Today I learned of the death of Herb Grosch, proud provocateur and mischief-maker of the computing industry. Anybody who ever knew Herb, however slightly or briefly, has a story to tell, so here’s mine.

Grosch held senior positions at major household-name companies (IBM, General Electric) as well as in the U.S. government; he also spent time at MIT and Columbia and was editor of Computerworld. But through it all he cultivated the role of the outsider, or even the outcast; he saw himself as a lone wolf; at IBM they labeled him a “wild duck.” He boasted that he was the second scientist ever hired at IBM (after Wallace Eckert) and, more important, was the first employee with facial hair. Even when he was an insider he was an outsider. Grosch was elected president of the Association for Computing Machinery–but as a dissident candidate, opposing the slate annointed by the nominating committee.

The free-spirited maverick is a celebrated figure in American culture, but not always a well-rewarded one. Wild ducks don’t get tenure, or a pension.

My brief encounter with Herb came ten years ago, when I was working on an article (PDF) about the uses of ternary notation in computing. I read somewhere that Grosch had proposed a ternary architecture for the Whirlwind, Jay Forrester’s enormous early electronic computer. The idea of a base-three machine probably seems weirder today than it did in the early 1950s, but all the same the proposal was not adopted, and most histories of the Whirlwind project say little or nothing about the ternary option. I had no luck finding a copy of Grosch’s memo on the subject, so I tried getting in touch with him directly. With the help of friends I tracked him down, though not in the first place I looked. He was in Riga, Latvia.

Grosch couldn’t supply a copy of the memo; most of his papers, he said, were buried in a landfill in Switzerland. The best he could do was point me to a passage in his autobiography, summarizing a conversation with Forrester:

I said what might be genuinely gainful would be to store a ternary digit in each core, and calculate in base-three rather than binary fashion. There were materials–some kinds of permalloy, as I remember–that had north, south and neutral stable magnetic states. I told him I had taught my Poughkeepsie evening classes at IBM about a special kind of base-three arithmetic I called “signed ternary,” in which zero was in the middle of the number range. In this curious system there was no need for algebraic signs, no problem about the sign of zero, and you rounded perfectly by dropping digits.

Jay being a stiff type, I refrained from calling the ternary digits “tits,” a name which had been the source of much boyish amusement in the Poughkeepsie classes.

By the way, I’m still looking for a copy of that memo. Here’s the reference: Grosch, H. J. R. 1952. Signed ternary arithmetic. Memorandum M-1496, Digital Computer Laboratory, MIT.

Of course I had to ask Herb how and why he’d found his way to Latvia. It was a long story, involving a small NSF grant, archives of Datamation magazine, a collection of Soviet-era computer hardware in an attic at Latvia University, and a romance that Herb hoped would develop into his fifth marriage. But the grant ran out, the marriage plans faltered, and Herb was heading back to U.S. in dire need of employment. His hopes, he said, were “not much above fast-foodery: editing, or tech writing, or even clerking at Barnes and Noble.” He was 82 at the time.

In the end, he did not have to stoop quite so far as editing or tech writing, or Barnes and Noble; he became Adjunct Distinguished Professor of Computer Science at the University of Nevada Las Vegas. But that posting didn’t last long. A few years later he turned up in Toronto, teaching the history of computing, but by then I’d lost touch with him.

In a “Dear Everybody” message some years ago, Grosch wrote:

I begin this letter on the fourth of six recent Binary Days, 01.11.01…. The next Binary Day will be nine years from now, 01.01.10, and I will write again then if I survive. Shorter recipient list, I assume!

Herb did make it until 01.01.10. He died January 25th. For more on his life and works, see the ACM obituary and a web site at Columbia maintained by Frank da Cruz.

It seems the great spam tide of 2009 is ebbing. The graph records numbers of spam messages per month received by my email accounts; obviously this is just a personal tally and your milage may vary. The percentage of Russian-language spam in my inbox has fallen off somewhat, from more than half last fall to less than 40 percent in January. (For context see my earlier bit-player spam reports: Aug 2009, May 2009, Mar 2009, Nov 2008, Oct 2008, Jun 2008. Also two American Scientist columns: Jul-Aug 2007 and May-Jun 2003.)

