I'm more enthused about FPGA and GPU programming but I like to have an abundance of hot-spares and, for me, that significantly increases a barrier to entry. This hardware also makes me edgy about being able to use my own work in the long-term.

Within these parameters, I'd like to describe some failed explorations with other techies. Without exception, I first encountered these techies at my local makerspace.

One techie is a huge fan of Mark Tilden, inventor of the RoboSapien and numerous other commerialized robots. Mark Tilden has an impeccable pedigee and has been featured in Wired Magazine and suchlike over 20 years or more. Mark Tilden espouses a low-power analog approximation of neurons with the intention of the neurons forming a combinatorial explosion of resonant states. When implemented correctly, motor back-EMF influences the neurons and therefore a robot blindly adjusts its (resonant) walking gait in response to terrain.

Anyhow, my friend was impressed that I'd used an operational-amplifier as an analog integrator connected to a VCO [Voltage Contrlled Oscillator] for the purpose of controlling servo motors without a micro-controller. My friend hoped that we'd be able to make a combo robot which, as a corollary, would perform a superset of 3D printing functionality without using stepper motors or servo motors. This is fairly ambitious but it would be worthwhile to investigate feasibility.

To complicate matters, I'm in a situation where modest financial success in this (or other) venture would gain my full-time attention. Whereas, he's currently receiving workman's compensation due to an incident at his electro-mechnical engineering job. So, I have every reason to commercialize our efforts and he has exactly the opposite motive.

There's also the scope of robot projects. They tend to be fairly open-ended and this in itself is cause for project failure. Therefore, I tried to nudge my friend into a project with a well-defined scope, such as high-fidelity audio reproduction. It is from attempts to make this situation work that I found that PAM8403 audio amplifiers were ideally suited to control motors. However, this discovery and further discoveries around it have not enthused my friend. (Note that the specification, as it exists, was to make an analog robot and avoid the use of stepper motors or servo motors. Admittedly, this fails to incorporate back-EMF but it is otherwise satisfactory.)

He's had personal problems which include his cheating Goth girlfriend dumping him and giving away his cat. He's also got his employer asking him to come back to work. Understandably, our collaboration has stalled.

An ex-colleague wants to collaborate in different projects. So far, we've had one success and one failure. The success contributed to a mutual ex-colleague's first Oscar nomination. The failure (his PHP, my MySQL) completely failed to mesh but led to a customized aggregator responsible for many articles on SoylentNews.

He's currently proposing an ambiguous deal which appears to be a skill-swap where we retain full rights on projects that we initiate. However, many of his projects involve tinkering with ADC and/or LCD. This would have been highly lucrative in the 1980s. Nowadays, it is somewhere between economizing and procrastinating. He previously worked on 100 Volt a monophonic valve amplifier but that was about three years ago and he never bothered to commercialize it.

Prior to this, I worked with friends on LEDs for an expanding market. We worked through the tipping point where the NFL and Formula 1 switched to LEDs. Two years ago, we were four years behind the market leader. Since then, we have completely failed to sell any LEDs to anyone. The majority have been using the venture for resumé padding and I've been out-voted on features even though I'm the only person who worked in the industry and worked with customers on a daily basis. After verbally being offered less than half of an equal share in my own venture, I haven't seen one of the active co-founders for 10 months. It would be reasonable to say that people are avoiding me. I find this bizarre.

Regardless, my task was to make a secure controller. The primary resumé padder wanted something which looked like an Apple TV. (This is for an industrial controller which may be exposed to 100% humidity and is required to meet ISO 13850.) I tried various options while being resource starved. I found that the software specification has yet to be achieved on a modern system. I found that the hardware specification is very difficult without an obscene budget. I also found that development on ARM has been difficult until relatively recently. The most accessible ARM system, a Raspberry Pi, didn't gain hardware floating point support under Linux until May 2016. Parties with successful projects (mostly phones) like these high barriers to entry. (How did Cobalt Networks launch successful RISC products in 1998? By using MIPS rather than ARM - and then switching to x86.)

In recent discussion about Raspberry Pi usage, you'll see how I've been influenced over the last two years or so about long-term support, hardware and packaging, micro-controller code density and other matters. I've also added options for documentation and training. However, without aligned collaborators or sensible resources, I'm not progressing. I suspect others are in diverse but analogous situations. Do you want to collaborate?

The fine pieces of shit over at Rolling Stone recently interviewed Billy Joel:

Critics used to give you a hard time. But it seems like in the past few years you've become cool.
Look, man, Trump is president, so all kinds of weird shit can happen.

What do you make of that?
I'm still flabbergasted. I try to stay out of politics. I am a private citizen and I have a right to believe in my own political point of view, but I try not to get up on a soapbox and tell people how to think. I've been to shows where people start haranguing the audience about what's going on politically and I'm thinking, "You know, this isn't why I came here." As a matter of fact, one of the biggest cheers of the night comes when we do "Piano Man" and I sing, "They know that it's me that they're coming to see to forget about life for a while," and the audience lets out this huge "ahhhh" and I say, "OK, yeah, don't forget that." We're more like court jesters than court philosophers.

Normally I wouldn't even pay attention to some celebrity spouting off on politics (Because who gives a damn?) but Joel absolutely nails what a whole lot of folks are thinking on the matter. Tip of the hat to the Piano Man for keeping it classy.