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>>> 2021-06-12 ieee 1394 for grilling

To begin with, a reader emailed me an objection to my claim that Smalltalk has never been used for anything. They worked at an investment bank you have heard of where Smalltalk was used for trading and back office systems, apparently at some scale. This stirred a memory in me---in general the financial industry was (and to some extent is) surprisingly interested in "cutting edge" computer science, and I think a lot of the technologies that came out of first-wave artificial intelligence work really did find use in trading especially. I'd be curious to hear more about this from anyone who worked in those environments, as I know little about finance industry technology (despite my interest in their weird phones). Also, I am avoiding naming this reader out of respect for their privacy and because I neglected to ask them if it's okay to do so before going to publish this. So if you email me interesting facts, maybe do me a favor and mention whether or not you mind if I publish them. I'm bad at asking.

And now for something completely different.

Years ago, at a now-shuttered Smith's grocery store in my old home of Socorro, New Mexico, I did a dramatic double-take at a clearance rack full of Firewire. This Firewire was basically a steel cable used like a skewer but, well, floppy. The name got a chuckle out of me and this incident somehow still pops into my mind every time I think about one of my "favorite" interconnects: IEEE 1394.

IEEE 1394 was developed as a fast serial bus suitable for use with both storage devices and multimedia devices. It was heavily promoted by Apple (its original creator) and present on most Apple products from around 2000 to the switch to Thunderbolt, although its popularity had decidedly waned by the time Thunderbolt repeated its mistakes. FireWire was never as successful as USB for general-purposes usage. There are various reasons for this, but perhaps the biggest is that FireWire was just plain weird.

What's it called?

IEEE 1394 was developed by several groups in collaboration, but it was conceived and championed by Apple. Apple refers to it by the name FireWire, and so do most humans, but Apple held a trademark on that name. While Apple made arrangements to license the trademark to a trade association for use on other implementations in 2002, long after that most PC manufacturers continued to use the term IEEE 1394 instead. I am not clear on whether or not this was simple aversion to using a name which was strongly associated with a competitor or if these implementations were somehow not blessed by the 1394 Trade Association.

In any case, you will probably find the terms FireWire and IEEE 1394 used with roughly equal frequency. For further confusion, Sony uses the term i.LINK to refer to IEEE 1394 on their older products including cameras and laptops. Wikipedia says that TI also refers to it as Lynx, but I haven't seen that name personally and cursory internet research doesn't turn up a whole lot either.

The lack of a single, consistent brand identity for FireWire might be seen as its first major mistake. My recollection from FireWire's heyday is that there were indeed people who did not realize that FireWire devices could be used with non-Apple computers, even though "IEEE 1394" interfaces were ubiquitous on PCs at the time. I think this must have negatively impacted sales of FireWire peripherals, because by the time I was dealing with this stuff the only storage peripherals being sold with FireWire were being marketed exclusively to Apple users by historically Apple-associated brands like Macally and LaCie.

What does it look like?

Further contributing to compatibility anxiety was the variety of physical connectors in use. The major FireWire connectors in use were (most commonly) called Alpha, Sony, and Beta. The difference between Alpha and Beta was one of speed, as Alpha was designed for FireWire 400 (400Mbps) and Beta for FireWire 800 (800Mbps). Even this change, though, required the use of so-called "Bilingual" cables with Alpha on one end and Beta on the other.

The Sony standard, which worked only with FireWire 400, was smaller and so popular on mobile or otherwise low-profile devices. A number of laptops also used this smaller connector for reasons I'm not completely clear on (the Alpha connector is not significantly larger than USB).

The result was that practical use of FireWire frequently required adapters or asymmetric cables, even more so than USB (where the device connector was inconsistent) since both ends had a degree of inconsistency involved. The hassle was minor but surely didn't help.

Just to make things more fun, FireWire could be transported over twisted pair (UTP) and efforts were made towards FireWire over single mode fiber. I'm not aware of any significant use of these, but the idea of running FireWire over UTP will become significant later on.

Is it cooler than USB?

Unlike USB and other contemporary peripheral interconnects, FireWire had complex support for management and configuration of the bus. Unlike USB which was 1:1 computer to device, FireWire supported arbitrary groups of up to 63 devices in a tree. While there is a "root node" with some centralized responsibility in the operation of the bus, any device can send data directly to any other device without a copy operation at the root node.

This meant that FireWire was almost more a network protocol than a mere peripheral interconnect. In fact, it was possible to transport Ethernet frames over FireWire and thus use it as an IP network technology, although this wasn't especially common. Further supporting network usage, FireWire supported basic traffic engineering in the form of dedicated bandwidth for certain data streams. This was referred to as isochronous mode, and its ability to guarantee a portion of the bus to real-time applications is reflective of one of FireWire's major strengths (suitability for multimedia) and reminds me of just how uncommon this is in common computer systems, which makes me sad.

Despite the common perception in the computing industry that opportunistic traffic management is better^wmore fun^w^weasier to implement, FireWire's allocated bandwidth capability turned out to be one of its most important features, as it fit a particular but important niche: camcorders.

The handheld camcorders of the early 2000s mostly used DV (digital video), which recorded a digital stream onto a magnetic tape (inexpensive random-access storage was not sufficiently durable or compact at the time). In order to transfer a video to a computer, the tape was played back and the contents of the tape sent directly back to the computer, which recorded it. USB proved incapable of meeting the task.

It's not quite as simple as USB being too slow; USB2.0 could meet the data rate requirements. The problem is that USB (until USB 3.0) was polling-based, and so reliable transfer of digital video from a tape relied on the computer polling sufficiently frequently. If it didn't---say because the user was running another program during the transfer---the video would be corrupted. It turns out that, for moving digital media at original quality, allocated bandwidth matters.

Note that FireWire is effectively acting as a packetized video transport in this scenario, just with some extra support for a control channel. This is very similar to later video technologies such as HDMI.

Did the interesting features become a security problem?

The more complicated something is, the more likely it is that someone will use it to steal your credit card information. FireWire is no exception. Part of FireWire's performance advantage was its support for DMA, in which a FireWire device can read or write information directly from a computer's memory. This was a useful performance optimization, especially for high-speed data transfer, because it avoided the need for extra copies out of a buffer.

The problem is that memory is full of all kinds of things that probably shouldn't be shared with every peripheral. FireWire was introduced before DMA was widely seen as a security concern, and well before memory management units that provided security protections on DMA. On many real FireWire devices, access to physical memory was completely unrestricted. Every FireWire device was (potentially) a memory collection device.

What happened to FireWire?

Consumer adoption was always poor outside of certain niche areas such as the DV video transfer use case. I suspect that a good portion of the issue was the higher cost of FireWire controllers (due to their higher complexity), which discouraged FireWire in low-cost peripherals and cemented USB as a more, eh, universal solution. Consumer perceptions of FireWire as being more complex than USB and somewhat Apple specific were likely an additional factor.