I would also like to draw attention to a recent article on the economics of spam: “Spamalytics: An Empirical Analysis of Spam Marketing Conversion,” by Chris Kanich, Christian Kreibich, Kirill Levchenko, Brandon Enright, Geoffrey M. Voelker, Vern Paxson and Stefan Savage, Communications of the ACM 52(9):99-107 (available online if you or your library is a subscriber). (Preprint link, thanks to Arvind Narayanan in the comments.) Kanich et al. adopt a clever and mildly controversial strategy: They parasitize an existing spam botnet and alter outgoing emails so that embedded links point back to the investigators’ own web servers, rather than those of the spammers. They write:

Using this methodology, we have documented three spam campaigns comprising over 469 million emails. We identified how much of this spam is successfully delivered, how much is filtered by popular antispam solutions, and, most importantly, how many users “click-through” to the site being advertised (response rate) and how many of those progress to a “sale” or “infection” (conversion rate).

Of the 469 million messages, 347 million were part of a campaign advertising pharmaceuticals. The bottom line: 28 “sales” (no money actually changed hands, and no products were delivered) with an average purchase price of about $100. This is a conversion rate of less than 1 in 10 million, which leaves some doubt about the profitability of the operation. Kanich et al. note that spam-for-hire services would charge roughly $25,000 to send 350 million emails, an order of magnitude more than the revenue generated in this campaign. Yet the mere continued existence of spam argues that the actual costs must be much lower. Kanich et al. speculate that the spammers are a vertically-integrated enterprise: They own both the botnet and the pharmacy.

Finally, I want to update my comment on comment spam. Three months ago I installed the Akismet filter to intercept spam comments submitted to bit-player. The filter has been performing fairly well, blocking about 200 spam comments so far, letting a dozen or so slip through, and falsely imprisoning a couple of legitimate comments. (Advice to commenters: Avoid ALL CAPS.)

Looking through the archive of impounded messages, I am more perplexed than ever about the social and economic basis of this phenomenon. The URLs that constitute the payload of the spam point to a weird miscellany of topics. Someone out there thinks that the readers of this blog are interested in hypnotism, in bathroom faucets and shower enclosures, in garage doors and currency conversion. Most of all we are a musical bunch: Fully a third of the spam comments promote merchandise related to pianos.

Unlike email spam, the comment spams are not generated by an automaton; there are living human beings at the other end of this communication channel. And apparently the spam writers are not hired merely for high-speed, wholesale captcha-solving. In many cases there is ample evidence that the commenter has read the article and understood it, and may even have something interesting to say about it.

It occurs to me that this circumstance gives me an opportunity to open a dialogue. So I now address myself directly to the comment spammers: If you are reading this post because you’ve been hired to plant comments and URLs here, or if you’re doing it for your own commercial gain, I have a proposition for you. Please leave a comment attached to this post, explaining what you’re doing and why–and, if possible, for whom. Tell us what a successfully planted link is worth, and how much you get out of it. If your comment is sufficiently interesting and informative, and if it seems genuine, I’ll let it through the Akismet filter, and you’ll have your chance to sell my readers a piano or a garage door. (This offer applies only to comments attached to this article, and I’ll be the sole judge of what’s interesting, informative and genuine.)

If you’d rather communicate privately, send me an email at brian@bit-player.org.

I got caught Wednesday night in the national pre-Thanksgiving traffic jam. As I was approaching Baltimore, an electronic signboard announced:

Of course I immediately thought: But everyone will read the sign and take I-695, so that road will be jammed too. Then I thought: But everyone who reads the sign will realize that everyone else will also read the sign, and so they’ll not choose 695. Then I thought….

Hmm. There’s something familiar about this problem.

I’m not telling which road I took, but I can report that it was the only congestion-free segment of my trip.

Someone out there is being paid to post comments on bit-player.org–and doubtless on tens of thousands of other blogs as well. The comments are mostly bland and inoffensive, sometimes effusive, always hastily composed. “Thanks for article..good work,” they say. “Amazing!!” “i like your article and i will be wating your net article….”

The payload attached to each of these comments is a link to a web site that someone wants to promote. Some of the sites are selling goods or services; others are billboards full of pay-per-view ads; a fair number are mysterious to me, being written in languages I don’t understand. I would not be astonished to learn that some of the sites are distributing malware.

