Sunday, September 22, 2019

Algorithms by Jeff Erickson: a very short review

I recently followed a link from somewhere to Professor Jeff Erickson's algorithms web site. Erickson, who has been a professor at the University of Illinois for 20 years, maintains a wonderful textbook simply entitled Algorithms.

Although you can read the entire book (and many additional supplements) online, I splurged and got the paper copy, because it was easier to read on my commute.

The biggest advantage of the paper copy, besides that I can read it on my commute where it's easier to read printed material than to bring up my computer, is that it's inexpensive. Most other modern algorithms textbooks nowadays are roughly five times the price of Erickson's book.

The biggest disadvantage of the paper copy is that it is in black-and-white, so the marvelous multi-color diagrams from the online book are rendered in a sort of gray-scale. But the diagrams are carefully-enough built that you can understand them even without the color coding, and if you're really stuck on one you can go online and look at just that one diagram.

Anyway, bottom line: I really like Erickson's book. His writing style is clear and engaging (for a computer science textbook, that is!); he includes a very nice selection of modern, relevant, important algorithms, with plenty of pointers to further areas for the interested reader (many of which are also online at Erickson's site); and the exercises at the end of each chapter are very useful for practicing the techniques that have just been discussed.

Bonus links: if you find Erickson's book hard going because you're a bit out of date on some of the fundamentals, Erickson kindly links to two other great sites: Professor Margaret Fleck's Building Blocks for Theoretical Computer Science, and Lehman, Leighton, and Meyer's Mathematics for Computer Science.

Now, all I need is more time to read.

Saturday, September 21, 2019

Up, up, and away

Big news here at the East Cut: Malcolm Drilling have removed the amazing Liebherr 873 mobile crane which supported their 30-month sub-project of deep-foundation work at the Oceanwide Center.

They took that crane away overnight! Monday at 4:00 PM, it was there. Tuesday at 7:30 AM, it was not. Check the link above for the sketch of what was involved in disassembling and removing it. Boy I wish I had known to be there to watch. Sigh.

Now the project changes from building down, to building up.

Things have been a bit challenging for the Oceanwide Center project. Oceanwide is a Chinese developer, and the trade war and global economic conditions have greatly complicated things. They have halted work on the partially-completed Oceanwide Plaza in Los Angeles, but the San Francisco project is still underway, it seems.

At least, there are still crews on the site in San Francisco, and a new pedestal crane was recently installed, so I think they are still moving forward.

Time will tell, I guess.

I hope that the building gets built, because we are out of room across the street and we need new office space!

Sez the Chron:

The dearth of space and continued demand from the tech industry has led to leases for future buildings that haven’t even been approved by the city, such as Salesforce’s lease at 564 Howard St. and Pinterest’s deal at 88 Bluxome St.

The 564 Howard Street site, if it gets built, will connect directly to the Salesforce Park:

The site known as Transbay Parcel F is a dirt lot. In five years, the site at 564 Howard St. is set to become a soaring 800-foot glass high-rise with space for 1,500 workers, along with 165 condos and 190 hotel rooms.

If it gets built.

I have this feeling that growth is slowing rapidly across the country, and very specifically in the tech industry, as the impending recession begins to be felt everywhere. Tech is still an enormous generator of economic activity, but the global conditions are worsening fast.

So I think all these plans from three years ago are being frantically re-thought.

Meanwhile, since across the street means the Salesforce Tower, the tallest building west of Mississippi (by some measures), you should take some time to look at this gorgeous portfolio of pictures taken by photographer Gary Leonard during the topping out of the Wilshire Grand Hotel 3 years ago.

I found Leonard's photos via this nice short Snopes article that's making the rounds right now.

Onwards and upwards!

Sunday, September 15, 2019

Some music I've been listening to...

... somewhat ranked. Sorta.

  • Local Natives: Sunlit Youth. I can't believe this band isn't getting more attention. They burst onto the scene with Gorilla Manor in 2010, followed up with Hummingbird in 2013, then Sunlit Youth in 2016, and this summer they released Violet Street.

    Every one of these albums is wonderful, but Sunlit Youth is somehow my personal favorite. I've gotta figure out a way to see them live, but their 2019 tour didn't come anywhere close to my part of the world, sigh.

  • Sufjan Stevens: Carrie & Lowell. This is probably the most heart-breakingly perfect 40 minutes of music you will ever hear. Honest, intimate, tragic, compelling, unforgettable: all of these apply to Carrie & Lowell, an album which largely consists of Stevens trying to come to grips with his feelings about his mother and her premature death.

    The only hesitation I have about this album is that, each time I play it, there is a recovery period. I have to rest, and contemplate, and reflect.

  • Lord Huron: Vide Noir. What is it about Michigan's Ben Schneider that is so compelling to me? I'm not sure, but he certainly has me hooked. Lonesome Dreams was marvelous, Strange Trails just as good, and Vide Noir builds on those successes to find something richer and more nuanced. He can somehow capture the essence of sitting around the campfire, listening to stories told by those wandering cowboys of yore.
  • Lumineers: III.


    I've been a Lumineers super-fan since their break-out debut in 2011, and, like everyone else in the world, I've been waiting eagerly for III since it was announced last winter.

    But, when it finally arrived, it just blew my mind. With III, they have taken their phenomenal musicianship and married it with a deep and introspective voyage into their souls.

    I suspect that there will be many people who find III to be the wrong album for them.

    But for me, I'm thrilled.

  • Joseph: Good Luck, Kid. Since their monster self-titled debut in 2016, Joseph have been near the top of my Bands To Watch. It was going to be very, very hard for them to top that debut album, but Good Luck, Kid is very, very good.
  • Dave Matthews Band: Come Tomorrow. For nearly 30 years, The Dave Matthews Band has been producing magnificent work. Even if Come Tomorrow isn't their strongest album ever, it's been good enough for at least 2 dozen listens this summer.
  • Elephant Revival: Break In The Clouds. I, sadly, had the bad luck to stumble upon Elephant Revival just as the band had decided to call it quits and go their separate ways; life got in the way, I guess? This is an enchanting band, nicely incorporating bluegrass, jazz, and folk influences into a lovely ensemble. I've only listened to half of the music that they managed to record during 10 lovely years. Why, oh why didn't I learn about them years ago?
  • Gregory Alan Isakov: The Weatherman. Oh, everybody knows about Isakov, I'm not telling you anything you haven't already heard elsewhere. Can a musician be both dependable and revealing simultaneously? Everybody compares him to Van Morrison, which is a bit audacious because he isn't quite there, yet. Yet.
  • Billie Eilish: WHEN WE ALL FALL ASLEEP, WHERE DO WE GO?. A little bit funky, a little bit smooth. A little bit edgy, a little bit elegant. But really: how can a 17-year-old possibly be this good already? Where will she go from here?
  • Tame Impala: Innerspeaker. I actually got both Innerspeaker and Lonerism this summer, and, honestly, I can't tell which one I prefer. They're both atmospheric and fascinating. Tame Impala are some sort of blend of The Beatles and Pink Floyd. I guess. Or something.
  • Whitney: Forever Turned Around. Whitney were another band whose debut album just captivated me. Light Upon The Lake was a collection of hook after hook, sing-along-lyrics ("I wanna drive around/with you with the windows down/and we can run all night"), and some sort of energy that just grabbed me.

    So my expectations for album number 2 were a bit too high. Still, Forever Turned Around is growing on me. So I keep moving it up and down in my Summer 2019 list.

