A Crash Course on Derivatives

A quick sketch showing the change in a function. This is the basis of the derivative. A quick sketch showing the change in a function. This is the basis of the derivative.

There you are in your introductory physics course. The course requirements say that you have to be in Calculus 101 (it’s probably not called that) in order to enroll in Physics 101. Why? There are two mathematical things you will likely need to know to survive your physics course. You need to understand derivatives and integration (and vectors too – but that’s usually covered in physics also).

But what if your math course hasn’t covered derivatives by the time you need them in physics? Well, that’s what I’m here for. This is your crash course in derivatives (I’ll write about integration later).

Derivatives: All About Change

Suppose you have some function (it doesn’t have to be x vs. y, it could be anything). What if I want to know how this function changes as the variable changes? That’s what the derivative tells you. Let me start with a couple of examples.

There is a car moving and its position in the x-direction can be described by the following function.

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If I plot this function, it looks like this (I am adding two points so that we can look at the change in position).

Sketches Fall 14 key

How does this function change with time? If I take two points (t1 and t2) I can calculate the change in x divided by the change in t. Yes, this would be the slope of the function.

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That gives me the average rate of change of position during the time interval t1 to t2. In physics, we would also call this the average x velocity. In this case, it doesn’t matter what two points I pick on the graph. I will always get a slope of 2.5 m/s (yes, slope and derivatives have units). I could plot the horizontal velocity and it would look like this.

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Ok, that was fairly simple and not that interesting. How about another example? Suppose I have this function for the position of an object in the x-direction?

La te xi t 1

Here is a plot of that function along with some points on the curve.

Sketches Fall 14 key

In this case, the average velocity (the slope) going from point 2 to 3 is different than the average slope going from points 4 to 5. Then how do we make a graph of velocity vs. time? What time would we associate the average velocity with? Probably the only fair thing would be to take two time points and find the slope and then associate the slope with the average of these two points. In fact, this works perfectly with the above function. When you do that, you get the following plot of slope (velocity) vs. time.

Figure 1sdfsdfdeeeee png

That “average time” trick doesn’t always work. However, I can make it almost work if I use very tiny time intervals. In that case, it doesn’t matter which time (beginning, end, middle) is associated with the time. So, tiny time intervals are nice.

What if you use a zero second time interval? Well, you can’t do that. However, you can do some thing close to a zero second interval. You can find the value of the average velocity in the limit as Δt goes to zero seconds. This is in fact what we call a derivative. We can write it as:

La te xi t 1

Yes, that’s not the way mathematicians would define the derivative but I’m ok with that. It shows the important point that the derivative is just a way to express how a function changes.

Example: The Sine Function

You know the sine function right? Remember you met it at that party last year? Ok, since you already know each other suppose that a mass is oscillating back and forth with the following position function.


Now let me plot this along with some points.


Here you can see that by just picking some point (evenly spaced) on the function, I could find the slope between these points. However, there are several instances where this rate of change for these points is not a good representation of the slope of this function. Yes, we can make this better by putting the points much closer together. If I use a time interval of 0.01 seconds, I get the following for the velocity as a function of time.

Figure Sdfsdwee 1 png

Yes, that looks like a cosine function and NO I did not just plot the cosine function. In fact, here is the exact program I used to make this program.

 Derivativesplot 1 py Users Rjallain Projects Python Derivativesplot 1 py

If you don’t understand everything in there, don’t worry. The important part just goes through the points and calculates the slope (the “for i in range.. part”). If you want, you could change the number of points used to calculate the slope – it would be fun.

If I wanted, I could also plot the following function.

La te xi t 1

I would get EXACTLY the same plot as above. So you can see two things. First, the derivative is just the rate the function changes for very tiny time intervals. Second, this derivative can usually be written as another actual mathematical function. In general, we write the derivative as:

La te xi t 1

Here the Δs are replaced with d‘s to indicate that we are looking at the limit as Δt goes to zero. That’s it.

But how do you take a derivative?

Ummm…didn’t I just do that above? Oh, you think it’s cheating to use a computer? Ok, I can understand that. But really, it’s not cheating. A numerical program takes a derivative by using finite (but very tiny) time intervals. In real life, this is always what we are dealing with and science deals with the real world.