That said, the final nail in FireWire's coffin was probably a dispute between Apple and other vendors related to licensing costs. FireWire is protected by a substantial patent portfolio, and in 2002 Apple announced a substantial $1-per-port licensing fee for use of the technology. Although the fee was later reduced, it was a fiasco that took much of the wind out of FireWire's sails, particularly since some major partners on FireWire technology (including Intel) saw it as a betrayal of previous agreements and ended their active promotion of FireWire.

In summation, FireWire seems to have fallen victim to excessive complexity, costly implementation, and licensing issues. Sound familiar? That's right, there's more commonality between FireWire and ThunderBolt than just the name.

While Apple stopped supporting FireWire some years ago, it continues to see a few applications. IEEE 1394 was extended into embedded and industrial buses and is used in the aerospace industry. It also continues to have some use in industrial automation and robotics, where it's used as a combined transport for video and control with machine vision cameras. That said, development of the FireWire technology has basically stopped, and it's likely these uses will fade away in the coming years.

Last of all, I have to mention that US cable boxes used to be required to provide FireWire ports. The reason relates to the conflict of cable providers and cable regulators in the United States, which will be its own post one day.

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>>> 2021-06-07 building the first guis

The modern GUI, as we understand it, can be attributed almost entirely to the work of Douglas Engelbart.

Engelbart

In fact, it is rather surprising to me that so much can be attributed to one person. I have said before that the technology industry moved so quickly that nearly every significant innovation can be attributed to multiple, parallel efforts. In fact this is probably true of the GUI, but any parallel efforts have been deeply forgotten in comparison to Engelbart's pioneering work.

In 1968, Engelbart presented to a conference a demonstration of a project he had built while at SRI. Generally based on Vannevar Bush's [1] conceptual design for the "memex," Engelbart's effort put together nearly all of the major aspects of a modern GUI system. There was a mouse, there were windows, buttons, hyperlinks, menus, everything you could want. The GUI, to a remarkable degree, was just invented all at once.

Of course Engelbart was not precognizant. He made a number of missteps, many of which would be repeated by the XPARC work on the Alto which was closely based on Engelbart's demonstration. Most amusingly, Engelbart found it unlikely that computer users would want to use a mouse with one hand when the keyboard requires both. As a solution he proposed (and used) a one-handed, chord-based keyboard. Despite the best efforts of many dweebs, one handed text entry has never caught on [2].

More profoundly, though, Engelbart failed to anticipate the complete lack of interest in actually implementing the concepts he demonstrated. Despite the amazing impact of his demonstration on the audience, the technology was complex and difficult to build, and bore little resemblance to the text-mode, command-oriented environment which was the respected norm in business computing.

Engelbart invented the modern GUI in 1968. It would not be available on the market until 1981.

From our comfortable position today it is hard to imagine how this could be. GUIs seem to be the obvious progression in computer interfaces. Yet, during Engelbart's work his vision was regarded as largely academic, not practical. GUIs as a concept were closely tied to cybernetics and artificial intelligence, fields which attracted a great deal of graduate students but very few actual users. The GUI was cool, it was interesting, but it was not practical.

This situation is perhaps most exemplified by Smalltalk. Smalltalk was developed at XPARC (that's the Xerox Palo Alto Research Center) as a teaching language, and was best known for being an early object-oriented language and for its frequent implementation in highly GUI-centric virtual machines. Major implementations like Squeak couple Smalltalk with graphical development and debugging environments which are surprisingly cutting edge, and yet completely unused.

You see, Smalltalk, despite its innovations, has basically always been constrained to academia. Most CS students are exposed to Smalltalk at some point (probably in a programming language theory course), but no one actually uses it for anything. The situation was largely the same for all graphical environments through the course of the '70s and to a good degree into the '80s.

Many new technologies fall into this trap to some degree, being the subject of a great deal of excited research but never bridging the gap into wide-scale implementation. For example, basically the entire field of computer usability.

Apple

What unstuck the GUI and pushed it into the world of industry? Basically Steve Jobs, although he too suffered a few false starts. The Lisa was technically advanced but a commercial failure, the Macintosh was a commercial success but relatively primitive. Nonetheless, the Macintosh was essentially the next major step from Engelbart's demo, and it established many of the norms for GUIs for years to come.

The relative success of the Macintosh compared to the costly but significantly superior Lisa is a rather unfortunate situation. For the most part, the Lisa was the more innovative and capable machine. The Macintosh was essentially a compromise, stripping out the most interesting features of the Lisa to achieve a low price and more gentle learning process. To be quite honest, the Macintosh sucked, which is why we far more often talk about its various successors.

I will probably devote an entire post to this, because I want to do the topic justice and did not intend to take it on here. But the Lisa was a document interface, while the Macintosh was a program interface.

This is actually the same paradigm we discussed in a previous post, of functional vs object-oriented user interfaces. Graphical operating systems that we use today are nearly entirely functional, with the operating system's role fundamentally being the launching and management of programs. It might be hard to picture anything else. But most early GUI research actually did envision something else, a fully object-oriented interface that is nearly entirely structured around documents and data. The Lisa was document-oriented, and Microsoft made various efforts towards a document-oriented Windows experience. But document-oriented interfaces were ultimately unsuccessful, and none survive today [3].

Despite the disappointing compromise of the Macintosh, it set the trend for most GUI systems to follow. The Macintosh interface was WIMP (Windows, Icons, Menu, Pointer), it had drag-and-drop file management (although it opened a new window for every folder the user descended into, an especially irritating element of early GUI operating systems that was fortunately cast off by the new millennium), and it used icons on a desktop as the primary entry point at menus at the top for access to commands.

Windows?

In the eyes of most, the next major step from the Macintosh was Microsoft Windows. Windows was introduced in its first version only a year after the Macintosh and a few years after the Lisa. Early releases of Windows, and to a degree all releases of Windows outside of NT, were simply applications which ran on top of DOS. This was a logical decision at the time, to build GUIs on top of a better established foundation, but it also imposed significant limitations.

In part as a result, the early versions of Windows were primitive and simply not that interesting. They were correspondingly unsuccessful, which is why you virtually never hear any mention of Windows 1.0 or 2.0.

The reason for the poor performance of Windows 1 and 2 is actually a surprisingly interesting and surprising one. It wasn't because Windows was inferior to the Macintosh; this was a factor to a degree but the Apple world was already highly differentiated from the PC world and the PC world had a formidable hold in the business world that ought to have conferred a big advantage on PC software.

It was more that early releases of Windows failed because they were inferior to other DOS GUIs.