Years ago, the first wave of comment spam was powered by scripts that flooded blogs and wikis and forums with hundreds of postings full of program-generated gibberish and long lists of links. That abuse was stopped by captchas and other simple filters, like the one I’ve been using here on bit-player. Another important defense is the “nofollow” tag, which instructs search engines to ignore links in comments, thereby eliminating the incentive of gaining PageRank points.

The comment spam arriving now is not generated by a Perl script. Somewhere in the world a person is being paid to read these very sentences, then to prove his or her humanity to the Turing-test filter, and finally to write a few words in response and sneak in a paid link. I’m both fascinated and appalled to learn that the Internet economy can support this activity. What’s the going rate for writing comment spam? Is it worth a penny to get your link briefly exposed to the vast daily readership of bit-player.org? How about a tenth of a penny?

I have a sinking feeling that the people doing this work are themselves victims of a scam, and that they’ll never see even the tenth of a penny. They have probably succumbed to a 21st-century version of the ads I used to see on matchbook covers: “Work at home! Make $500 a week stuffing envelopes in your spare time!”

Of all the ways that poor and desperate people are exploited, this is not the worst. Presumably the work is safe and sanitary, and it even rewards literacy. Some of my comment spammers would surely have interesting ideas to contribute if only they had the luxury of time.

All the same, this kind of commercial graffiti is not something I want to encourage. The available countermeasures include prohibiting all links in comments, holding all comments until a moderator approves them, or requiring commenters to register with a verifiable email address. None of these options appeals to me, but I may have to consider them if the problem persists. For now, though, I’m going to continue the human approach–manually deleting spammy comments as quickly as I can get to them. I am also closing comments on all but the 10 most-recent items on bit-player; the spammers seem to favor older posts.

I have to add that spotting comment spam is not always as easy as you might think. Consider this comment, which came in response to a story about editorial changes at Scientific American magazine:

Many times, when i read your American Scientist columns, I have asked myself that is any other country’s scientist didn’t give anything to the world?

The text of the comment is pertinent to the topic; it raises a question that’s entirely appropriate in this context; and there’s clear evidence that the author has actually been reading bit-player (and even my American Scientist columns) rather than merely spewing comments at random. This is someone I would like to be able to welcome into the community. But the link associated with the comment was an ad for a web-hosting service, and another comment from the same IP number advertised a different service. Was I wrong to hit the delete button?

You’re welcome to comment below, but without spammy links, please.

Sometime this morning, a web page that I visit occasionally changed its appearance from this:

to this:

The images are grabbed from Firefox on OS X; same effect in Safari. Some CSS forensics reveals what’s gone wrong here: Google has added a “height:28px” property to the style for the two buttons, and boosted their type size from 13 pixels to 16. (Type inside the search box is also given the giant billboard treatment.) Apparently the height property prevents the browser from using those cute jelly-bean widgets for the buttons.

Can we strike a bargain, Google? I’ll let you take over the world and track my every movement; I’ll sign over all my copyrights and promise never to block your advertising, if you’ll just give me my widgets back. Go ahead and Be Evil; just Don’t Be Ugly.

Or am I going to have to override you in userContent.css?

Update: Marissa Mayer, Google’s Vice President for Search Products & User Experience, explains:

For us, search has always been our focus. And, starting today, you’ll notice on our homepage and on our search results pages, our search box is growing in size. Although this is a very simple idea and an even simpler change, we’re excited about it — because it symbolizes our focus on search and because it makes our clean, minimalist homepage even easier and more fun to use. The new, larger Google search box features larger text when you type so you can see your query more clearly. It also uses a larger text size for the suggestions below the search box, making it easier to select one of the possible refinements.

For Firefox users who find the “supersized” page a nonimprovement, I offer the following quick hack:

@-moz-document domain(google.com) {
  .lsb, .gac_sb {
	font-size:13px ! important;
	height:inherit ! important;
	}

  .lst, .gac_m {
	font-size:14px ! important;
	}

}

Add these lines to your userContent.css file (see the Customizing Mozilla site for further instructions). This seems to fix the widget problem and the input-field text size, but all the drop-down gadgetry is still a mess and maybe the dropdown menu of suggestions. This will break if Google’s next whim is to change the class names “lsb,” “lst,” etc. If anyone has a cleaner solution, please pass it on.