But how do you get a mathematical function without using a computer? I’m not going to go over all the details – that’s what your math class is for. All I care about (as a physics coach) is that you understand what a derivative is and how to find it. So, here are some “rules”.

Product rule. You never have just a plain function. They will typically be two smaller functions multiplied (like a*t – even if a is a constant). Suppose I have a function g and f (both are functions of t). Now I have a position function (x(t)) such that:

La te xi t 1

I can find the derivative of this function by finding the derivative of g(t) and f(t) in the following manner.

La te xi t 1

I will use this in an example in a short bit.

Power rule. If you have a polynomial, it’s pretty easy to find the derivative. Suppose I have a function like this:

La te xi t 1

Where n is just a constant. In that case, the derivative of this function will be:

La te xi t 1

Trig functions. Remember, I am not deriving these. I am just telling you “the answer” – so here are derivatives of the two most common trig functions.

La te xi t 1

I cheated – I skipped a small step above. Sorry. In order to really understand the trig derivatives, you also need the chain rule.

Chain rule. What if you have a function of a function (a composite function)? Here is an example.

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In this case, I can take the derivative of x as:

La te xi t 1

That one might be a little harder to explain – let’s just hope you cover that in your math course soon.

Why do we need derivatives in physics?

Remember that the derivative is really just a rate of change. We usually think of rate of change in physics as a derivative with respect to time. This leads to some of the familiar quantities:

La te xi t 1

But it’s not just time derivatives that we use. If you know the potential energy as a function of position, you can find the force that goes along with this potential with a space derivative.

La te xi t 1

If you knew the potential energy function for a spring, you could use that to find the force exerted by a spring (in the x-direction).


That’s not actually the best example since you normally determine the spring force as a function and use that to derive the spring potential energy function – but anyway, it’s still an example.

All of these examples are from the first semester of physics (mechanics and stuff). Hopefully by the time you are in the second semester of introductory physics you will have seen lots of derivatives in your math class. Trust me, there are many more cases where you have to use derivatives in the second semester of physics.

One final warning. Remember, this was just a “crash course” in derivatives. This should not be used as a substitute for an actual mathematics course in calculus.

Email Phishing Attacks Take Just Minutes to Hook Recipients

If you work in IT security, you’ve got one minute and 20 seconds to save your company from being hacked. This is not a drill. It’s the median time it takes for an employee to open a phishing email that lands on a company’s network and in their inbox, setting in motion a race to prevent data from leaking. That’s according to the new Verizon Breach Investigations Report, which is due to be released publicly tomorrow but was previewed to reporters today.

It’s no surprise that in the race to protect networks from hackers, the adversaries outnumber and outpower the defenders. But now we know just how rapidly the protectors have to act before their systems are lost to attackers.

“How long do you suppose you have until the first message in the campaign is clicked?” the authors of the report ask. “Not long at all, with the median time-to-first-click coming in at one minute, 22 seconds across all campaigns. With users taking the bait this quickly, the hard reality is that you don’t have time on your side when it comes to detecting and reacting to phishing events.”

Verizon noted that 23 percent of recipients open phishing messages. But simply opening an email won’t necessarily install malware on a machine. More dangerous are the 11 percent of recipients who go so far as to click on malicious attachments.

Verizon’s annual report, now in its eighth year, analyzes breach intelligence and data from multiple sources, including customers of Verizon’s forensics response division and customers of FireEye, the firm that investigated the recent hack of Sony Pictures Entertainment. It also examines data from cases investigated by law enforcement agencies, and from government and industry computer incident response teams around the world. This year, Verizon analyzed data involving nearly 80,000 breaches contributed by 70 different organizations.

The report each year rarely offers surprises but instead focuses on providing a broad view of trends and developments in criminal hacking and cyberespionage as well as trends and improvements in defensive efforts. The takeaway from the report is rarely encouraging, as hacking attacks increase in number and sophistication each year.

This year’s report shows, for example, that once inside a victim’s network, the siphoning of data occurs rapidly in some cases before companies can react. In 24 percent of breaches examined, for example, the intruders began siphoning data within minutes and seconds of gaining entry, giving defenders little time to detect the theft and respond. Though there is some indication that response times are improving. In 37 percent of the breaches examined, defenders were able to contain the attack within hours. And in an additional 30 percent of cases, they were able to contain the adversaries within days. The problem, however, lies in the fact that while organizations may be quick to respond when they discover an attack, it still takes them a long time to uncover a breach.