  • Nathaniel Rateliff and the Night Sweats: Tearing at the Seams. I love the term, "rock and soul". Rateliff is full of energy and emotion and heat. Lots and lots of heat. GREAT driving music.
  • Shakey Graves: Can't Wake up. Again, this is a sophomore effort, after his very promising And The War Came. I really like this album, but I feel like Shakey Graves still hasn't produced his best work, and I wonder if he somehow needs something to challenge him.
  • Brett Dennen: Smoke and Mirrors. This is a strong work by Dennen, who has found his groove and delivers a lovely album here.
  • Young the Giant: Home of the Strange. "Cough Syrup", the stratospheric hit from Young the Giant's debut album, was such a wonder-song that it is no surprise that whatever happened next was a bit of a letdown. I skipped Mind Over Matter and went straight to their 3rd CD. And now I'm confused. What will happen next?
  • Indigo Girls live with the Colorado Symphony Orchestra. If you're a super-fan, like I am, this is lovely stuff. I need to catch up with their more recent music. But, every time I think about that, I just go put on Strange Fire or Rites of Passage, and I remember when they changed the world.
  • Better Oblivion Community Center. Conor Oberst loves to go make music with other musicians. Phoebe Bridgers is a HUGE talent who is just getting started. I think it was a good experience for her to perform with him, but she's going to make much better music in the future.
  • Santana: Africa Speaks. WTF? Well, it's not boring. Half the tracks I was fascinated by; the other half I couldn't hit "next track" fast enough.
  • Bruce Springsteen: Western Stars. Urk, what? Somebody told me that his daughter is going through a "horse phase". I guess that maybe explains this? Darkness on the Edge of Town this sure ain't.

Thursday, September 12, 2019

Backpacking 2019: Ansel Adams Wilderness

It can be complicated to get the schedules of 6 different people to line up properly, so this year it turned out to be mid-September before we were able to head out on the trail.

But line up the schedules did, and so off we went!

The Ansel Adams Wilderness is a large region of the Sierra Nevada, sharing a boundary with Yosemite National Park on its north, a second boundary with the Devil's Postpile National Monument on its east, and still another boundary with the John Muir Wilderness on its south and east. The Ansel Adams Wilderness is also fascinating to backpackers because it has significant trailhead access on both the east and west sides of the Sierra Nevada.

I often refer to this part of the world as "the Heart of the Sierra", as it's full of 12,000+ foot mountains, glacier-carved valleys, pristine mountain lakes, majestic canyons with rushing waterfalls and roaring rivers: just the ticket for a perfect vacation hike!

The Ansel Adams Wilderness was originally called the Minarets Wilderness, after the sawtooth formations on the Ritter Range, which maybe you can (barely) see in this picture.

To get to the Fernandez Trailhead on the west side of the Ansel Adams Wilderness from the Bay Area, you've got a journey that breaks down into two parts.

  1. First, you zoom along on 200 miles of high speed roads from San Francisco to Oakhurst; this takes you about 3 hours.
  2. Then, you drive up past Bass Lake until you find Beasore Road, also known as the Sierra Vista Scenic Byway. (Who knew there were 50+ such National Scenic Byways in California?) This 30 miles of road will take you from elevation 2,000 feet up to elevation 7,500 feet, and will also take you about 2 hours. It's good to slow down and enjoy the road, but you should also take this into account in your planning!

In what might be a first for me, the driving directions in my 2016 printing of Sierra South were incorrect, and we ended up driving to the Norris Trailhead first, then realizing that we were at the wrong trailhead, then retracing our steps back to Beasore Road, then proceeding about 100 yards further down the road, then we found the road to the Fernandez Trailhead. I think that, perhaps, the road to the Norris Trailhead has changed since the book was written, and I just wasn't paying quite enough attention to the (faded) Forest Service road signs. It was but a momentary diversion, though.

To its credit, my Tom Harrison map of the Ansel Adams Wilderness showed the road clearly (I just didn't look at that part of the map closely until I'd already made the mistake, duh!)

Our hike from Fernandez Trailhead up to Vandeburg Lake was a straightforward climb of about 1200 vertical feet over about 4.5 miles of trail. Fatiguing, especially at 8,000 feet of elevation, but the trail was well-maintained and well-marked.

We had originally been intending to make it all the way to Lady Lake, but by the time we arrived at Vandeburg Lake it was already 4 PM, and there was a lovely existing campsite that matched our group size perfectly, so we declared victory.

We visited Lady Lake the next day, as well as visiting the Staniford lakes which were quite delightful.

One of the advantages of going backpacking after Labor Day is that the Sierra summer backpacking season is over, and so you (mostly) have the trails and campsites to yourself.

Another of the advantages of going backpacking at the end of the summer is that it is the driest part of the year, so the trails are clear and dry (if a bit dusty), the water crossings are generally not intimidating, and, to a first approximation, there are no mosquitoes!

Unfortunately, one of the downsides of it being the driest part of the year is that most of the mountain wildflowers had already disappeared for the year.

More importantly, another of the disadvantages of going backpacking in mid-September is that summer is almost over, and it is starting to get COLD! During our trip, the high temperatures were only in the mid-60's and low-70's, and the overnight lows were down in the low 30's.

There were even some snow fields within distance of the lake, so we had a snowball fight and I built a snowman.

I was glad that I had my nice new sleeping bag, rated for 15 degrees and true to its word.

Yet another disadvantage, which rather took us by surprise, is that late summer, particularly after a long wet winter, is apparently peak season for yellow jackets and other types of wasps. Each day, in the early afternoon, we found ourselves being annoyed and chased about by small swarms of these aggressive and very annoying insects. One of our party was stung twice, including once on his tongue (!), and had to have our "wilderness nurse" remove the stinger with a trusty pair of tweezers.

The UC Davis website has a lot of useful background information about these wasps,

But these are just the ups and downs of backpacking trips, I guess, and for the most part our trip was lovely.

The lakes were lovely.

The views were astounding.

Our intrepid fisherman, Rich, caught a fish! It was, I think, a rainbow trout? I don't know much about fish identification but maybe this was a Kern River Rainbow Trout? It certainly seemed much more like a Rainbow Trout than a Brown Trout, even though I think Brown Trout is typically what you find in these parts?

All in all, it was a wonderful trip.

Monday, September 2, 2019

1491: A very short review

Charles Mann would certainly be the first to admit that 1491: New Revelations of the Americas Before Columbus is now getting "old".

It was published 15 years ago, after all, and even though Mann has revised it a tad, that's a significant period of time, and the revelations are certainly no longer new.

With a (slightly) deeper interpretation, however, one of Mann's major points is that books such of these are of necessity always old, even the moment after they are written:

Meanwhile, new disciplines and new technologies were creating new ways to examine the past. Demography, climatology, epidemiology, economics, botany, and palynology (pollen analysis); molecular and evolutionary biology; carbon-14 dating, ice-core sampling, satellite photograph, and soil assays; genetic microsatellite analysis and virtual 3-D fly-throughs -- a torrent of novel perspectives and techniques cascaded into use. And when these were employed, the idea that the only human occupants of one-third of the earth's surface had changed little for thousands of years began to seem implausible. To be sure, some researches have vigorously attacked the new findings as wild exaggerations. ("We have simply replaced the old myth [of untouched wilderness] with a new one," scoffed geographer Thomas Vale, " the myth of the humanized landscape.") But after several decades of discovery and debate, a new picture of the Americas and their original inhabitants is emerging.

When I started reading 1491, I had no idea what genetic microsatellite analysis was, and I had to look it up (this is a pretty approachable overview), but 1491 isn't really a book about how anthropologists, historians, and other similar disciplines operate.