July brought quite an impressive spam storm, which dumped 10,738 messages on me:

That’s a record for my inbox, well beyond the spike of 7,506 messages received last October. The mean number of messages over the two-year period shown is 3,867; the standard deviation is 2,190.

I’m intrigued by the amount of noise in this signal. The magnitude of the fluctuations suggests to me that somewhere in the spam economy there is a small-number bottleneck. Maybe there are only a few high-volume spammers in the world, so that when one of them goes on vacation, the overall volume sinks dramatically. Or maybe there are only a limited number of customers willing to pay for big spam mailings, so that the renewal or cancellation of a single contract can have a noticeable impact. Or it could be that there are only a few major lists of harvested email addresses; when the scraper misses one of my mailboxes, I see a big change.

A bottleneck of this kind is not the only possible explanation. In some other areas with high volatility–the stock market, for example–the apparent cause is not a small population of agents but strong correlations between agents, who all follow the same signs and signals. I suppose that might happen in the spam market, too, with broader economic trends affecting everyone in the same way, but somehow it seem less likely.

The graph below breaks down the monthly totals according to which of my various email addresses the spam targeted. Again the numbers seem to be bouncing around pretty wildly. For example, the July spike mostly came from my address here at bit-player, but the peak last October was dominated by an address at amsci.org.

Of the seven addresses I monitor, five are openly published on the web, and thus I shouldn’t be surprised that they attract their share of spam. But the other two addresses have never been published, and one of them I have never used or even handed out to friends. Those obscure addresses are getting about 1,000 spams a month in total.

One feature of my spam that doesn’t seem to fluctuate much from month to month is the proportion written in Russian or other languages that use the cyrillic alphabet. The fraction has hovered near one-half for the past year. I have a hard time imagining a model that produces such linguistic stability along with volatility in other dimensions.

In recent weeks my junk-mail folder has received well over 100 copies of the folksy image reproduced above. I don’t read Russian, but I know just enough of the alphabet to sound out the second word of the headline. My русскоговорящего friend Dana MacKenzie kindly translated the rest of the message:

Village Spammer

The era of posters and announcements has passed. We will distribute your ad on the Internet.

As Dana points out, this is spam for spammers: metaspam. There’s a lot of that going around. After all, the entire online economy is supported by advertisements for companies supported by advertisements for companies supported by….

Incidentally, the painting that the spammers defaced is “Village Postman,” 1959, by Pyotr Krokhonyatkin. I identified it by guessing the title and running a query through Simple Image Search, which led me here.

While I’m on the subject of spam, here’s an update to my running tally of monthly receipts:

For March and April combined, 57 percent of my spam was in Russian (or some other language that uses the Cyrillic alphabet).

My “Computing Science” column in the new issue of American Scientist looks at economics—including the current malaise—through the lens of control theory. This is not a new idea. The Keynesian prescription for smoothing out cycles of boom and bust is essentially an application of feedback control, although Keynes himself never described it that way. By the late 1940s the connection became explicit, as economists and control engineers worked together to refine tools for taming the business cycle. The two disciplines had another flirtation in the 1970s. Economists today seem less enthusiastic about methods borrowed from control theory, but they have certainly not given up on the aim of bringing the economy under control. In the past six months governments and central banks have intervened on a scale never seen before, all in an effort to “stimulate” economic recovery.

I’ll let the column itself tell the rest of this story; here I would just like to add a a couple of personal reminiscences about control engineering as seen by an interested outside observer.

Over the years I’ve had the opportunity to visit a lot of control rooms—at oil refineries, power plants, steel mills, railroad switch yards, sewage-treatment plants, particle accelerators, observatories, Internet operations centers. They’re not all exactly alike, but they do seem to share a common architecture, and also aspects of a common culture. For example, standard control-room iconography shows normally running machinery in red, whereas stopped or faulty equipment is green—the opposite of what you might guess after a lifetime of exposure to traffic lights. Years ago most control rooms had a “mimic board”—a long wall covered with a schematic diagram of the plant, festooned with gauges and switches and indicator lights. Now the operators are more likely to sit at ordinary computer screens. (I do hope they’re not watching YouTube videos while the reactor melts down.)

Two control rooms at the same plant—a paper mill in Catawba, South Carolina—serve to frame my impressions.