“Unfortunately, the proportion of breaches discovered within days still falls well below that of time to compromise,” Verizon notes in the report.

Typically, it takes months if not years to uncover a breach. In 2012, for example, FireEye reported that the average cyberespionage attack continued unabated for 458 days before the victim discovered the hack. Prior to this, it was normal to find attackers had been in a network two or three years before discovery.

White House CTO: Government Needs Tech Industry to Show Up

Megan Smith, the United States’ chief technology officer, says the U.S. government is still years behind countries like the United Kingdom in terms of embracing technology. And while she believes it’s possible to catch up, first, she says, the tech industry here needs to “show up” for its government.

“Government is only what we make of it,” Smith said on stage at the Building the Business of Civic Tech conference in New York City today. “If we show up, it’ll include our skills.”

We just have to show up so we can do the things we want to do. Megan Smith

This is advice that Smith herself has taken to heart, having left the private sector and a vibrant career at Google last year to become the country’s CTO last fall. Now, she’s calling on others to do the same.

But this will take some convincing. The standard Silicon Valley attitude to government has been that it gets in the way and slows things down, stymying the quick work that talented technologists could otherwise make of big, hairy problems. It’s the essence of Silicon Valley libertarianism: Why wait for the government to act, the thinking goes, when we can build nearly anything ourselves?

Think Differently

In her new role, Smith is urging the tech community to think differently; it’s a shift in mindset she says is already gradually beginning to take root. Smith is not the only high-ranking tech exec to take a government job recently. In February, LinkedIn’s former head of data products, DJ Patil, became the country’s chief data scientist. Last month, President Obama announced that former Twitter and Medium executive Jason Goldman would become the country’s first chief digital officer.

The more Silicon Valley talent the government recruits, Smith says, the more Silicon Valley practices the government is adopting. And that’s a good thing because the U.S. has a lot of catching up to do, Smith says, particularly compared to countries like the U.K., which she held up as a model of digital government.

Brits Doing It Better

Not only is the U.K. incorporating computer science into its national school curriculum, but it’s also embraced tech in the public sector by launching savvy tools such as an online marketplace where suppliers can list services for the public sector to buy. The goal of the platform is to speed up the process of government procurement, which sometimes stands in the way of the tech sector and the public sector working hand in hand. The U.K. also recently convened the D5, a G8-style summit of leading digital governments, including New Zealand, Estonia, South Korea, and Israel. Note which ally wasn’t invited.

But Smith says she believes the U.S. will soon join their ranks. Already, she says, she’s seeing hackathons pop up in unlikely places, including the Department of Interior. The Department of Health and Human Services, meanwhile, has held pitch competitions for new tech. Through a new digital government initiative called 18F, as well as the Presidential Innovation Fellows program, the government is also placing tech teams inside every government agency to promote innovation from within.

But there’s still a long way to go and a lot on the line. Though she doesn’t say it outright, at the core of Smith’s call for more tech leaders in government is the belief that simply improving the technology that runs the country can make a more immediate difference than sweeping policy changes that are likely to get stuck in congressional stalemates. One glaring example of this is immigration, which Smith called a “very bad user experience.” Making the visa application process simpler with technology is, in a sense, a way for the Obama administration to ease the immigration process without congressional approval.

“We just have to show up,” Smith says, “so we can do the things we want to do.”

Even If You Don’t Want a 4K TV, Vizio’s New 4K TVs Are Worth a Look

The new M-Series lineup brings Ultra HD resolution, a full-array backlight system, and up to 32 local-dimming areas to the masses. Several models in the series cost $1,000 or less. The new M-Series lineup brings Ultra HD resolution, a full-array backlight system, and up to 32 local-dimming areas to the masses. Several models in the series cost $1,000 or less. Vizio

At the moment, 4K TVs are a hard sell. The sets are pricey, content is scarce, and 4K streaming solutions are still a ways off. There’s not much incentive to become an early adopter.

Vizio is trying to change that, as its 2015 lineup includes Ultra HD models at prices modest enough to make taking the leap seem smart. They’re also packed with excellent contrast enhancement features, so they’re worth checking out even if you just plan to watch upscaled HD content.