Rather, it's (at least) two other books:

  • It's a lively and entertaining look at what we currently know about what the Americas were when the enormous waves of immigration from Renaissance Europe began in the late 1400's
  • But it's also an attempt to help you, the reader, become a better consumer of the information you receive about how we got to this point, how the world is changing, and what it might mean for what you think you know.

Much of 1491 flies by, Mann leads us at a frenetic pace through much memorable history:

Dazzled as he was, Cortes was also aware that with a single command Motecuhzoma could order his army "to obliterate all memory of us." The Spaniards counteracted this thread by inventing a pretext to seize the tlatoani in his own palace, making him first their captive and then their puppet.

In both Europe and Mesoamerica kings ruled by the dispensation of the heavens. The Mexica reacted to the sacrilegious abduction of their leader with the same baffled horror with which Europeans later reacted to Cromwell's execution of Charles I in 1649. Not wanting to act in a way that could result in Motecuhzoma's death, the Mexica took seven months to mount a counterattack. Fearing the worst, the debased tlatoani made a begging public appearance on behalf of the Spanish. He soon died, either murdered by the Spaniards (according to Mexica accounts) or slain by his own countrymen (as Spanish chronicles tell it). Soon after came the long-delayed assault. Under the leadership of a vigorous new tlatoani, Cuitlahuac, the Indians force the invaders into narrow alleys where horses were of little advantage. Under a pitiless hail of spears, darts, and arrows, Cortes and his men retreated down the long causeways that linked the island city to the mainland. In a single brutal night the Mexica utterly vanquished Cortes, killing three-quarters of his men. Although the Alliance destroyed causeways in front of the Spaniards, the remnants of the invaders were able to cross the gaps because they were so choked with the dead that the men could walk on the bodies of their countrymen. Because the Mexica did not view the goal of warfare as wiping out enemies to the last man, they did not hunt down the last Spaniards. A costly mistake: Cortes was among the escapees.

A man of unfathomable determination, Cortes never thought of giving up. He persuaded several other vassal states to join his anti-Alliance alliance with Tlaxcala. Negotiating furiously, he assembled a force of as many as 200,000 men and built thirteen big ships in an audacious plan to assault Tenochtitlan from the water.


When Cortes and his Indian allies finally attacked, the Mexica resisted so fiercely despite their weakness that the siege has often been described as the costliest battle in history -- casualty estimates range up to 100,000.

Yet, I suspect that Mann began his book fascinated by the first topic, and set out to write that "first book," but along the way he became even more fascinated by how challenging it is to avoid thinking that we now know everything there is to know about the past, and so he ended up writing that "second book" as well, trying to open our eyes to just how little we know, and just how alert we should be to the possibility that what we think we know, we do not in fact know at all:

At first he did nothing about his observation. Historical demography was not supposed to be his field. Six years later, in 1959, he surveyed more archives in Hermosilla and found the same disparity. By this point he had almost finished his doctorate at Cornell and had been selected for Holmberg's project. The choice was almost haphazard: Dobyns had never been to Peru.

Peru, Dobyns learned, was one of the world's cultural wellsprings, a place as important to the human saga as the Fertile Crescent. Yet the area's significance had been scarcely appreciated outside the Andes, partly because the Spaniards so thoroughly ravaged Inka culture, and partly because the Inka themselves, wanting to puff up their own importance, had actively concealed the glories of the cultures before them. Incredibly, the first full history of the fall of the Inka empire did not appear until more than three hundred years after the events in chronicled: William H Prescott's History of the Conquest of Peru, published in 1847.

Read 1491 because it's wildly entertaining and endlessly engrossing.

But remember 1491 because it makes you a better reader, and a better thinker, in general.

One way or another, however, read 1491.

Monday, August 26, 2019

Updates from The Ocean Cleanup Project

Boyan Slat and the team at The Ocean Cleanup Project are working along, tinkering and learning.

Here's their latest report: Into the Twilight Zone

First, they remind us where they were a year ago:

Our first attempt at doing so was deployed last year: System 001, also known as Wilson. After months of testing, we took Wilson back to port in the first days of this year after it suffered a fatigue fracture. This was not ideal, but both the diagnosis and solution came quite easily.

And then, they bring us up to date on where they are now:

The more complicated challenge was the system’s inability to retain plastic; instead of consistently going faster than the plastic, it alternated between going faster and going slower than the plastic. This meant plastic would float into the system, as planned, but then float out again.


We launched System 001/B in late June, which was followed by a six-week testing campaign to test slowing down the system using a parachute anchor and test speeding up the system using large inflatable buoys.


the winning concept is the slow-down approach, in which we use a parachute anchor to slow down the system as much as possible, allowing the natural winds and waves to push the plastic into the system.


there’s always a twist in each episode; well, here’s ours: the plastic is currently able to cross over the cork line into The Twilight Zone. While it is technically still within the boundaries of the system, there is no screen underneath the floater pipe, so we cannot consider this plastic caught because it is not securely retained in front of the screen.


we will now be using three rows of 32 cm floats stacked on top of each other, creating a total height of about half a meter.

It's a wonderful article, with great diagrams and deeper explanations throughout.

This is incremental engineering at its best: start with something; it does some things properly but fails in other ways; test, improve, repeat.

I'm looking forward to more great updates!

Sunday, August 25, 2019


I was completely enthralled by Scrappers: The Big Business of Scavenging in PostIndustrial America.

Hypnarowski later told me that his company, New Enterprise Stone and Lime, also owned some of the land where Bethlehem Steel once existed. The steel mills had been scrapped long ago, but there were still nuggets to be had — or “buttons” to be precise. Buttons are essentially giant metal boulders that weigh as much as 20 tons. When the mills were still operating, iron ore was melted and poured into great big ladles, at which point the less desirable slag would form at the bottom. This slag was then dumped onto Lake Erie’s shoreline, where it hardened and formed buttons. Together, Hypnarowski and Levin worked to salvage these buttons from the lakeside. They had, it seemed, thought of every conceivable way to mine big scrap. Over time, scrappers have remade Buffalo’s landscape. The city has survived, in part, by devouring itself.

Back when steel mills first closed, Lou Jean Fleron, an emeritus professor at Cornell’s school of industrial and labor relations, ran a series of educational programs for the workers who had been laid off. She got close with the families that became destitute. It was a very hard time, she recalled, and whenever she visited Buffalo’s waterfront, her eyes inevitably drifted toward the derelict mills. “Oh, God, it was like a ghost town — like a skeleton — a big, massive black skeleton,” she recalled. Then the demolition crews and the scrappers arrived to do their work. Now when Fleron goes down to the waterfront, she sees young families with their children having birthday parties. The scene is almost pastoral.

“It was important to take it all down,” Fleron told me. “It does make some of the pain go away.”

The hero of the story is the incredibly hard-working Adrian Paisley:

Paisley typically takes scrap from his piles and moves it inside his garage, where he processes it. This is where Paisley makes his money, by extracting the most valuable nuggets. The air-conditioner that he found, for example, was promising because it contained copper tubing, copper wiring and an ACR (an aluminum-copper radiator). The scrapyard might pay him only $4 to $6 for the air-conditioner in its current form, but if he processed it and removed the copper, he might earn three times as much. For this reason, Paisley spends much of his day surgically removing the most valuable metals. He even removes each screw and sells them together in bulk. Scrapyards are willing to pay a premium for scrap like this because it saves them the trouble of having to process it themselves.

It was great to read of Paisley's dream of one day no longer having to do this back-breaking work:

It was all crystal clear in his mind: “I want to see the fog hovering across the ground on a nice cool fall morning. And I don’t want to hear nothing but the birds, and the insects chirping. I want to stand there, man, and drink my coffee and look at the fog. Peaceful.

Amen, Mr. Paisley.