The '80s PC world

Before we can get into the history of PC GUIs, we ought to devote some discussion to the context in which they were developed. Although IBM and others developed multiple operating systems for various generations of their personal computers, and thus for their many clones, by the '80s there was a high degree of consolidation on CP/M (for non-IBM small computers) and DOS (for IBM small computers and their clones). CP/M bears mentioning more so than other non-IBM operating systems of the time because, as a result of happenstance, CP/M was highly influential on the design of DOS which was intended to have a high degree of similarity to ease transition from one to the other.

We could almost say that DOS was a new version of CP/M, but the process was politically and technically rocky and various features of CP/M fell off the truck on the way to DOS. In the same way, some features of CP/M were carried into DOS even though they probably shouldn't have been. A number of DOS's oddities can be attributed to its origin as Microsoft Imitation CP/M Product.

So of the early non-Apple GUIs, most (but not all!) were intended to run on top of CP/M or DOS.

The thing is, CP/M and DOS were both primitive operating systems by modern standards. CP/M and DOS were not multi-tasking. They did not employ virtual memory, but instead addressed all memory directly. As a natural result of these two prior facts, they provided no isolation between running programs, and so the primitive "multitasking-like" behavior that could be implemented was very prone to problems.

If we were presented with this situation today, we might declare that development of a GUI environment on top of these operating systems is simply impossible. And yet...

[1] If the name Vannevar Bush is familiar to you, there could be any number of reasons as he had a prominent career. Perhaps most notably, as director of the OSRD, he was a major figure in the early development of nuclear weapons.

[2] The obvious solution to this problem, of integrating the mouse into the keyboard, was popular on '90s laptops but is largely forgotten today. A small group of trackstick devotees have managed to keep them on "business" laptops, a great benefit to myself. I cannot imagine life without a trackstick mouse, the only civilized way to move the cursor with both hands on the home row.

[3] In fact, Apple launched several different independent GUI operating systems in a span of a few years in the early '80s, the Macintosh being the only one that survived. One day I will write about these.

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>>> 2021-06-02 a history of powerpoint

A brief interlude from the topic of GUIs to talk about perhaps one of the most infamous of all GUI programs, Microsoft PowerPoint.

PowerPoint is ubiquitous but often criticized in most industries, but I have never seen more complete use and abuse of PowerPoint than in military. I was repeatedly astounded by how military programs invested more effort in preparing elaborately illustrated slides than actually, well, putting content in them. And that, in a nutshell, is the common criticism of PowerPoint: that it allows people to avoid actual effective communication by investing their effort in slides.

Nonetheless, the basic idea of using visual aids in presentations is obviously a good one. The problem seems to be one of degrees. When I competed in expository speech back in high school my "slides" were printed on a plotter and mounted on foam core. More so than the actual rules of the event, this imposed an economy in my use of visual aids. Perhaps the problem with PowerPoint is simply that it makes slides too easy. When all you need to do is click "new slide" and fill in some bullet points, there's nothing to stop the type of presenter who has more slides than ideas.

Of course that doesn't stop the military from hiring graphic designers to prepare their flowcharts, but still, I think the basic concept stands...

As my foam core example suggests, the basic idea of presenting to slides is much older than PowerPoint. I've quipped before that Corporate Culture is what people call their PowerPoint presentations. Most of the large, old organizations I've worked for, private and government, had some sort of "in-group" term for a presentation. For example, at GE, one presents a "deck." Many of these terms are anachronistic, frozen references to whichever presentation technology the organization first adopted.

Visual aids for presentations could be said to have gone through a few generations: large format printed materials, transparent slides, and digital projection. Essentially all methods other than projection have died out today, but for a time these all coexisted.

Printed materials can obviously be prepared by hand, e.g. by a sign painter, and this was the first common method of presenting to slides. Automation started from this point, with the use of plotters. As I have perhaps mentioned before the term "plotter" is a bit overloaded and today is often used to refer to large-format raster printers, but historically "plotter" referred to a device that moved a tool along vectors, and it's still used for this purpose as well.

Some of the first devices to create print materials from a computer were pen plotters, which worked by moving a pen around over the paper. HP and Roland were both major manufacturers of these devices (Roland is still in the traditional plotter business today, but for vinyl cutting). And it turns out that presentations were a popular application. The lettering produced by these devices was basic and often worse than what a sign painter could offer (but requiring less skill). What really sold pen plotters was the ability to produce precise graphs and charts directly from data packages like VisiCalc.

The particularly popular HP plotters, the 75 series, had a built-in demo program that sold this capability by ponderously outlining a pie chart along with a jagged but steeply rising line labeled "Sales." Business!

These sorts of visual aids remained relatively costly to product though until projection became available... large-format plotters, board to make things rigid, etc. are not cheap. Once you buy a single projector for a conference room, though, projection becomes a fairly cheap technology, even with the methods of producing slides.

The basic concept of projection slide technology is to produce graphics using a computer and then print them onto a transparent material which serves as film for a projector. There are a lot of variations on how to achieve this. Likely the oldest method is to produce a document using a device like a plotter (or manual illustration, or a combination) and then photographically expose it on film using a device that could be described as an enlarger set to suck rather than blow. Or a camera on a weird mount, your choice.

In fact this remained a very common process for duplication for a very long time, as once a document was exposed on film photochemical methods can be used to produce printing plates or screens or all kinds of things. There is a terminological legacy of this method at least in the sciences, where many journals and conferences refer to the final to-be-printed draft of a paper as the "camera-ready" version. In the past, you would actually mail this copy to them and they (or more likely their printing house) would photograph it using a document camera and use the film to create the plates for the printed journal or proceedings.

If you've seen older technical books or journals, you may have seen charts and math notation that were hand-written onto the paper after it was typewritten (with blank spaces left for the figures and formulas). That's the magic of "reprographics," a term which historically referred mostly to this paper to film to paper process but nowadays gets used for all kinds of commercial printing. This is closely related to the term "pasting up" for final document layout, since a final step before reprographic printing was usually to combine text blocks, figures, etc produced by various means into a single layout. Using paste.

For presentations, there are a few options. The film directly off the document camera may be developed and then mounted in a paper or plastic slide to be placed in a projector. If you are familiar with film photography, that might seem a little off to you because developed film is in negative... in fact, for around a hundred years "reversal films" have been available that develop to positive color, and they were typically used to photograph for slides in order to avoid the need for an extra development process. Kodachrome is a prominent example. Reversal films are also sometimes used for typical photography and cinematography but tended to be more complex to develop and thus more expensive, so most of us kept our terrible 35mm photography on negatives.

This approach had the downside that the slide would be very small (e.g. from a 35mm camera), which required specialized projection equipment (a slide projector). The overhead projector was much more flexible because the "film frame," called the platen, was large enough for a person to hand-write on. It served as a whiteboard as well as a projector. So more conference rooms featured overhead projectors than slide projectors, and there was a desire to be able to project prepared presentations on these devices.