The company’s new M-Series sets are its mid-range models—pricing starts at $600—but they come loaded with specs that would make them higher than high-end if we were looking at the market of one year ago. Some of the sets’ picture-quality enhancements are arguably more important than the 4K spec.

Vizio’s M-Series sets feature full-array LED backlighting systems, which generally give you a more uniform picture brightness. Compared to edge-lit sets—which are thinner, more common, and prone to light banding—a full-array panel usually costs more. But with a solid source of light comes a contrast riddle: In order to provide a balance of uniformity and sharp contrast between light and dark areas of a scene, a full-array set needs local-dimming technology. Not too long ago, a full-array TV with local-dimming tech cost a few thousand dollars. They were (and still are) the panel technology found at the upper reaches of major manufacturers’ LCD lineups. Since last year, Vizio has been offering the technology across its lower and mid-range lineups, at surprisingly low prices.

The Reference Series, which doesn't have a price or a release date just yet, is optimized for HDR video and Dolby Vision. It'll come with its own surround-sound system. The Reference Series, which doesn’t have a price or a release date just yet, is optimized for HDR video and Dolby Vision. It’ll come with its own surround-sound system. Vizio

The Ultra HD (3840×2160) M-Series TVs start out at $600 for a 43-inch set with 28 zones of local dimming. Granted, 43 inches is very small for a 4K TV—the smaller the set, the less you’ll notice a difference between 1080p and Ultra HD—but a $600 set with a full array backlight system, local dimming, and the ability to handle 4K sources is a hot bargain.

If you’re fine with a 120Hz refresh rate, the sweet spot in the M-Series lineup is probably the $1,000 55-incher, which ups the local-dimming tech to 32 zones. Starting at 60 inches ($1,500), the refresh rate for M-Series sets jumps up to 240Hz. The lineup tops out at $4,000 for an 80-incher with 32 zones. Regardless of size, all the new sets come with built-in Wi-Fi, Vizio’s VIA Plus app ecosystem, a keyboard-equipped remote, and five HDMI ports—one of which is an HDMI 2.0 port that supports HDCP 2.2.

Along with the new M-Series TVs, Vizio announced it would still be offering 1080p TVs, although the HD models are now limited to the even lower-priced E-Series ($180 for a 24-inch to $1,400 for a 70-inch, with different refresh rates, local-dimming zones, and inputs across the lineup). It also provided a bit more information about its upcoming Reference Series televisions, which it showed off at CES a couple years ago.

The Reference Series will have a modular base and stand. You can remove the bottom speakers and mount it on the wall. The Reference Series will have a modular base and stand. You can remove the bottom speakers and mount it on the wall. Vizio

The deal with the Reference Series, which will be the company’s new premium-level range, is that they’re built for high dynamic range (HDR) video. They’re 4K sets with very bright full-array backlights (800 nits) and 384 local-dimming zones. To your eyeballs, that translates to a wider color gamut, fireballs on TV looking almost as bright as fireballs in real life, and the ability to “see through” bright patches on screen and view detail due to the contrast performance.

In order to get the full effect, you’ll need to watch content mastered for Dolby Vision on the new sets. Vizio and Dolby announced that a few 4K Warner Bros. movies, including The Lego Movie, Man of Steel, and Into the Storm, will be available via Vudu in Dolby Vision.

The Reference Series TVs aren’t out yet, and Vizio says they’ll be released this year. That probably means they’ll be available in the fall, when the company usually announces its new higher-end P-Series TVs. They’ll certainly be expensive, and you should start clearing space in your living room now: These Reference Series models will be available in just two sizes: 65 inches and a crazy-huge 120 inches.

Justified Nears Its End, But It Leaves Behind Classic GIFs

After six seasons, Justified is finally readying its last stone-faced rejoinders. Graham Yost’s series wraps up tonight, and with the series finale looming, the now-badgeless renegade Raylan (Timothy Olyphant) and his small-town Kentucky nemesis Boyd Crowder (Walton Goggins) are both on the hunt for Ava Crowder (Joelle Carter) in the Appalachian hills—while Avery Markham (Sam Elliott), Loretta McCready (Kaitlyn Dever) and the inconceivably immortal Wynn Duffy (Jere Burns) all have parts to play.