Saturday, August 24, 2019

This. Also, that.

School has started, here in the Bay Area.

Naturally, I have the sniffles, a scratchy throat, and a sinus headache.

Must. Sleep.

But, in the meantime, there's so much to read!

  • What is Haberman?
    I’d never heard of “Haberman” before. The name of the neighborhood that people who live here would recognize is Maspeth (which you can see up-and-to-the-right of Haberman). Is Haberman even a real neighborhood? Why did Google put this giant Haberman label on the map?
  • The Pin Is Mightier: Why it’s so satisfying to find—and make—fake locations in Google Maps.
    It’s chaos that Google appears hard-pressed to stop. In a June 2019 blog post, the company says it took down 3 million fake business profiles in 2018, around 85 percent of which were flagged by internal systems, and 90 percent of which were removed before users could see them. Google did not provide statistics on how many new businesses get added a year, or how many listings appear on Google Maps, but given that the service includes data from 220 countries, 3 million listings is likely a drop in the bucket. A Google spokesperson says the company has a team dedicated to Maps fraud, and has “strict policies in place” to detect fraud through “manual and automated systems,” but declined to reveal further details “so as not to tip off spammer or others with bad intent.”
  • Algorithms, by Jeff Erickson
    This web page contains a free electronic version of my self-published textbook Algorithms, along with other lecture notes I have written for various theoretical computer science classes at the University of Illinois, Urbana-Champaign since 1998.
  • Highlights from Git 2.23
    The open source Git project just released Git 2.23 with features and bug fixes from over 77 contributors, 26 of them new. Here’s our look at some of the most exciting features and changes introduced since Git 2.22.
  • Hiring is Broken: What Do Developers SayAbout Technical Interviews?
    Posters report that these interviews cause unnecessary anxiety and frustration, requiring them to learn arbitrary, implicit, and obscure norms. The findings from our study inform inclusive hiring guidelines for technical interviews, such as collaborative problem-solving sessions.
  • Tech Interview Handbook: Carefully curated content to help you ace your next technical interview
    The Tech Interview Handbook contains carefully curated content to help you ace your next technical interview with a focus on algorithms. While there are a ton of interview resources on the internet, the best ones are either not free, or they do not cover the complete interview process, usually only focusing on algorithms.
  • How to Build Good Software
    Some core operating principles that can dramatically improve the chances of success:
    1. Start as simple as possible;
    2. Seek out problems and iterate; and
    3. Hire the best engineers you can.
    While there are many subtler factors to consider, these principles form a foundation that lets you get started building good software.
  • Every productivity thought I've ever had, as concisely as possible
    I combed through several years of my private notes and through everything I published on productivity before and tried to summarize all of it in this post.
  • They Get Fired All the Time. And They Have No Idea Why.
    Through weeks of intensive research, a singular truth emerged. People with Asperger’s syndrome, the term still commonly used for one of the most well-known forms of autism spectrum disorder, bring serious advantages to the financial markets: extreme focus, a facility with numbers, a willingness to consider unpopular opinions, a strong sense of logic, and an intense belief in fairness and justice. But, like other autistic employees, they often feel alienated from their managers, colleagues, and clients. Sometimes they simply get fired.
  • A Walk In Hong Kong
    All that prelude is to say, coming in to the Hong Kong protests from a less developed country like the United States is disorienting. If you have never visited one of the Zeroth World cities of Asia, like Taipei or Singapore, it can be hard to convey their mix of high density, mazelike design, utterly reliable public services, and high social cohesion, any more than it was possible for me or my parents to imagine a real American city, no matter how many movies we saw. And then to have to write about protests on top of it!
  • WeWTF
    In frothy markets, it's easy to enter into a consensual hallucination, with investors and markets, that you’re creating value. And it’s easy to wallpaper over the shortcomings of the business with a bull market's halcyon: cheap capital. WeWork has brought new meaning to the word wallpaper.

Wednesday, August 21, 2019

Weird ... what happened to the Forest Service website?

I can't get to any link for the United States Forest Service websites anymore.

All the various ranger stations, forest service campgrounds, etc., used to be at website addresses, but now all the web browsers just say:’s server IP address could not be found.

Somebody messed up a DNS record somewhere and thousands of web pages vanished?

For example, go here and try clicking on any of the Geo-enabled PDFs in the "Topographic Maps" section.

Monday, August 12, 2019

Up, up, and away

Yesterday they welcomed buses back to the TransBay Bus Terminal, aka Salesforce Park.

Here's a nice story in Wired with lots of pictures and fascinating details: How 'Microcracks' Undermined San Francisco's New Bus Terminal

the construction process involved cutting away 8 inches of the flange right where it needed to be strongest. “The problem was the geometry of the weld access hole,” Frank says. “It has this corner on it, and it acts as a stress concentrator.”

The holes weren’t circular—they were rectangular, with rounded edges. And those corners, probably cut with a plasma cutter, acquired “microcracks” just a few hundredths of an inch deep. The investigators know they were cut with something hot, because the surfaces of the cracks were coated with a colored deposit, an oxide that could only have resulted from exposure to high heat. “You can actually see it,” Vecchio says. “It’s a very deep red, as opposed to what regular rusting of steel looks like, which is going to be more orange in color.”

Much of this story has been told before, but the Wired article is well-written and has some great pictures from the forensic studies of the failed girder.

Some bits are quite new to me:

The ability of something—steel, in this case—to resist fracture after it cracks is called “fracture toughness.” It’s measured with what’s called a Charpy impact test, basically a very precise banging on the metal until it breaks. According to spec, the steel in the Transbay Terminal was supposed to absorb 20 foot-pounds of energy before it fractured at room temperature. It did, but testing by LPI showed lower toughness deeper inside the steel. That’s where the pop-in cracks formed

And this new information appears to suggest an explanation for one of the most tantalizing questions: why did the beams fail in one part of the structure, but not in another very similar part:

That may also explain why the girders over Fremont Street cracked, but the ones over First Street did not. “The difference was the sequence of construction,” Engelhardt says. “On First Street, the welds were made first, and the holes were made after. On Fremont Street, the holes were made first. That turned out to be the decisive difference.”

This morning, the buses were again running in the terminal.

Let's hope things continue to work well now.

Thursday, August 1, 2019

Stuff I'm reading, mid-summer edition

Here you go, stuff you might or might not find interesting, too.

  • DMV Strike Team Final Report
    the DMV is facing historic and unprecedented surges in demand. This increased demand has been primarily driven by the following:
    • Stringent federal identification requirements to obtain a REAL ID, which require an in-person visit to a DMV field office.
    • Motor Voter opt-out requirements, which have greatly increased the workload of DMV staff.
    The Strike Team focused its efforts on improving the processes surrounding REAL ID, with the expectation that increased efficiencies in REAL ID transactions would then translate to other areas of the DMV.