This concept, of putting prepared (usually computer-generated) material on a transparent sheet to be placed on an overhead projector, is usually referred to as a "viewgraph." Viewgraphs were especially popular in engineering and defense fields, and there are people in the military who refer to their PowerPoint presentations as viewgraphs to this day. There are multiple ways to produce viewgraphs but the simplest and later on most common was the use of plastic sheets that accepted fused toner much like paper, so viewgraphs could either be printed on a laser printer or made by photocopying a paper version. When I worked for my undergraduate computer center around a decade ago we still had one laser printer that was kept stocked with transparency sheets, but people only ever printed to it by accident.

In fact, these "direct-print" transparencies were a major technical advancement. Before the special materials were developed to make them possible, overhead transparencies were also produced by photochemical means and use of a document camera and enlarger. But most large institutions had an in-house shop that could produce these with a quick turnaround, and they were still popular even before easy laser printing.

Not all projection slides were produced by photographing or copying a paper document, and in fact this method was somewhat limited and tended not to work well for color. By the '70s photosetting had become practical for the production of printing plates directly from computers, and it was also used to produce slides and transparencies. At the simplest, a photosetter is a computer display with optics that focus the emitted light onto film. In practice, many photosetters were much more complicated as they used shifting of the optics to expose small sections of film at a time, allowing for photosetting at much higher resolution than the actual display (often a CRT).

Donald Knuth originally developed TeX as a method of controlling a photosetter to produce print plates for books, and some of TeX's rougher edges date back to its origin of being closely coupled to this screen-to-film process. The photosetting process was also used to produce slides direct from digital content, and into the early '00s it was possible to send a PowerPoint presentation off to a company that would photoset it onto Kodak slides. Somewhere I have a bin of janitorial product sales presentations on slides that seem to be this recent.

The overhead projector as a device was popular and flexible, and so it was also leveraged for some of the first digital projection technology. In fact, the history of electronic projection is long and interesting, but I am constraining myself to devices often seen in corporate conference rooms, so we will leave out amazing creations like the Eidophor. The first direct computer projection method to become readily available to America's middle management was a device sometimes called a spatial light modulator (SLM).

By the 1980s these were starting to pop up. They were basically transparent LCD displays of about the right size to be placed directly onto the platen of an overhead projector. With a composite video or VGA interface they could be used as direct computer displays, although the color rendering and refresh rate tended to be abysmal. I remember seeing one used in elementary school, along with the 8mm projectors that many school districts held on to for decades.

All of these odd methods of presentation basically disappeared when the "digital projector" or "data projector" became available. Much like our modern projectors, these devices were direct computer displays that offered relatively good image quality and didn't require any of the advanced preparation that previous methods had. Digital projectors had their own evolution, though.

The first widely popular digital projectors were CRT projectors, which used a set of three unusually bright CRT tubes and optics. CRT projectors offered surprisingly good image quality (late-model CRT projectors are pretty comparable to modern 3LCD projectors), but were large, expensive, and not very bright. The tubes were often liquid cooled and required regular replacement at a substantial cost. As a result, they weren't common outside of large meeting rooms and theaters.

The large size, low brightness, and often high noise level of CRT projectors made them a bit more like film projectors than modern digital projectors in terms of installation and handling. They were not just screwed into the ceiling, rooms would be designed specifically for them. They could weigh several hundred pounds and required good maintenance access. All of this added up to mean that they were usually in a projection booth or in a rear-projection arrangement. Rear-projection was especially popular in institutional contexts because it allowed a person to point at the screen without shadowing.

Take a close look at any major corporate auditorium or college lecture hall built in the '70s or '80s and there will almost certainly be an awkward storage room directly behind the platform. Originally, this was actually the projection booth, and a transparent rear-projection screen was mounted in the wall in between. Well-equipped auditoriums would often have both a rear projection and front projection capability, as rear projection required mirroring the image. Anything that came in on film would often be front-projected, often onto a larger screen, because it was simpler and easier. Few things came in on film that someone would be pointing at, anyway.

You may be detecting that I enjoy the archaeological study of 1980s office buildings. We all need hobbies. Sometimes I think I should have been an electrician just so I could explain to clients why their motor-variac architectural lighting controller is mounted in the place it is, but then they'd certainly have found an excuse to make me stop talking to them by that point.

The next major digital projection technology on the scene was DLP, in which a tiny MEMS array of mirrors flip in and out of position to turn pixels on and off. The thing is, DLP technology is basically the end of history here... DLP projectors are still commonly used today. LCD projectors, especially those with one LCD per color, tend to produce better quality. Laser projectors, which use a laser diode as a light source, offer even better brightness and lifespan than the short arc lamps used by DLP and LCD projectors. But all of these are basically just incremental improvements on the DLP projection technology, which made digital projectors small enough and affordable enough to become a major presence in conference rooms and classrooms.

The trick, of course, is that as television technology has improved these projectors are losing their audience. Because I am a huge dweeb I use a projector in my living room, but it is clear to me at this point that the next upgrade will be to a television. Televisions offer better color rendering and brightness than comparably priced projection setups, and are reaching into the same size bracket. An 85" OLED television, while fantastically expensive, is in the same price range as a similarly spec'd projector and 100" screen (assuming ALPR here for more comparable brightness/color). And, of course, the installation is easier. But let me tell you, once you've installed an outlet and video plate in the dead center of your living room ceiling you feel a strong compulsion to use it for something. Ceiling TV?

So that's basically the story of how we get to today. Producing a "deck" for a meeting presentation used to be a fairly substantial effort that involved the use of specialized software and sending out to at least an internal print shop, if not an outside vendor, for the preparation of the actual slides. At that point in time, slides had to be "worth it," although I'm sure that didn't stop all kinds of useless slides to impress people with stars on their shoulders.

Today, though, preparing visual aids for a presentation is so simple that it has become the default. Hiding off to the side of slides is seen as less effort than standing where people will actually look at you. And god knows that in the era of COVID the "share screen" button is basically a trick to make it so people don't just see your webcam video when you're talking. That would be terrible.

There are many little details and variations in this story that I would love to talk about but I fear it will turn into a complete ramble. For example, overhead based projection could be remarkably sophisticated at times. You may remember the scene at the beginning of "The Hunt for Red October" (the film) in which Alec Baldwin gives an intelligence briefing while unseen military aids change out the transparencies on multiple overhead projectors behind rear-projection screens. This was a real thing that was done in important enough contexts.

Slide projectors were sometimes used in surprisingly sophisticated setups. I worked with a college lecture hall that was originally equipped with one rear projection screen for a CRT projector and two front projection screens, both with a corresponding slide projector. All three projectors could be controlled from the lectern. I suspect this setup was rarely used to its full potential and it had of course been removed, the pedestals for the front slide projectors remaining as historic artifacts much like the "No Smoking" painted on the front wall.