One of those rooms was in charge of a papermaking machine, a stupendous contraption the size of a football stadium, which takes in a slush of digested trees at one end and delivers huge reels of pristine white paper at the other end, with the sheet of paper-to-be threading between banks of steel rollers at a rate of more than 60 kilometers per hour. The control room for the paper machine was a calm and laid-back place. I sat with an engineer for an hour or so, talking about the thundering machinery outside the soundproofed booth, and all the while keeping an eye on the display screen in front of us. The indicators hardly budged the whole time. One key set of sensors in the papermaking process monitors the thickness of the moving sheet; if the thickness varies from the set point, a correction is made by blowing either warm or cool air onto one of the steel rolls. The temperature change causes the roll to expand or contract very slightly, and thus to squeeze the sheet a little more or less tightly. This is a subtle adjustment. Here’s what I wrote about it at the time:

It should be noted that the overall control strategy in papermaking is to operate the machine in a stable, steady-state condition. Blowing hot air on a steel roll cannot effect a large or a rapid change in the roll’s diameter; in the vocabulary of control theory, the actuators for this system have only limited authority. The limitation is intentional. The paper machine must run continuously for long periods, and changes in its state are designed to be gradual and confined to narrow bounds.

The other memorable control room at the Catawba mill was in the powerhouse, where boilers generate steam needed throughout the plant, as well as electricity. The main fuel for the boilers is “black liquor,” a strange watery brew created in the digesters that leach lignin and other kinds of organic gunk out of the wood. Black liquor is not a particularly good fuel, but the plant has to get rid of the stuff anyway, so burning it makes sense. But because of wide variations in the caloric value of the liquor, the boilers are hard to control. The first thing I noticed when I sat down with an operator in the powerhouse control room was that all the finish had been rubbed off one area of the console, surrounding a button whose label had also been rubbed away. I soon learned the function of that button: It silenced the alarm buzzer that sounds whenever some parameter wanders out of bounds. On the day of my visit, the buzzer was going off every minute or two. The operator displayed a well-developed Pavlovian reflex, slapping the silence button in milliseconds every time the buzzer sounded. Then he would turn to the screen, find the cause of the problem, and make some adjustment to fix it. Thus the powerhouse control room was a much busier place, and the mood was tense. If I had been doing that job, I’d have been ready for a beer at the end of my shift.

Somewhere in the bowels of the Treasury Department or the Federal Reserve (or maybe the World Bank), there must be a control room where operators at glowing screens watch the ebb and flow of money and make adjustments when some economic parameter strays from the set point. I wonder about the mood of that room. Is it one of those placid, hushed working environments, where controllers gently nudge the system back toward equilibrium? Or are they batting at buzzers all day?

Sometime in the early 1980s my friend Greg Chaitin decided to go digital. He wanted to have all of his own writings, along with some other documents he particularly valued, ready at hand in machine-readable form. This was long before Postscript or PDF; scanners and OCR were exotic technology. So Greg hired a typist. I know about all this because he sent me a printout of his digitized oeuvre—an impressively thick sheaf of fanfold paper, with sprocket strips still attached. (The irony of this mode of distribution was not lost on either of us.)

I’m finally trying to catch up with Greg. Instead of hiring a typist, though, I’ve bought a cute little document scanner, which has been busily transforming heaps of moldering cellulose into shiny new bits. The scanner produces PDFs, which then run through an OCR program to build an index, making the page images searchable. (Bring on the Googlebot!) The result falls short of ideal—files are obese, graphics are low-res, there’s no opportunity to edit or reformat—but still it’s better than rummaging through cobwebby filing cabinets in my basement. And I don’t have to FedEx cartons of fanfold to my friends.

I’ll be adding links to my publications list as I upload the files. Here are a few teasers:

The HP-41C: A Literate Calculator? Byte, January 1981, pages 118-138. PDF (3.3 MB)

40,000 Points of Light. Pixel, Vol. 1, No. 2, May-June 1990, pages 36-41. [On a graphics language in which an image is defined as a locus of points.] PDF (2.4 MB)

Rank-and-File Thinking. Lotus, June 1985, pages 73-77. PDF (1.8 MB)

Theory & Practice: On the bathtub algorithm for dot-matrix holograms. Computer Language, October 1986, pages 21-32. [On patterns generated by severely oversampled signals.] PDF (4.6 MB)

The Information Age: The Numbering Crisis in World Zone 1. The Sciences, Vol. 32, No. 6, November-December 1992, pages 12-15. [On the impending shortage of telephone numbers.] PDF (1.8 MB)

I note for the record that every one of the publications mentioned in the list above is now defunct. I wonder if there’s any significance in that?