    It is clear that changes are essential if the DMV is to meet its most immediate challenge: successfully meeting increased demand for REAL ID driver licenses before the October 1, 2020 federal deadline

  • The Best Refactoring You've Never Heard Of
    We did a four step process to go from the recursive to the iterative version. First, we made it CPS so these functions appeared. And then we defunctionalized those functions. So now we have these two mutually recursive functions passing around this continuation object. We inlined one to the other. Now it's tail recursive; it becomes a loop. But, of course, the inlining is just kind of moving things around, so we can do the tail-recursion elimination. The big insight that made this all possible, the real workhorse of this transformation, was to defunctionalize the continuation!
  • Cryptographic Attacks: A Guide for the Perplexed
    Over the years, the landscape of cryptographic attacks has become a kudzu plant of flashy logos, formula-dense whitepapers and a general gloomy feeling that everything is broken. But in truth, many of the attacks revolve around the same few unifying principles, and many of the interminable pages of formulas have a bottom line that doesn’t require a PhD to understand.
  • Operating a Large, Distributed System in a Reliable Way: Practices I Learned
    This post is the collection of the practices I've found useful to reliably operate a large system at Uber, while working here. My experience is not unique - people working on similar sized systems go through a similar journey. I've talked with engineers at Google, Facebook, and Netflix, who shared similar experiences and solutions. Many of the ideas and processes listed here should apply to systems of similar scale, regardless of running on own data centers (like Uber mostly does) or on the cloud (where Uber sometimes scales to). However, the practices might be an overkill for smaller or less mission-critical systems.
  • Distributed Locks are Dead; Long Live Distributed Locks!
    For the impatient reader, here are the takeaways of this blog post:
    • FencedLock is a linearizable distributed implementation of the java.util.concurrent.locks.Lock interface with well-defined execution and failure semantics. It can be used for both coarse-grained and fine-grained locking.
    • FencedLock replicates its state over a group of Hazelcast members via the Raft consensus algorithm. It is not vulnerable to split-brain problems.
    • FencedLock tracks liveness of lock holders via a session mechanism that works in a unified manner for both Hazelcast servers and clients.
    • FencedLock allows 3rd-party systems to participate in the locking protocol and achieve mutual exclusion for the side-effects performed on them. This is the “fenced” part of the story.
    • FencedLock is battle-tested with an extensive Jepsen test suite. We have been testing its non-reentrant and reentrant behavior, as well as the monotonicity of the fencing tokens. To the best of our knowledge, FencedLock is the first open source distributed lock implementation that is tested with such a comprehensive approach.
  • Making Containers More Isolated: An Overview of Sandboxed Container Technologies
    The main difference between a virtual machine (VM) and a container is that the VM is a hardware-level virtualization and a container is a OS-level virtualization. VM hypervisor emulates a hardware environment for each VM, where the container runtime emulates an operating system for each container. VMs share the host’s physical hardware and containers share both the hardware and the host’s OS kernel. Because containers share more resources from the host, their usages of storage, memory, and CPU cycles are all much more efficient than a VM. However, the downside of more sharing is the weaker trust boundary between the containers and the host.
  • Testing the CP Subsystem with Jepsen
    Running a Jepsen test on a distributed database is like sneaking up on Superman with kryptonite while he is trying to overcome his biggest challenge. Jepsen subjects the database to various system failures while running a test case and checks whether the database is able to maintain its consistency promises. It can create chaos in many ways: make a single node or multiple nodes crash or hiccup, partition the network, or even make clocks go crazy.
  • BPF Performance Tools
    This is the official site for the book BPF Performance Tools: Linux System and Application Observability, published by Addison Wesley (2019). This book can help you get the most out of your systems and applications, helping you improve performance, reduce costs, and solve software issues. Here I'll describe the book, link to related content, and list errata.
  • Why the dockless scooter industry is going after a repossessor and a bike shop owner
    On July 1st, the City of San Diego implemented new regulations to address the scooter complaints. The regulations will require scooter companies to obtain insurance policies, free the city from all legal liability, cap speeds on the boardwalk, and obtain permits for every scooter in circulation. It’s still too early to tell whether the new regulations will make a difference.

    “We are aware that people are still riding on sidewalks, we are aware that people are colliding into people and then taking off,” San Diego Police Department Lt. Shawn Takeuchi says.

  • The Near Impossible 20-Year Journey to Translate 'Fire Emblem: Thracia 776'
    Take one common problem with fan localizations: the sheer efficiency of Japanese. You can say a lot more with fewer characters in Japanese than English. Naturally, the game’s dialogue boxes were specifically programmed with Japanese in mind, not English. When a localizer drops the dialogue translated into English, there A) might not be space for the dialogue to fit, and B) if you go over the programmed character limit, the game could crash.
  • One giant ... lie? Why so many people still think the moon landings were faked
    t took 400,000 Nasa employees and contractors to put Neil Armstrong and Buzz Aldrin on the moon in 1969 – but only one man to spread the idea that it was all a hoax. His name was Bill Kaysing.
  • The 100 Best Movies of the Decade
    Cinema is in a constant state of flux, but it’s never mutated faster or more restlessly than it has over the last 10 years. And while the decade will no doubt be remembered for the paradigm shifts precipitated by streaming and monolithic superhero movies, hindsight makes it clear that the definition of film itself is exponentially wider now than it was a decade ago. Places. Products. Mirrors. Windows. Reflections of who we are. Visions of who we want to be. A way of capturing reality. A way of changing it. If the most vital work of the 2010s has made one thing clear, it’s that movies have never been more things to more people than they are today. And our week-long celebration list of the Best Films of the 2010s has us more excited than ever about what they might be to you tomorrow.
  • Billie Eilish and the Triumph of the Weird
    Eilish has conquered the music world in part by doing everything she’s not supposed to. Her music is darker and weirder than that of most teen pop stars, with a gothy, punkish, vaguely sinister edge and nary a hint of bubblegum. For her core teen-girl fan base, she’s like the cool senior in art class who dresses and acts the way they wish they could: stylish, outrageous, maybe a little dangerous. (As her hit single “Bad Guy” puts it, “I’m the bad type, make-your-mama-sad type. . . might-seduce-your-dad type.” You get the sense that she’d love to be a “Parents Beware” segment on the 11:00 news.) Her vibe is both semi-nihilist and joyously defiant, a perfect soundtrack for a generation facing a half-dozen existential threats before first period. But she’s also playful, mischievous, vulnerable, alienated, melancholy — in other words, a teen.
  • The Ham of Fate
    What he honed in his Brussels years is the practice of political journalism (and then of politics itself) as Monty Python sketch. He invented a version of the EU as a gigantic Ministry of Silly Walks, in which crazed bureaucrats with huge budgets develop ever more pointlessly complicated gaits. (In the original sketch, the British bureaucrats are trying to keep up with “Le Marché Commun,” the Common Market.) Johnson’s Brussels is a warren of bureaucratic redoubts in which lurk a Ministry of Dangerous Balloons, a Ministry of Tiny Condoms, and a Ministry of Flavorless Crisps. In this theater of the absurd, it never matters whether the stories are true; what matters is that they are ludicrous enough to fly under the radar of credibility and hit the sweet spot where preexisting prejudices are confirmed.

Monday, July 29, 2019

Thinking, Fast and Slow: a very short review

Suppose you were to (somehow? I don't know how to do this) compile a list of all the books written by all the Nobel Prize winners.

And then, exclude the ones written by the winners of the Nobel Prize for Literature, because of course they write a lot of books!

And then, exclude the ones written by the winners of the Nobel Peace Prize, because they write a lot of books, too.

I think at that point you're left with a pretty short list of books.

Of those, you'll find the occasional book written by a Nobel Prize winner in the hard sciences, such as James Watson's The Double Helix, or Murray Gell-Mann's The Quark and the Jaguar, but mostly what you'll find are books written by winners of the Nobel Economics Prize.

Because those economists write a lot of books, too.

And I confess that I haven't read most of those books.

But, occasionally, the Nobel Prize in Economics is awarded to somebody who isn't, strictly speaking, an economist, and Daniel Kahneman is one such. Kahneman, who had a long career as a Professor of Psychology at Princeton, takes the opportunity, with Thinking, Fast and Slow, to describe his conclusions about something that might sound trivial, but is actually quite sophisticated: how do we think?

Not, that is, how we think at some sort of physical level, with neurons and transmitters and the like, but how do we make decisions, how do we come to conclusions, how do we form judgments?