Various methods existed for synchronizing film and slide projectors with recorded audio. A particularly well-known example is the "film strip" sometimes used in schools as a cheaper substitute for an actual motion picture. Late film strips were cassette tapes and strips of slides, the projector advanced the slide strip when it detected a tone in the audio from the cassette tape.

Okay, see, I'm just rambling.

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>>> 2021-05-24 dialogs not taken

Note: I put up a YouTube video about a minor aerial lift disaster in northern New Mexico. You can see it here: https://www.youtube.com/watch?v=1NDc760fxbY.

Note 2: I have begrudgingly started using Twitter to ramble about the things I spend my day on. It's hard to say how long this will last. https://twitter.com/jcrawfordor.

When we look back on the history of the graphical user interface, perhaps one of the most important innovations in the history of computing, we tend to think of a timeline like this: Xerox, Apple, Microsoft, whatever we're doing today.

Of course that has the correct general contours. The GUI as a concept, and the specific interaction paradigms we are familiar with today, formed in their first productized version at the Xerox Palo Alto Research Center (XPARC). Their production version, the Alto, was never offered as a commercial product but was nonetheless widely known and very influential. Apple's early machines, particularly the Lisa and Macintosh, featured a design heavily inspired by the work at XPARC. Later, Microsoft released Windows 3.11 for Workgroups, the first one that was cool, which was heavily inspired by Apple's work.

In reality, though, the history of the GUI is a tangled one full of controversy ("inspired" in the previous paragraph is a euphemism for "they all sued each other") and false starts. Most serious efforts at GUIs amounted to nothing, and the few that survive to the modern age are not necessarily the ones that were most competitive when originally introduced. Much like I have perennially said about networking, the world of GUIs has so ossified into three major branches (MacOS-like, Windows-like, and whatever the hell Gnome 3 is trying to be [1]) that it's hard to imagine other options.

Well, that's what we're about to do: imagine a different world, a world where it's around the '80s and there are multiple competing GUIs. Most importantly, there are more competing GUIs than there are operating systems, because multiple independent software vendors (ISVs) took on the development of GUIs on top of operating systems like CP/M and DOS. The complexities of a GUI, such as de facto requiring multi-tasking, required that these GUIs substantially blur the line between "operating system" and "application" in a way that only an early PC programmer could love.

And that is why I love these.

Before we embark on a scenic tour of the graveyard of abandoned GUIs, we need to talk a bit about the GUI as a concept. This is important to comprehend the precedents for the GUI of today, and thus the reason that Apple did not prevail in their lawsuit against Microsoft (and perhaps Xerox did not prevail in their lawsuit against Apple, although this is an iffier claim as the Xerox vs. Apple case did not get the same examination as Apple vs. Microsoft).

What is a GUI?

I believe that a fundamental challenge to nearly all discussions about GUIs is that the term "GUI" is actually somewhat ill defined. In an attempt to resolve this, I will present some terminology that might be a better fit for this discussion than "GUI" and "TUI" or "graphical" and "command-line." In doing so I will try to keep my terminology in line with that used in the academic study of human-computer interaction, but despite the best efforts of one of my former advisors I am not an HCI scholar so I will probably reinvent terminology at least once.

The first thing we should observe is that the distinction between "graphics" and "text" is not actually especially important. I mean, it is very important, but it actually does not fundamentally define the interface. In my experience people rarely think about it this way, but it ought to be obvious: libraries such as newt can be used to create "gui-esque" programs in text mode (think of the old Debian installer as an example), while there are graphical programs that behave very much like textmode ones (think of text editors). Emacs is a good example of software which blurs this line; emacs simultaneously has traits of "TUI" and "GUI" and is often preferred in graphical mode as a result.

To navigate this confusion, I use the terms "graphics mode" and "text mode" to refer strictly to the technical output mechanism---whether raster data or text is sent to the video adapter. Think about it like the legacy VGA modes: the selection of graphics or text mode is important to user experience and imposes constraints on interface design, but does not fundamentally determine the type of interface that will be presented.

What does? Well, that's a difficult question to answer, in part because of the panoply of approaches to GUIs. Industry and researchers in HCI tend to use certain useful classifications, though. The first, and perhaps most important, is that of a functional UI versus an object-oriented UI. Do not get too tangled in thinking of these as related to functional programming or OO programming, as the interface paradigm is not necessarily coupled to the implementation.

A functional user interface is one that primarily emphasis, well, functions. A command interpreter, such as a shell, is a very functional interface in that the primary element of interaction is, well, functions, with data existing in the context of those functions. On the other hand, a modern word processor is an object oriented interface. The primary element of interaction is not functions but the data (i.e. objects), the available functions are presented in the context of data.

In a way, this dichotomy actually captures the "GUI vs TUI" debate better than the actual difference between graphics and text mode. Text mode applications are usually, but not always, functional, while graphical applications are usually, but not always, object oriented. If you've worked with enough special-purpose software, say in the sciences, you've likely encountered a graphical program which was actually functional rather than object oriented, and found it to be a frustrating mess.

This has a lot to do with the discovery and hiding of functionality and data. Functional interfaces tend to be either highly constrained (e.g. they are only capable of a few things) or require that the bulk of functionality be hidden, as in the case of a typical shell where users are expected to know the available functions rather than being offered them by the interface. Graphical software which attempts to offer a broad swath of functionality, in a functional paradigm, will have a tendency to overwhelm users.

Consider the case of Microsoft Word. I had previously asserted that word processors are usually an example of the object oriented interface. In practice, virtually all software actually presents a blend of the two paradigms. In the case of Word, the interface is mostly object-oriented, but there is a need to present a large set of commands. Traditionally this has been done by the means of drop-down menus, which date back nearly to the genesis of raster computer displays. This is part of the model or toolkit often called WIMP, meaning Windows, Icons, Menus, Pointer. A very large portion of graphics mode software is WIMP, and the WIMP concept today is exemplified by many GUI development toolkits which are highly WIMP-centric (Windows Forms, Tk, etc).

If you used Office 2003 or earlier, you will no doubt remember the immense volume of functionality present in the menu bar. This is an example of the feature or option overload that functional interfaces tend to present unless functionality is carefully hidden. It makes an especially good example because of Microsoft's choice in 2007 to introduce the "ribbon" interface. This was a remarkably controversial decision (for the same reason that any change to any software ever is controversial), but at its core it appears to have been an effort by Microsoft to improve discoverability of the Office interface through contextual hiding of the menus. Essentially, the ribbon extends the object oriented aspect of the interface to the upper window chrome, which had traditionally been a bastion of functional (menu-driven) design.