From its indelible recurring villains to its bourbon-soaked charm, Justified has been a joy, though the road wasn’t without its bumps. After Elmore Leonard, the legendary crime writer whose short story “Fire in the Hole” inspired the show, passed away in 2013, and Yost and his staff knew the show’s end was in sight, the ensuing fifth season dipped in quality, and fans got nervous that the show wouldn’t wrap up in peak form. Thankfully, the final season has been lights-out all around: acid-soaked retorts, tense drama, and constantly shifting alliances have been the backdrop as the fate of Harlan County hangs in the balance. Though its best reaction GIFs are reserved for Olyphant’s killer smirk and stoic standoffs, Justified is still a cornucopia of memorable images. There are too many showdowns and one-liners for any mortal roundup, but we’ve compiled a killer selection to quick-draw from. We’ll miss you, Harlan County.

Remember Your ABC’s

The Use Case: Giving advice (especially on style blogs)

The Background: The silver-tongued Boyd Crowder is the scene-stealing Omega to Raylan’s Alpha. There are plenty of love and almost-love stories on Justified, but the most combustible pairing will always be these two—they came from the same coal-mining roots, only to wind up on opposite sides of the law, destined to face off again and again.

Geopolitics, Crothers Style

The Use Case: Specifically, regional arguments between Michiganders, but there’s plenty here to suit any and all arguments.

The Background: Every darkness needs its light, and Boyd more often than not has enough of the latter to make the former palatable.

The Patented Raylan Givens “Justified” Shooting

The Use Case: Keeping things on the up-and-up…but barely.

The Background: The entire impetus for the series was Givens’ “justified” quick-draw shooting of a mob hitman in Miami, leading to his reassignment to his home state of Kentucky. Bending the law to the point juuuust before it breaks is Raylan’s calling card.

Maybe You’re the Asshole

The Use Case: Somebody’s being a…you know.

The Background: Raylan Givens has a way with the expletives allowed on cable television. The above quote, from Season 6, is perhaps his best piece of inadvertent advice. (Of course, there are so many bits like that littered throughout the series that FX could sell a Raylanism-A-Day calendar.)

The Tao Of Tim

The Use Case: When your friend says something so inconceivably dumb that no words are as strong as a good eye roll.

The Background: Raylan doesn’t have a partner per se, but Tim Gutterson (Jacob Pitts) and Rachel Brooks (Erica Tazel) offer such dry counterbalance that they can make him look almost cuddly by comparison.

Here Comes the Judgment

The Use Case: Pulling out the big guns.

The Background: Ellstin Limehouse’s holler in Harlan County is one of the places that criminals and law enforcement alike fear to tread. His first appearance is not unlike Daniel Day-Lewis’ Bill the Butcher from Gangs Of New York, and immediately sets the tone for his character—a man not to be trifled with.

Keep It Sweet

The Use Case: Delivering the final blow.

The Background: Raylan’s father Arlo Givens (Raymond J. Barry) is a thorn in the Marshal’s side throughout the first four seasons, as a petty criminal always showing up in the wrong places. Even after his death, he haunts Raylan’s mind; Raylan’s hallucination of Arlo in one episode during Season 6 was the perfect curtain call for a perfect role.

The Un-Killable Wynn Duffy

The Use Case: Basically any comments section in the history of the Internet.

The Background: Of all the characters to meet sticky ends during Justified’s run, Wynn Duffy seemed the most likely to get offed at almost every juncture. And yet, slick cockroach that he is, he survived through to the series finale, as nearly every associate he’s ever been around on the show dies in increasingly ridiculous fashion.

That Classic Raylan Givens Smile

The Use Case: When you want to turn on the smolder.

The Background: Timothy Olyphant was fantastic as Seth Bullock on David Milch’s classic HBO series Deadwood, but his defining role now and forever will be Raylan Givens. That cowboy smirk peering out from under the weathered brim of a cowboy hat never gets old.

Ev Williams’ Rules for Quality Content in the Clickbait Age

Ev Williams. Ev Williams. Andrew White/WIRED

When Medium launched in 2012, the BuzzFeed-ification of content and content business models hadn’t quite hit. Twitter co-founders Evan Williams and Biz Stone wanted to build a beautiful, easy-to-use platform for very good writing on the web, but the idea seemed naïvely optimistic; wouldn’t writers choose to publish their work where the audience was largest and the paycheck most lucrative?