Kahneman's fundamental insight is that there are two different mechanisms at play: fast thinking, which is spontaneous and intuitive; and slow thinking, which is deliberate and effortful. In a rather awkward turn of phrase, he calls these System 1 and System 2:

I adopt terms originally proposed by the psychologists Keith Stanovich and Richard West, and will refer to two systems in the mind, System 1 and System 2.
  • System 1 operates automatically and quickly, with little or no effort and no sense of voluntary control.
  • System 2 allocates attention to the effortful mental activities that demand it, including complex computations. The operations of System 2 are often associated with the subjective experience of agency, choice, and concentration.
The labels of System 1 and System 2 are widely used in psychology, but I go further than most in this book, which you can read as a psychodrama with two characters.

When we think of ourselves, we identify with System 2, the conscious, reasoning self that has beliefs, makes choices, and decides what to think about and what to do. Although System 2 believes itself to be where the action is, the automatic System 1 is the hero of the book. I describe System 1 as effortlessly originating impressions and feelings that are the main sources of the explicit beliefs and deliberate choices of System 2. The automatic operations of System 1 generate surprisingly complex patterns of ideas, but only the slower System 2 can construct thoughts in an orderly series of steps. I also describe circumstances in which System 2 takes over, overruling the freewheeling impulses and associations of System 1. You will be invited to think of the two systems as agents with their individual abilities, limitations, and functions.

And the rest of the book, indeed, in quite readable prose and with very evocative and illuminating examples, explains these notions in considerable detail.

I think you can summarize Kahneman's book pretty reasonably as: usually, you let yourself be driven by hunches and knee-jerk reactions; yet usually, your hunches and intuitions are pretty reliable, especially in areas where you have lots of experience; sometimes, though your best guess is really bad, and you need to be aware that this can happen so that you can guard against it.

I know: that sounds pretty dry. But overall, this isn't a dry book. It's a surprisingly interesting and compelling book!

Saturday, July 27, 2019

Comfort Me with Apples: a very short review

Ruth Reichl's marvelous Comfort Me with Apples: More Adventures at the Table somewhat defies categorization.

It's primarily a memoir, part of a longer series that includes her earlier Tender at the Bone and her later Garlic and Sapphires and Save Me the Plums (none of which I've read).

It's also sort-of a cookbook. At least, there are actual recipes in it (none of which I've tried, although I'm itching to try both her approach to asparagus as well as a peculiar little tidbit she calls "Swiss Pumpkin" which sounds absolutely marvelous but must be made in January).

And it's definitely full of wonderful tales about celebrities of the (1980's) food world: private meals in Alice Waters's house, tagging along with Wolfgang Puck behind the scenes as he prepares to open Chinois on Main, etc.

And does she ever have stories to tell! Exciting stories from her trips around the world, hilarious tales and scandalous gossip from the heady world of California grand cuisine, warm and emotional insights into her family and her personal life, all of it written in a comfortable and appealing style that makes every page fun to read.

What struck me most about Comfort Me with Apples, however, was how vividly it arose from a very specific time and place: California in the late 1970's and early 1980's was very distinctive and awash with change. The Vietnam War was over, the oil crisis had passed, Ronald Reagan was elected president, and people were moving to California by the millions, drawn by the state's natural beauty and booming economy, attracted by visions of surfers and skateboarders and popular TV shows like CHiPs, Hart to Hart, Baywatch, and the like.

Meanwhile Berkeley was (and still is) a very unusual place, full of fervor and protest and change, and Reichl's descriptions of her life there capture the time wonderfully:

Doug wanted to make art, I wanted to write, and we moved to Berkeley so we could live cheaply and not become part of what we called the success machine. We steered clear of the stuff of ordinary existence, the clothes and cars and furniture that other people spent their money on. We chose a communal household on Channing Way because the rent was forty-five dollars a month and we could support ourselves with part-time jobs. I cooked in a restaurant; Doug did carpentry. We bought our clothes in thrift stores, borrowed our books from the library, and thought of a night at the movies as a major treat.

I'm not sure if I'll ever find the time to read Reichl's other books, but I certainly enjoyed every page of Comfort Me with Apples.

Friday, July 26, 2019

Go East, very Far East

I suspect that most people, overwhelmed by the noise and churn of the mass media, don't realize quite what a big deal an announcement like this actually is: Driving Customer Success With Alibaba

today Salesforce announced a strategic partnership with Alibaba, an innovation leader that helps its customers transform the way they market, sell, and operate through businesses like Alibaba Cloud and Tmall. Alibaba will become the exclusive provider of Salesforce to customers in mainland China, Hong Kong, Macau, and Taiwan, and Salesforce will become the exclusive enterprise CRM product suite sold by Alibaba.

Together, Salesforce and Alibaba will bring Salesforce’s #1 CRM platform — including Sales Cloud, Service Cloud, Commerce Cloud, and Salesforce Platform — to customers in mainland China, Hong Kong, Macau, and Taiwan. Alibaba’s advanced, secure infrastructure and knowledge of these markets will empower our global customers with a solution that meets local business needs.

Most Americans, and even many people elsewhere in the world, are completely unaware of how rapidly the world's center of (financial) gravity is shifting, and how, increasingly, there's only one country that matters, in global commerce.

And it isn't the United States of America.

Thursday, July 25, 2019

The Last Equation of Isaac Severy: a very short review

Came my way: The Last Equation of Isaac Severy: A Novel in Clues

It's a mystery novel about the unexpected death of a Cal Tech mathematics professor, the patriarch of a Pasadena family of troubled geniuses, and the various enigmatic characters trying to get hold of the secret-of-a-lifetime for which he died.

Which all has something to do with Chaos Theory.

The novel fails miserably at the whole "it's a mathematical secret which would change the world" business.

But if you can overlook that (a bit of a challenge, since it's the core of the plot), Jacobs is an entertaining writer and she crafts a number of entertaining characters, and there's plenty of good old family drama, with lots of those Uncomfortable Family Secrets Revealed that writers love to use to add spice to their mystery novels.

Definitely a fine book for making the commute fly by.

Saturday, July 20, 2019

More trouble on the I-880 railroad overpass

Large Pothole Opens Up on I-880 in Oakland; Multiple Lanes Blocked

The pothole, over Jackson Street, opened up in the No. 3 lane on southbound I-880, the CHP said, but the Nos. 1 and 2 lanes also were closed for the repair work.

Lane number 3, in this section, is of course the only lane that the Port of Oakland container cargo trucks are allowed to use through that stretch of the highway.

They spent so much time and effort on the section of 880 in downtown Oakland where it crosses the Union Pacific Railroad Tracks. That was an *enormous* engineering project!

It was partly for seismic retrofit and partly for traffic issues; the southbound on-ramp from 5th & Oak onto southbound 880 is well-known as one of the most dangerous on-ramps in the entire California road system.

But that bridge (12 lanes wide in sections!!) is still very troubled.

Not only was there that giant hole in the southbound lanes yesterday, but the northbound section of the bridge is separating at the earthquake expansion joint near the apex of the bridge just by the Laney College parking lot, and 3 of the four northbound lanes have enormous steel plates covering the gap in the expansion joint.

I have no idea how or when this can be solved, but it's certainly a great illustration of just how hard it is to build adequate civil engineering structures, even when you try very very hard.

Of course, one of the huge problems in this area is that this is the only road that the Oakland port container cargo traffic can use, so it bears a *very* heavy burden of constant fully-loaded cargo traffic.

But still, that was all well-known when Caltrans built the bridge.

Anyone know if there's a Caltrans project page which covers the ongoing issues with this bridge?