Menu-driven is another useful term here, although I tend to prefer "guided" as a term instead (this is a term of my own invention). Guided interfaces are those that accommodate novice or infrequent users by clearly expressing the available options. Very frequently this is by means of graphical menus, but there are numerous other options, one of which we'll talk about shortly. The most extreme form of a guided interface is the wizard, which despite being broadly lambasted for Microsoft's particularly aggressive use in earlier Windows versions has survived in a great deal of contexts. A much more relaxed form would be the "(Y/n)" type hints often shown in textmode applications. "Abort, Retry, Fail?," if you think about it, is a menu [2]. This guidance is obviously closely related to discoverability, basically in the sense that non-guided interfaces make little to no attempt at discoverability (e.g. the traditional shell).

Another useful term is the direct manipulation interface. Direct manipulation is a more generalized form of WYSIWYG (What You See Is What You Get). Direct manipulation interfaces are those that allow the user to make changes and immediately see the results. Commonly this is done by means of an interface metaphor in which the user directly manipulates the object/data in a fashion that is intuitive due to its relation to physical space [3]. For example, resizing objects using corner drag handles. Direct manipulation interfaces are not necessarily WYSIWYG. For example, a great deal of early graphics and word processing software enabled direct manipulation but did not attempt to show "final" output until so commanded (WordPerfect, for example).

This has been sort of a grab basket of terminology and has not necessarily answered the original question (what is a GUI?). This is partially a result of my innate tendency to ramble but partially a result of the real complexity of the question. Interfaces generally exist somewhere on a spectrum from functional to object-oriented, from guided to un-guided, and in a way from text mode to graphics mode (consider e.g. the use of Curses box drawing to replicate dialogs in text mode).

My underlying contention, to review, is this: when people talk about "GUI vs TUI," they are usually referring not to the video mode (raster or text) but actually to the interface paradigm, which tends to be functional or object oriented, respectively, and unguided or guided, respectively. Popular perceptions of the GUI vs. TUI dichotomy, even among technical professionals, are often more a result of the computing culture (e.g. the dominance of the Apple-esque WIMP model) than technical capabilities or limitations of the two. What I am saying is that the difference between GUI and TUI is a cultural construct.

Interface Standardization: CUA

In explaining this concept that the "GUI vs TUI" dichotomy is deeper than the actual video mode, I often reach out to a historic example that will be particularly useful here because of its importance in the history of the GUI---and especially the history of the GUIs we use today. That is IBM Common User Access, CUA.

CUA is is not an especially early event in GUI history but it's a formative one, and it's useful for our purposes because it was published at a time---1987---when there were still plenty of text-only terminals in use. As a result, CUA bridges the text and raster universes.

The context is this: by the late '80s, IBM considers itself a major player in the world of personal computers, in addition to mainframes and mid/minis. Across these domains existed a variety of operating systems with a variety of software. This is true even of the PC, as at this point in time IBM is simultaneously supporting OS/2 and Windows (2). While graphical interfaces clearly existed for these systems, this was still an early era for raster displays, and for the most part IBM still felt text mode to be more important (it was the only option available on their cash cow mainframes and minis).

Across operating systems and applications there was a tremendous degree of inconsistency in basic commands and interactions. This was an issue in both graphical and textual software but was especially clear in text mode where constraints of the display meant that user guidance was usually relatively minimal. We can still clearly see this on Unix-like operating systems where many popular programs are ported from historical operating systems with varying input conventions (to the extent they had reliable conventions), and few efforts have been made to standardize. Consider the classic problem of exiting vim or emacs: each requires a completely different approach with no guidance. This used to be the case with essentially all software.

CUA aimed to solve this problem by establishing uniform keyboard commands and interface conventions across software on all IBM platforms. CUA was developed to function completely in text mode, which will be somewhat surprising considering the range of things it standardized.

The most often discussed component of CUA is its keyboard shortcuts. Through a somewhat indirect route (considering the failure of the close IBM/Microsoft collaboration), CUA has been highly influential on Windows software. Many of the well-known Windows keyboard commands come from CUA originally. For example, F1 for help, F3 for search, F5 to refresh. This is not limited just to the F keys, and the bulk of common Windows shortcuts originated with CUA. There are, of course, exceptions, with copy and paste being major ones: CUA defined Shift+Delete and Shift+Insert for cut and paste, for example. Microsoft made a decision early on to adopt the Apple shortcuts instead, and those are the Ctrl+C/Ctrl+V/Ctrl+X we are familiar with today. They have been begrudgingly adopted by almost every computing environment with the exception of terminals and Xorg (but are then re-implemented by most GUI toolkits).

The keyboard, though, is old hat for text mode applications. CUA went a great deal further by also standardizing a set of interactions which are very much GUI by modern standards. For example, the dialog box with conventional options of "OK" and "OK/Cancel" come from CUA, along with the ubiquitous menu sequence of File first and Help last.

While being graphical by modern standards these concepts of drop-down menus and dialog boxes were widely implemented in text mode by IBM. From a Linux perspective, this is rarely seen and would likely be a bit surprising. Why is that?

I contend that there is a significant and early differentiation between IBM and UNIX interfaces that remains highly influential today. While today the dichotomy is widely viewed as philosophical, at the time it was far more practical.

UNIX was developed inside of AT&T as a research project and then spread primarily through universities and research organizations. Because it was viewed primarily as a research operating system, UNIX was often run on whatever hardware was available. The PDP-11, for example, was very common. Early on, most of these systems were equipped with teletypewriters and not video terminals. Even as video terminals became common, there were a wide variety in use with remarkably little standardization, which made exploiting the power and flexibility of the video terminal very difficult. The result is that, for a large and important portion of its history, UNIX software was built under the assumption that the terminal was completely line-oriented... that is, no escape codes, no curses.

IBM, on the other hand, had complete control of the hardware in use. IBM operating systems and software were virtually always run on both machines and terminals that were leased from IBM as part of a package deal. There was relatively little fragmentation of hardware capabilities and software developers could safely take full advantage of whatever terminal was standard with the computer the software was built for (and it was common for software to require a particular terminal).

For this reason, IBM terminal support has always been more sophisticated than UNIX terminal support. At the root was a major difference in philosophy. IBM made extensive use of block terminals, rather than character terminals. For a block terminal, the computer would send a full "screen" to the terminal. The terminal operated independently, allowing the user to edit the screen, until the user triggered a submit action (typically by pressing enter) which caused the terminal to send the entire screen back to the computer and await a new screen to display.

This mechanism made it very easy to implement "form" interfaces that required minimal computer support, which is one of the reasons that IBM mainframes were particularly prized for the ability to support a very large number of terminals. In later block terminals such as the important 3270, the computer could inform the terminal of the location of editable fields and even specify basic form validation criteria, all as part of the screen sent to the terminal for display.

Ultimately, the block terminal concept is far more like the modern web browser than what we usually think of as a terminal. Although the business logic is all in the mainframe, much of the interface/interaction logic actually runs locally in the terminal. Because the entire screen was sent to the terminal each time, it was uniformly possible to update any point on the screen, which was not something which could be assumed for a large portion of UNIX's rise to dominance [4].