Nearly three years later, the state of the digital media business is in chaos. Social distribution in the form of Facebook and Twitter has all but replaced search and homepages as the most critical means of content discovery and distribution. Publishers and advertisers have leaped across the firewalls that once kept them separate, joining forces to create new types of content and marketing. Programmatic advertising, which relies on software to aggregate and sell audiences across sites rather than selling ad space on a specific publication, is on the rise.

This idea that anyone shows up to any conversation and injects whatever they want is a bad idea. We chose to prioritize audiences feeling safe. Ev Williams

Yet over the same period of time, Medium has grown to a robust 25 million unique visitors (self-reported) each month. (For comparison, that’s roughly the same as the British newspaper The Guardian.) Although it has tried a few experiments with advertisers, Medium has not yet turned its attention to how to make money. Its assumption is that once the content exists, opportunities will follow.

Instead, Williams, who is CEO, has focused on making the best tools possible for writers and readers. Consider Medium a case study for quality in the digital age; Williams has been able to achieve this growth entirely by giving both writers and readers more of the tools and the products they want, without yet sullying these efforts with money-making endeavors.

Last week, Williams and I met at Medium’s New York office for a wide-ranging conversation in which he shared some of his biggest lessons to date on trying to create a venue for quality and civility in an age of clickbait. A few of his most important takeaways:

1. Metrics don’t tell you what you need to know most

The number of people visiting Medium and the amount of time they spending on the site are growing. Comscore reports the company has seen an 80 percent spike in visitors in the past year. Williams prefers to call out the total time Medium visitors spend reading, a metric he calls “TTR.” Since 2012, visitors have spent 1.5 million hours reading on Medium. Williams says unique visitors, the standard metric cited by online publishers to gauge the size and value of their audiences, is “a highly volatile and meaningless number for what we’re trying to do.”

The goal, according to Williams, is not to get the maximum audience for a piece of writing, but the perfect audience. Whether you want to publish a post announcing a job change to several hundred business contacts, as I did last August, or you want to publish a feature on Snapchat’s security team to a mainstream audience of tech enthusiasts, as tech journalist Steven Levy did recently on Backstory, Williams wants to guarantee you find exactly the people you’re looking for. “Eventually we want to get to, ‘If you publish on Medium, you’ll get maximum efficient audience,’” he says. The existing metrics don’t do much to show progress toward that goal.

2. It’s harder than you think to help people talk to each other …

Like most websites in 2015, Medium becomes more interesting when users link it to their social feeds. Williams calls this “the people layer,” and he’s trying to design the social experience on Medium to allow authors and readers to engage each other in meaningful ways around the posts. Some of these actions, like the “recommend” button or the “response” section after a post, mirror other publishers. But Medium allows readers to make comments to the author directly in the text as they read. The comments show up in the margin, and authors can choose whether to make them visible to the broader audience. This offers the author protection Williams find important, encouraging her to be more vulnerable.

A few weeks ago, Medium added the ability to highlight portions of text, one of Williams’ favorite features to date. “I compare it to the difference between giving a very abstract compliment versus a specific compliment,” says Williams. “To see what people are highlighting is valuable and makes you feel good as a sharer.”

3. … but it’s easier than you think to help people be civil to each other

People get attacked on Medium, just as they do all over the web. But it happens “much much less,” says Williams, “both for audience and architectural reasons.” Early on, Medium introduced comments that appear in line. “Because authors have to flip the switch to show them, there’s less motivation [to flame writers] because you can’t do it publicly,” says Williams. Medium also has a response feature that allows readers to leave comments at the bottom of the post; comments aren’t made public unless the original poster approves it.

4. The key to civil conversation online is getting your social tools right

Williams compares conversing on the Internet to conversing in real life. “I like having dinner parties, but I don’t leave my front door open when I have dinner parties and say to whoever walks by [come in],” he says. “That’d be great, but that’s not the world we live in and the Internet, if it ever was that, is not that today.”

Williams is investing in building the right controls to make sure Medium’s social features amplify useful conversations while downplaying haters. “This idea that anyone shows up to any conversation and injects whatever they want is a bad idea,” says Williams. “We chose to prioritize audiences feeling safe. That’s why we structure notes the way we do, even though there’s a little bit of friction.”