Saturday, July 13, 2019

Fermat's Last Theorem

Somehow, I happened across a beat-up, weathered copy of Amir Aczel's Fermat's Last Theorem just before a long airplane trip, and so I happily accepted the gift.

Aczel has written a number of "popular mathematics" books; I think this was one of his first books.

Fermat's Last Theorem, of course, is a wonderful topic, and perhaps one of the best topics for a popular mathematics book, starting from its origin story in Pierre de Fermat's notebooks ("I have discovered a truly remarkable proof of this theorem which this margin is too small to contain") to the marvelous work of Andrew Wiles, who was a great source of quotations himself:

Perhaps I could best describe my experience of doing mathematics in terms of entering a dark mansion. You go into the first room and it's dark, completely dark. You stumble around, bumping into the furniture. Gradually, you learn where each piece of furniture is. And finally, after six months or so, you find the light switch and turn it on. Suddenly it's all illuminated and you can see exactly where you were. Then you enter the next dark room...

(Wiles's evocative quote is pretty much a spot-on description of writing computer software, too, by the way.)

Fermat's Last Theorem is only peripherally about Fermat's Last Theorem. The mathematics in this book stops, more or less, at the level that a strong high school student would encounter. Mostly, it is a sort of history-of-science book, about what the process of "doing mathematics" was like in the second half of the twentieth century.

Which is still a pretty interesting thing to read about.

And, really, the world needs more books about mathematics, of any sort, even if they are just books about mathematicians, rather than books about mathematics. It drives me absolutely crazy when I wander into a magazine rack in a store and I pick up a book full of Sudoku puzzles, and, emblazoned on the cover, it says "No mathematics skills needed!" as if that was something to be happy for. (And anyway they are so wrong: logic and deduction are absolutely mathematics skills. Oh well, what can you do?)

But as it turns out, I already knew most of the story of Fermat's Last Theorem, though perhaps I didn't know quite so much about the individual mathematicians at the heart of the story.

The most interesting part of the book for me, because it was a bit of history that I had somehow never learned, was the discussion of two Japanese mathematicians, Yutaka Taniyama, and Goro Shimura, who together formulated something called the Taniyama-Shimura conjecture when they were both just in their mid-20's; the details of the conjecture turned out to be the critical turning point in "cracking" Fermat's Last Theorem.

If none of this is any interest to you, or if you're not a history of mathematics sort, give Fermat's Last Theorem a pass. But if you think you might find it interesting, it's a fun little book, and perfect for a 6 hour cross-country plane flight!

Thursday, July 11, 2019

Variations in the behavior of the default Java maximum heap size

Since the last millennium, Java implementations have always had system-specific behavior for things such as the maximum amount of memory your Java program can use, also known as the "maximum java heap".

Many (most?) JVM implementations support the -Xmx flag, which allows you to specify the maximum heap size.

But if you don't set that flag, what maximum heap size do you get?

Implementations vary widely in this case.

The most commonly-used JVM implementation is the Oracle JDK, whose behavior is documented here:

In particular, see "Table 2-6 Default Maximum Heap Sizes", which shows that the actual value will

  • depend on your operating system platform,
  • on the choice of a 32-bit or 64-bit JVM,
  • and also on the amount of RAM on the machine,
  • BUT will never exceed 2GB.

However, the OpenJDK, ( behaves differently.

With some experimentation, you will find that the Default Maximum Heap Size on an OpenJDK JVM also depends on various variables, but is NOT hard-limited to 2GB, and instead appears to simply use 25% of the RAM on your machine!

I discovered this when I was trying to figure out why we were experiencing extreme memory pressure on a fleet of machines that I manage. It turns out that our administrators had moved us from OracleJDK to OpenJDK on those machines, and our workloads had a bunch of places where we were NOT specifying -Xmx.

For those workloads, each time we spawned a JVM without specifying the maximum heap size, it had (quietly) changed from using up to 2GB of memory, to using up to 25 % of the system memory, and since we routinely spawned 2 such JVMs, half of our system memory was devoted to those 2 JVMs! Since these were quite large machines, having typically 48GB to 64GB of memory, this meant that a very large memory usage change had occurred: instead of 2 JVMs consuming 4GB of RAM total, the 2 JVMs were now consuming 24-32GB of RAM total!

Big machine or small machine, 25% is a lot! Since our machines routinely run thousands of processes, it took me far too long to notice these two processes quietly occupying half the system ram.

So the overall impact was subtle and it took me a LONG time to notice it (many months, sadly), because all that really happened right away was that the workloads ran more slowly, and the machine performance seemed quite poor, and it took me far too long to understand that the reason was that 2 of the 1000+ processes on the machine were suddenly taking half of the memory on the machine.

Unfortunately, this particular behavior does not seem to be documented anywhere (at least, I haven't found the "openjdk documentation for the -Xmx flag"), although since it is open source you can always "use the source, Luke":

I estimate that I lost, over all of 2019 so far, about 1.5 weeks of my life to this particular detail.

But, happily, I finally figured it out!

Monday, July 1, 2019

Up, up and away

SF’s Brand New Gondola Opens July 1st

One of the most fun ways to get to the Salesforce Rooftop Park isn’t via a boring old escalator or elevator, but by a brand new downtown gondola system with a 20-passenger glass cabin which will connect the Mission Square (the new plaza of the Salesforce Tower at Mission and Fremont) to the rooftop park.


Salesforce Park’s grand reopening will be a subdued affair

San Francisco’s new transit structure, which shuttered six weeks after opening following the discovery of two cracked steel beams in September, will reopen to the public July 1. And while bus service won’t recommence until mid- to late-July, the park level, arguably the public’s preferred portion of the $2.2-billion behemoth, will once again be accessible.

But unlike the first opening, the gondola, which whisks people up two stories from the corner of Mission and Fremont, will be in operation.

Saturday, June 29, 2019

Yes, I just keep looking at this picture

It's pretty much the perfect picture.

Few things are as abstract and complex as finance

In America, retirement support is roughly divided into two parts:

  • Pretty much everybody has access to the Social Security system, which provides basic support when you get old or if you become disabled and cannot work. Related to Social Security is Medicare, with similar goals and restrictions.
  • A substantial, but not complete, section of the population also has access to individual retirement accounts, which are intended to provide the bulk of your retirement support.

Put more briefly, retirement support is pretty much up to you.

Your primary tool for providing for your own retirement is, usually, your company's 401K plan, which gives you tax-advantaged access to investments, and can be as good or bad as your company wants it to be.

Some companies have very good 401K plans (I'm lucky enough to work at one such company), while others have pretty bad ones, frankly. Your only choices in this area are to try to encourage your company to have the best plan it can, and to consider your company's plan as part of your considerations when you choose where to work.

But then, once you have access to a company-provided 401K plan, you still have lots of work to do, as modern 401K plans are fiendishly complicated.

And they, periodically, send you notices like this:

The new investment options are collective investment trusts (CITs) or “commingled pools.” The commingled pools will offer you similar investment strategy and risk as the mutual funds they replaced, but the expenses will be lower.

Like mutual funds, a CIT combines the money of many investors who own a share of the pool and/or trust. A fund manager invests assets on behalf of all shareholders in accordance with the pool’s stated investment objectives.

Unlike a mutual fund, a CIT is available to investors only through their workplace savings plans. Because they are not publicly traded, some information (e.g., ticker symbols, CUSIP numbers, and Morningstar ratings) is not available. A CIT is not registered with the Securities and Exchange Commission (SEC). It is generally governed by state banking laws and by federal agencies, such as the Internal Revenue Service and the Department of Labor.