As a result, the IBM terminal model was much more amenable to user guidance than the UNIX model. Even when displaying a simple command shell, IBM terminals could provide user guidance at the top or bottom of the screen (and it was standard to do so, often with a key to toggle the amount of guidance displayed to gain more screen space as desired). UNIX shells do not do so, primarily for the simple reason that the shells were developed when most machines were not capable of placing text at the top or bottom of the screen while still being able to accept user input at the prompt.

Of course curses capabilities are now ubiquitous through the magic of every software terminal pretending to be a particularly popular video terminal from 1983. Newer software like tmux usually relied on this from the start, and older mainstays like vi have had support added. But the underlying concept of the line-oriented shell ossified before this happened, and "modern" terminals like zsh and fish have made only relatively minor inroads in the form of much more interactive assisted tab completion.

IBM software, on the other hand, has been offering on-screen menus and guidance since before the C programming language. Well prior to CUA it was typical for IBM software to use interactive menus where the user selects an option, hierarchical/nested menus, and common commands via F keys which were listed at the bottom of the screen for the user's convenience.

While many IBM operating systems and software packages do offer a command line, it's often oriented more towards power users and typical functions were all accessible by a guided menu system. Most IBM software, especially by the '80s, provided an extensive online help facility where pressing F1 retrieved context-aware guidance on filling out a particular form or field. Indeed, the CUA concept of an interactive help system where the user presses a Help icon and then clicks on a GUI element to get a popup explanation---formerly common in Windows software---was a direct descendent of the IBM mainframe online help.

The point I intend to illustrate here is not that IBM mainframes were surprisingly sophisticated and cool, although that is true (IBM had many problems but for the most part the engineering was not one of them).

My point is that the modern dichotomy, debate, even religious war between the GUI and TUI actually predates GUIs. It is not a debate over graphical vs text display, it is a debate over more fundamental UI paradigms. It is a fight of guided but less flexible interfaces versus unguided but more powerful ones. It is a fight of functional interfaces versus object oriented ones. And perhaps most importantly, it is a competition of "code-like" interfaces versus direct manipulation.

What's more, and here is where I swerve more into the hot take lane, the victory of the text-mode, line-oriented, shell interface in computer science and engineering is not a result of some inherent elegance or power. It is an artifact of the history of computing.

Most decisions in computing, at least most meaningful ones, are not by design. They are by coincidence, simultaneously haphazard but also inevitable in consideration of the decades of work up to that point. Abstraction, it turns out, is freeing, but also confining. Freeing in that it spares the programmer thinking about the underlying work, but confining in that it pervasively, if sometimes subtly, steers all of us in a direction set in the '60s when our chosen platform's lineage began.

This is as true of the GUI as anything else, and so it should be no surprise that IBM's achievements were highly influential, but simultaneously UNIX's limitations were highly influential. For how much time is spent discussing the philosophical advantages of interfaces, I don't think it's a stretch to say that the schism in modern computing, between the terminal and everything else, is a resonating echo of IBM's decision to lease equipment and AT&T's decision to make UNIX widely available to academic users.

Some old GUIs

Now that we've established that the history of the GUI is philosophically complex and rooted in things set in motion before we were born, I'd like to take a look at some of the forgotten branches of the GUI family tree: GUI implementations that were influential, technically impressive, or just weird. I've already gone on more than enough for one evening, though, so keep an eye out for part 2 of... several.

[1] It is going to take an enormous amount of self-discipline to avoid turning all of this into one long screed about Gnome 3, perhaps the only software I have ever truly hated. Oh, that and all web browsers.

[2] Menus in text mode applications are interesting due to the surprising lack of widespread agreement on how to implement them. There are many, many variations across commonly used software from limited shells with tab completion to what I call the "CS Freshman Special," presenting a list of numbered options and prompting the user to enter the number of their choice. The inconsistency of these text mode menus get at exactly the problem IBM was trying to solve with CUA, but then I'm spoiling the end for you.

[3] This is a somewhat more academic topic than I usually verge into, but it could be argued and often is that graphical software is intrinsically metaphorical. That is, it is always structured around an "interface metaphor" as an aid to users in understanding the possible interactions. The most basic interface metaphor might be that of the button, which traditionally had a simple 3D raised appearance as an affordance to suggest that it can be pressed down. This is all part of the puzzle of what differentiates "GUI" from "TUI": graphical applications are usually, but not always, based in metaphor. Textmode applications usually aren't, if nothing else due to the constraints of text, but it does happen.

[4] This did lead to some unusual interaction designs that would probably not be repeated today. For example, in many IBM text editors an entire line would be deleted (analogous to vim's "dd") by typing one or more "d"s over the line number in the left margin and then submitting. The screen was returned with that line removed. This was more or less a workaround for the fact that the terminal understood each line of the text document to be a form field, and so there was some jankiness around adding/removing lines. Scrolling similarly required round trips to the computer.

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>>> 2021-05-19 telephone turrets

Let's talk about a bit of telephone history. Again. Normally, I am more interested in the switching equipment and carriers and not so much in the instruments---that is, the things that you plug in at the end of the line. There are a few that really catch my eye, though, and one of them is of course the phenomena of the trading turret.

A trading turret is a specialized telephone-like device typically used by day traders. The somewhat useless Wikipedia article describes a trading turret as being a specialized key system, which is useless to most people today as key systems are no longer common and few people know what they are. Nonetheless, it is basically true. I will leave out much discussion of key systems here because I will probably talk about them in depth in the future, but a basic explanation is that a key system allows users at multiple telephone instruments to each access all outside lines. This was a popular setup for businesses that were large enough to need multiple outside lines but too small to have a dedicated telephone operator, from their introduction in the 1930s to the development of affordable small PABXs[1] in the '90s.

Key systems still occasionally appear today and the topic can become somewhat muddled because late key systems tended to have "PABX features" and many PABXs, especially in the IP world, have "key system features." But the basic difference can be explained something like this: a PABX connects multiple users to each line, while a key system connects multiple lines to each user. They were often used for similar purposes with the difference being largely one of implementation, but key systems do have their specific niches.

One of those is the item we for some reason call a turret. The term turret is used today almost exclusively to refer to the item made for the securities industry, a trading turret. These formidable tanks of phones often provide multiple handsets and speakers and are more or less identified by a touchscreen or large set of soft buttons that allow one-touch access to a large number of contacts.

These are superficially similar to a large set of line buttons such as is seen on the "receptionist sidecar" available for many business phones---an extra plug-in module that offers a big set of line buttons which can be configured as speed-dials or even one-touch unattended transfers, so that a receptionist can easily transfer calls or call up for people without having to dial extensions all the time. However, turrets are more than just phones with a lot of line buttons.

It kind of raises the question: what is a trading turret? What really differentiates one from, say, a digital PABX phone with a sidecar?