The friction Williams identifies is the lag time involved in waiting for an author to review a comment and decide whether it can be posted publicly. If Medium were optimizing purely for traffic or engagement, the publisher would want comments to appear in realtime in order to keep the readers engaged with the post longer. Says Williams, “The point—that you can’t get attacked—is something we’ve thought about from the beginning. We’ve tried to create a place where you can speak your mind and feel safe, and at the same time create a place for intelligent public debate.” Users can turn comments off entirely, and starting soon, they’ll be able to block readers who are abusive.

5. One word: platishers

“Platishing” is the term Williams uses to describe the hybrid business Medium has become. It’s a software platform on which writers can easily publish just about anything. But it also produces five publications on that platform, including the general interest Matter (“A magazine for a generation who grew up not caring about magazines”), the music `zine Cuepoint , and the tech pub Backchannel . “There’s no controversy internally or struggle existentially about what we are. My expectation was always that people will get over this dichotomy,” he says. “That’s what digital things do in general. They blur lines.” As examples, he mentions Snapchat and Apple (“A platform, or a publisher?”).

The point of the publications is to experiment with how professional publishers can use Medium. “We want Medium to be the default platform not just for individuals and organizations who aren’t in the publishing business,” he says. “We want it to be a great alternative for those who are professionals, whether it’s the next Nate Silver or someone from the traditional world saying ‘I want to start my own thing.’” In fact, a spate of editorial types are doing just that. The most developed is Midcentury/Modern , a collection of stories for baby boomers created by author Debbie Galant, that has its own URL published on the Medium platform.

6. People write more when they start out publishing to smaller audiences

Writers want to be read. Williams says they’re starved for audience. “Attention is this valuable and scarce commodity,” he says. “But the fear of an audience can have a chilling effect.” He thinks a lot about how to help writers feel safe enough to express themselves, first by writing for smaller audiences, and then by reposting their thoughts to a broader audience once they’ve gotten some feedback.

Williams is experimenting with this at Medium. The company has always kept an internal blog on which all 90 employees can post project updates, thoughts, and suggestions. Last fall, Williams suggested republishing some of these musings as public posts on Medium. “While reading it, I realized a lot of this stuff is super-funny and smart and would help those who care understand what we are doing,” he says. They’re now included in a collection called “Inside Medium.”

There may even be a future business opportunity for Medium in creating enterprise products that allow companies to broadcast internal posts to a broader audience. “It would make a lot more companies more transparent and authentic,” he says.

7. The written word is the most powerful form of media

Unlike nearly every other big web publisher in 2015, Williams doesn’t have big plans for video. “Medium should be the best platform for sharing stories and ideas and those could come in any form, but we haven’t invented anything new or valuable to do in video.”

Partly, that’s because Williams is a purist about writing. “Video is incredibly powerful and influential, but not for the average person. The still image has it for accessibility but not for influence. It’s the very, very, very rare photo that actually conveys idea or meaning,” he explains. “The written word is the most accessible yet powerful form of media there is.”

Angry Nerd: Unfriended’sScreen-Capture Format Is Lazy, Not Scary

Angry Nerd: Unfriended’sScreen-Capture Format Is Lazy, Not Scary

Docker Raises $95M Because Silicon Valley Loves Containers

Silicon Valley loves containers. Not the big metal boxes that carry cargo on ships, but containers made out of code. These virtual containers make it easy to move and run software across the thousands of computers that make up today’s massive data centers.

Open source cloud computing startup Docker has done more than any other company to popularize containers. Now the San Francisco-based upstart has raised $95 million to help it fend off the competition. The venture capital round announced by the company today is its fourth, and its second round since changing its name from dotCloud to Docker in 2013. That’s a lot of money, but Docker may well need it as the startup competes an increasingly crowded market—a market it helped to create.

The company’s main product, also called Docker, enables developers to bundle applications into “containers” that can be easily moved around and run anywhere. For example, it can be used to run an application developed on a programmer’s laptop on a cluster of servers running in a data center, or to move that application from one data center to another. You can think of Docker containers as a more efficient alternative to virtual machines.