Maybe you go somewhere else to learn about CITs, and you find a little bit more information:

CITs were first introduced in 1927. Early versions of CITs required investor purchases and withdrawals to be processed manually and were valued infrequently, typically only once per calendar quarter, providing investors little access to portfolio and performance data. For this reason, the early adopters of CITs were defined benefit plans.

But starting in 2000, CITs began operating in ways that many believed were more comparable to mutual funds, providing daily valuation and standardized transaction processing, which greatly increased adoption by defined contribution plans. Then, in 2006, the Pension Protection Act provided for a new default investment election for unallocated 401(k) participant assets. These Qualified Default Investment Alternatives (QDIAs) include certain types of “approved” investment strategies and may take the form of managed accounts, target risk funds and target date funds. Many target date funds—the most widely adopted QDIA—are implemented as CITs, and as their assets have grown, so have the assets of CITs generally. Recently, CIT coverage by database vendors such as Morningstar has increased as well, providing additional transparency and reporting capabilities.

CITs have become a popular alternative to mutual funds within qualified retirement plans. Since 2012, CIT use has grown by 56% within DC plans, while the usage of mutual funds has decreased1—a trend that we expect to continue.

Basically, the fact that my company's plan now offers me new investment options which have lower expenses is a Good Thing, but every time I try to learn enough about finance to understand what the heck all these notices and documents are trying to tell me, I feel overwhelmed by the abstraction and complexity of it all.

And, as a mathematician and software engineer, I'm actually pretty good with abstraction and complexity, I think.

Oh, well, on we go.

Tuesday, June 25, 2019

How to spend your June vacation

You're going to be tired after your very long airplane journey.

So you should have some Hand-rolled ice cream.

Or maybe have a cool drink on the patio at Les Crepes

Or even make a day trip to Charlottesville to take in the mountain air

Then, once everything is all set up

And you've had your rehearsal

Then it'll be time to put on your fancy clothes

(Looking good!)

And attend the real ceremony

(Even if your granddaughter finds part of it a little boring)

The end of the ceremony will involve handfasting!

And everyone will be cheering!

And then it's time for the party!

Which means spending time with family

Family, new and old

Three generations!

And spending time with friends

And other traditions, such as the father-daughter dance

And the second line parasol procession

Oh, a wonderful vacation indeed

Tuesday, June 11, 2019

Google have lost my old pictures, I think

It appears that, whatever Google did recently, they have discarded my old pictures that I posted on my blog.

Whatever I did to put my pictures on my blog, they went to something like:

But those images just fail now.


Live by the cloud, die by the cloud.

Sunday, June 9, 2019

Some of this, some of that

The days are long and my mind wanders.

  • An update on Sunday’s service disruption
    Google’s engineering teams detected the issue within seconds, but diagnosis and correction took far longer than our target of a few minutes. Once alerted, engineering teams quickly identified the cause of the network congestion, but the same network congestion which was creating service degradation also slowed the engineering teams’ ability to restore the correct configurations, prolonging the outage. The Google teams were keenly aware that every minute which passed represented another minute of user impact, and brought on additional help to parallelize restoration efforts.
  • Our not-so-magic journey scaling low latency, multi-region services on AWS
    CQRS is seriously good. By isolating out concerns and clearly defining which use cases you want to optimise for, it becomes possible to invest the effort in the most mission-critical services without having to drag along other functionality at the same time.
  • CQRS
    The change that CQRS introduces is to split that conceptual model into separate models for update and display, which it refers to as Command and Query respectively following the vocabulary of CommandQuerySeparation. The rationale is that for many problems, particularly in more complicated domains, having the same conceptual model for commands and queries leads to a more complex model that does neither well.
  • The Labor Movement’s Newest Warriors: Grad Students
    Hannah Kim and Natalia Piland are not your typical labor organizers. Kim, 23, has a bleached mullet, and when we met at a cafe near campus last Friday, she was wearing baggy track pants and chunky dad shoes. Piland, 29, was wearing all black, other than an iridescent fanny pack. Both of them are graduate students at the University of Chicago.

    It’s the final week of classes, but the two women have not been consumed with schoolwork. Instead, they’ve been busy organizing their peers to fight for better work conditions: On Monday, many UChicago graduate students participated in a three-day walkout, refusing to teach or grade papers.

    “What is a way for graduates to actually have power and to actually be able to push what we want our work place to look like?” Piland said. “The union is the only way that seems feasible.”

    These women, both members of Graduate Students United at UChicago, are among the new faces of unionization in America. They’re organizing what were once stable, middle class professions, which have seen wages and benefits erode precisely as positions opened up to women and minority candidates.

  • Learning Chess at 40
    Denise Park, the director of research at the University of Texas’ Center for Vital Longevity, described what was happening to me in unsettling terms. “As you get older, you actually see clear degradation of the brain, even in healthy people. Your frontal cortex gets smaller, your hippocampus—the seat of the memory—shrinks.” My brain volume is atrophying annually, my cortical thickness dropping some 0.5 percent a year.

    Where my daughter’s brain was hungrily forming new neural connections, mine could probably have a used a few new ones. “You don’t want to be pruning synaptic connections, you want to be growing them,” Park told me. My daughter’s brain was trying to efficiently tame the chaos. “For older adults,” Park said, “there’s not nearly enough chaos.”

    Back at the board, there seemed to be plenty of chaos. For one, my daughter tended to gaily hum as she contemplated her moves. Strictly Verboten in a tournament setting, but I did not want to let her think it was affecting me—and it certainly wasn’t as bad as the frenetic trash talking of Washington Square Park chess hustlers. It was the sense of effortlessness that got to me. Where I would carefully ponder the board, she would sweep in with lightning moves. Where I would carefully stick to the scripts I had been taught—“a knight on the rim is dim”—she seemed to be making things up. After what seemed a particularly disastrous move, I would try to play coach for a moment, and ask: Are you sure that’s what you want to do? She would shrug. I would feel a momentary shiver of pity and frustration; “it’s not sticking,” I would think. And then she would deliver some punishing pin on the Queen, or a deft back rank attack I had somehow overlooked. When I made a move, she would often crow: “I knew you were going to do that.”

  • Open Source Game Clones
    This site tries to gather open-source remakes of great old games in one place. If you think that something is missing from the list - please go to our GitHub repository and create an issue or even a pull request!

    Since all these projects are open-source you can help them and make this world a better place. Or at least you can play something to appreciate the effort people put in them.

  • For Remote Communities In Scotland's Outer Hebrides, Mobile Libraries Are A Lifeline
    In Stornoway, the biggest town in Scotland's Outer Hebrides islands, a yellow van sits on a narrow, one-way street. The Gaelic word leabharlann is painted on the front, back and sides, with its English translation, "library," on the front and sides.

    Driver Iain Mackenzie has loaded his books in the van, organized his customers' orders and is preparing for his last run of the week on the island of Lewis and Harris. The 16-year-old van runs three days a week, covering more than 800 miles of rugged roads to deliver books to more than 800 residents.

  • Strawberry farmers open homes for country's sole village of books
    Until recently, the village, just a few kilometres from the picturesque hill stations of Mahabaleshwar and Panchgani, was known for growing the best strawberries in the country. Now, it is a unique ‘village of books’ with 25 villagers having given up a part of their homes to set up open libraries.

    The idea was inspired by the Welsh village of Hay-on-Wye, which is informally known as the ‘town of books’, and has scores of second-hand and antiquarian bookstores. But the Maharashtra government has made the concept their own and expanded its scope. Its Marathi language department’s experts meticulously put together a collection of over 30,000 books organised under various genres. These were then distributed among the home libraries, as well as public places like temples and schools. Each home is allotted books pertaining to one genre and identified with street signs and wall paintings.