This is just the kind of thing I contemplate in my private moments, but the issue came to the front of my mind when someone provided a mailing list I am a member of with an interesting document [2]. It is the 1974 Bell System Practice (BSP, basically a Bell System standard operating procedure) for the SAC Main Operating Base Turret. BSP 981-202-100 if you are particularly interested.

The document describes a desk-wide system with ten color-coded handsets used at a Strategic Air Command base to give a communications operator quick access to primary and redundant versions of multiple communications lines. For flavor, two of these handsets were red and corresponded to primary and secondary four-wire leased line circuits used for the SAC Primary Alerting System, used to deliver emergency action messages. Here we have a real red telephone, but not to Moscow.

This makes it clear that the term "turret" is not specific to the finance industry, which was actually a bit of a surprise to me. Where, then, did we get the turret as a type of telephone instrument?

The first usage I have found is the Order Turret No. 1, introduced by the Bell system sometime in the early 1930s (exactly date unclear). The No. 1 is essentially a small manual (cord-and-plug) exchange that accommodates multiple user "positions." A series of subsequent Order Turrets, up to at least the No. 4, were produced in the first half of the century.

I was initially a bit unclear on the application of these devices (I found BSPs on them, but these have a great way of describing maintenance and repair in detail without ever saying what the thing is for) until I found an article in the Bell Laboratories Record, an employee magazine, of 1938. The article describes the use of the No. 4, now a more compact design which can be scaled to an arbitrary number of operators, as it was used at Macy's. It is called an Order Turret, it turns out, because it is used to place orders.

The system looks something like this: 20 (or another number, but we'll say 20, which was the capacity of the apparently common Order Turret Number 2) outside lines are assigned sequential numbers at the telephone exchange with busy fall through such that a call to the first line, if it is in use, will connect to the next line, and so on until a free line is found. At the turret, the call "appears" on a jack in front of each attendant. Whichever attendant is not currently busy can insert a plug to answer the call. In this way, the turret system allows a pool of attendants to collectively answer a pool of incoming lines.

But there's more: these attendants are taking telephone orders in a department store, where the actual stock is out on the floor in various departments. So if a customer asks about a particular item, the attendant can insert a plug into a jack for an internal line to that department, ringing a phone on the floor so that the attendant can speak with a salesperson to confirm availability and have the item set aside. The turret is used not only to answer calls, but to simultaneously manage multiple calls between different parties.

So far as I can tell, this is the defining feature of a turret: a turret isn't just used to handle multiple lines (that's a key telephone). A turret isn't just used to have rapid access to many speed dials (that's a receptionist sidecar). A turret is used to make multiple simultaneous calls, by someone who must quickly relay information between multiple parties. Like the telephone order attendant at an old-fashioned department store, the person on communications duty at a SAC command, or an investment banker.

This explains of course why both legacy and modern turrets often feature multiple handsets (the original Order Turrets did not, but the attendant wore a headset that they would move between jacks instead). As telephone systems have become more sophisticated, turrets have as well, and modern turrets often use IP connectivity to provide a mix of features like squawk boxes (permanently open conference lines), presence information, and a feature with various names (sometimes called automatic ringdown although this is not quite accurate) that allows one trader at a turret to call another trader at a turret with no ringing---the call just connects immediately, much like an intercom. All of this can be done very quickly, because the turret provides a large set of pre-programmed buttons for all the people the user is likely to want to contact.

You can already see that the application I've described for these early turrets, of order taking, could be handled differently. An obvious enhancement is to actively distribute calls to available attendants instead of presenting calls at all attendant stations and waiting for someone to pick up. Indeed, the Order Turret No. 4 did exactly this, actively "pushing" each incoming call to an available attendant. This increase in sophistication, to actively routing calls, really blurred the line between the order turret and the PABX, which Bell was well aware of. The No. 4 was less an order turret in the sense of previous designs, and more just a feature of a PABX.

The order lines, instead of being dedicated lines going straight to turrets, were just the normal incoming lines of the business PABX. The business PABX allocated calls to attendants sitting at the No. 4 stations. This is basically how modern inward call center systems work, and it seems that over time the concept of the "order turret" faded away as these call center queue systems became just another feature of a PABX.

Turrets found few niches in which to hold on. The SAC command turret tells a bit of a story about the close relationship between the Cold War defense complex and the Bell System. Large portions of SAC infrastructure were essentially contracted to AT&T, and so AT&T apparently drew on their background with order turrets in developing the concept for the SAC communications system, which in its totality consisted of a dizzying number of two- and four-wire leased lines and radio links unified by these eight-foot-wide turrets. They even controlled the sirens.

No doubt there were other turrets designed by Ma Bell, although I have struggled to find them. The Order Turret series seems to have died away by the mid-century, but the SAC command turret likely remained in use into the '80s at least. Can we find any others?

An obvious application for a turret-like system is in police and fire dispatch, where in many smaller communities emergency calls were taken directly by the dispatcher who then had to relay information on the radio. Indeed, various vendors have sold telephone equipment for dispatch and public safety answering points (PSAPs, where 911 is answered) described as turrets, but the terminology does not seem to have caught on as strongly in that field. I would suspect this is because radio equipment was often more important in these early dispatch centers than telephone, and indeed the complex communications consoles in public safety dispatch centers usually come from radio vendors (e.g. Motorola) rather than telephone. Radio vendors usually just call these "dispatch consoles" and they have gone through a similar evolution from electromechanical to IP.

There is one exception which stands out: in the city of Boston, the central dispatch office is apparently colloquially referred to as "the turret." The recordings of police radio traffic, sometimes used as evidence in court, are often referred to as "turret tapes" in Massachusetts. I am not certain that the terms are related but it would seem likely; I would speculate that at some point in history the concept of dispatchers using turrets turned into dispatchers working at the turret.

The funny thing here is that I've gone on for a long time without addressing my original interest: why is it called a turret? Well, after all the digging through BSPs and newspaper archives and a whole detour through court records, I still haven't quite answered that question. No one seems to have written down an etymology.

All I can offer is this theory: while turret most directly refers to a tower, through the path of gun turrets it has also come to refer to something that rotates (e.g. in the case of a turret lathe). The original Order Turrets consisted of a rectangular table around which four attendants would sit, two on each side. Perhaps they were called turrets because the attendants sat in a circle and the duty to answer the next call rotated around.

Just a guess.

[1] Today we usually just use the term PBX, for Private Branch eXchange. I specify PABX, for Private Automatic Branch eXchange, in the historical context because for decades the term "PBX" referred mostly to manual boards with dedicated operators, which used to be common in businesses, hotels, etc. A PABX is an automatically switched system, basically the PBX equivalent of the introduction of dialing.

[2] I am leaving the person and list here anonymous out of respect for the community's privacy, although it is an excellent resource if you're interested in these topics and I feel a bit bad for not giving credit. The name of the list rhymes with, uhh, OldDoorBombs.

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