That relatively simple idea turned Docker, originally a cloud hosting provider, into an overnight sensation. While containers are an older idea and have been part of Linux and similar open source operating systems for years, Docker’s success lies in its developer-centric approach to creating these useful tools. Since the company open sourced its tools, Docker radically altered the cloud computing landscape. Practically every cloud computing and web infrastructure company on the planet, from Amazon to Oracle to Red Hat, is integrating their products with Docker, and you can’t attend a developer conference these days without hearing at least a couple talks on containers.

Meanwhile, Docker has spawned many complementary tools such as Google’s container management system Kubernetes and Docker-based cloud platforms such as Flynn and Deis. But it’s also spawned some competitors.

Last year a company called CoreOS, which makes a custom version of the Linux operating system designed specifically for containers, announced its own Docker alternative called Rocket. Earlier this month CoreOS raised $12 million from Google Ventures and other investors, promising tighter integration with Kubernetes. Microsoft, meanwhile, has launched its own answer to containerized operating systems called Windows Server Nano. And don’t expect old school virtualization companies like Citrix and VMware to go quietly into the night.

In short, container mania is just getting started, and it’s not clear that Docker will be able to continue to dominate the category it practically created. But this latest round of funding means the company won’t go down without a fight.

McLaren Helps Build a $20,000 Bike, Because Why Not

As I lean into the turn, a slight mist from the Pacific Ocean beads up on the chrome-accented top tube. The sun burns through the haze hanging over the sleepy, deserted coastal road just outside Santa Cruz, while this $20,000 Specialized S-Works McLaren Tarmac bicycle and I get to know each other. The process repeats over and over: lean into a turn, tap the brakes to burn off speed, jump on the pedals, and accelerate coming out of a corner.

Hugging the fog line, I roll up and down every inch of road I can find within a few square miles. Through the taut frame, I swear I feel every rock and the viscosity of the tar that binds them together. As cars pass me, it’s funny to think how many of them cost less than my ride.

I’ve ridden plenty of bikes from Specialized. I know the feel of the standard Tarmac, its refined carbon road racer, which costs between two and ten grand. But this bike is something quite different, as befits anything with this kind of price tag and limited production run (just 250 were made).

mclaren-bike-2 McLaren

The McLaren Tarmac is the latest result of a years-long partnership between Specialized and McLaren, the world renowned maker of F1 race cars and supercars for the wealthy. The pedigree is obvious, its refinement immediately noticeable by racing aficionados.

But with a price tag that most people (myself included) would consider astronomical or even ridiculous, this bike has to not only feel different, but be different, especially since it’s not alone in the rarified category of $10,000 and up bikes. Choices include Felt’s FRD series, the Cervelo Rca, Pinarello Dogma, plus one-offs from builders like Davidson, Sachs, and Vanilla.

So what does McLaren, master of four wheels, bring to the bicycle game, apart from some sweet orange paint and a fancy name?

It’s data, says Sam Pickman, Specialized’s lead engineer. It’s the intent and the experience: what a bike is designed to do, how it handles, and the way it connects to the ground for a distinctive Tarmac feel. With McLaren’s help, the Tarmac’s ride quality was computer modeled and fed by stiffness, weight, and geometry. Pickman won’t couch up the exact numbers—trade secret and all—but everything the company does relies on data. The main lesson learned from its relationship with McLaren is to prove their decision and trust the numbers.

mclaren-bike-3 McLaren

That makes for a new kind of development process. With McLaren consulting, Specialized gained a new understanding of the complex “bike-rider system,” a specific number to codify what you experience in the saddle when going all out on race day or at a relaxed pace around town. That “code” is the stiffness and damping of all the components in various directions that add up to the desired ride. It considers everything, from the rubber to what’s in between the wheels.

So confidant in its McLaren-infused process, Specialized is diving right into production. In the past, it took a bunch of revisions in the production process for any one bike to get things exactly right. For this model, it’s made just one or two. That’s not a one time change for the limited run of the $20,000 Tarmac: Specialized says the approach will trickle down to its more affordable bikes.

Unfortunately for the few people with $20,000 to burn on a bike, the model I took down the coast was part of a limited, sold out, run. The good news is that the vehicle dynamics know-how from McLaren gave Specialized a template for their next generation of bikes, so the next (reasonably priced) Tarmac you ride should have a lot more data behind it.