I get a daily Google Alert with news of web pages that mention my books. Lately the alerts have been pretty weird. I’m not going to publish the URLs because I’m not sure what mischief is behind all this, and many of the pages have been taken down already anyway, but here are a couple of text excerpts.

This one—and dozens like it—appears to be the output a Perl script with an overused $book_title variable and a shaky grasp of English syntax:

You need to know that Group Theory in the Bedroom and Other Mathematical Diversions is an beautiful product! I love my Group Theory in the Bedroom and Other Mathematical Diversions alot! I Track down the grade a quality of Group Theory in the Bedroom and Other Mathematical Diversions is just dazzling! I purchased my Group Theory in the Bedroom and Other Mathematical Diversions at Amazon.com and found that they have the half-price prices online for Group Theory in the Bedroom and Other Mathematical Diversions!

As far as I can tell, the aim of these web pages is actually to sell copies of the book (through an Amazon Associates link that earns the referrer a small kickback). I guess I should wish them every success.

Another set of pages is more enigmatic both in garbledness and in purpose. Under a conventional-looking heading that suggests some sort of book-review service, there are great gobs of prose like this:

In the imaginative, legendary readable Infrastructure: A Field Guide to the Industrial Landscape, Brian Hayes adapt the genre of the graze manor guide to “everything that isn’t nature,” as he writes. Hayes take on the destined thicket of specialized gobbledygook gracefully, adding up comparison to brand name contemporary lingo and process reasonable. A method of floodgates works “like a rolltop desk”; bricks are “sliced from an extruded flex of sand by a magnificent wire, like a cheese cutter. Now a veteran science writer has crisscrossed the U. The perfume was deep but not sickly sweetie. ” Along country roads, Hayes explore all the technological sights, from tractors and combine to the earlier extent and decoration of the once dominant technology for enclose animals, barbed wire: “As bedside light as air. He undertake this mission to some extent through hundreds of photographs taken from airplanes, cars, and the public side of many a chain-link balustrade, partly through the moving on, accessible prose of a man who appreciate the history, engineering, and aesthetics of such wonder as barn hay hood, grain elevators, oil pipelines, and the airing towers of the Holland Tunnel. Cheaper than dust,” as one of its unwary proponents describe it. Down sewer manholes: “Sounds were deadened. “It’s all in circle you. Industrial buildings Landscape architecture..

I recognize the underlying text from which this pastiche was constructed: It’s from a review by Anne Eisenberg, originally published in Scientific American but also posted on Amazon. Phrases have been scrambled and also altered with aid of a thesaurus. For example, “many a chain-link fence” in the original review has become “many a chain-link balustrade,” and the ventilation towers of the Holland Tunnel are now “airing towers.”

What I can’t figure out is why. Why did the splogger bother to alter the text at all? Why not just scrape it and spew it? Surely someone who would post this sort of stuff isn’t worried about copyright violations. Beyond that, why bother at all? On these pages there are no links to Amazon—or to anything else in the known universe, so what’s the point? What is it all in aid of? I suspect the motive has something to do with getting the page indexed by Google—and in that they’ve evidently succeeded—but then what? I don’t see the payoff.

A roundup of other spam news:

The graph below brings up to date my monthly tally of junk email. It looks like we’re back on the upward growth path, recovering from the crash at the end of last year. Also, the proportion of my spam in Russian keeps climbing. It had been running about half, but this past month it hit 63 percent.

I’m also facing a comment-spam problem here at bit-player.org. Because I’ll be traveling in the next few days, I’ve turned on comment moderation. Sorry for the inconvenience, but I think it’s better than hundreds of messages promoting online casinos.

Finally, just to show I haven’t lost my sense of humor about all this, I want to mention a phishing email I received this morning. It purports to be a ticket confirmation from Delta Air Lines, with a zipped attachment that’s doubtless something nasty. How do I know it’s a fake? Because of this passage in the body of the letter:

On board you will be offered:

- beverages;

- food;

- daily press.

You are guaranteed top-quality services and attention on the part of our benevolent personnel.

Sent by someone who hasn’t flown lately.