Sony’s 13” Digital Paper business notepad: Not dead yet, apparently—and here’s how you can buy one

SonyDigitalPaperpSNYNA-DPTS1_alternate4_v500Good E-Reader has a piece announcing the imminent demise of the Sony Digital Paper notepad. The problem is, Sony’s current online store for the U.S. knows of no such plans. We talked to the store. The real news is that the e-commerce site is shutting down August 28—not the discontinuation of the reader.

Sony’s future online operations instead will send people to  authorized retailers, a complete list of which is here. Alas, the list isn’t geographically organized. But you’ll presumably see some familiar names and can find out if Sony Digital Paper notepad will be available. What’s more you might be able to order the reader online through eBay outlets.

The fact that the reader was even for sale was news to me, as I hadn’t been aware that Sony had been selling it. We last mentioned it in 2013 when Sony was developing it, but they actually started selling it in May of 2014—and sold out of their distribution channels so fast they had to start selling it directly in August.

It seems to be a specialty device—a $799 13.3” e-ink notepad (originally $1,100 when they started selling it last year), with an attached stylus pen for writing on documents, that seems to see most of its use by businesses. That makes sense; they’d be most interested in being able to see documents displayed at their original size and make notes on them, and would be able to afford to drop a grand on a device that could do it. Certainly it has never been never connected to Sony’s consumer-facing e-book store that  closed down in February, 2014.

The slate is a boutique gadget and sold without customer service support. Apparently Sony’s telephone hotline to order it is quizzing potential buyers on their level of technical expertise and is refusing to sell it to them if they don’t know enough.

(Revised to reflect an update in The Digital Reader.)

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How to Install and Configure MongoDB on Ubuntu 14.04

MongoDB is a NoSQL database that offers a high performance, high availability, and automatic scaling enterprise database. Data is stored in a “document” structure in JSON format (in MongoDB called BSON). MongoDB was first introduced in 2009 and is currently developed by the company MongoDB Inc. This tutorials shows the installation and configuration of MongoDB on Ubuntu 14.04.

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Exploring abandoned Second Life virtual college campuses

screen-shot-2015-08-12-at-1-59-42-pmOne of the clever bits of invention in Ernest Cline’s Ready Player One is the establishment of schools in the virtual reality game world where everybody games. But it turns out this wasn’t entirely an invention, as back in 2007, many colleges established virtual campuses in the Second Life virtual-reality game—and some of them are still around, albeit abandoned. On, Patrick Hogan writes about taking a tour of some of these campuses.

And “abandoned” is the word. Hogan writes:

First, I didn’t see a a single other user during my tour. They are all truly abandoned.

Second, the college islands are bizarre. They mostly are laid out in a way to evoke stereotypes of how college campuses should look, but mixed in is a streak of absurd choices, like classrooms in tree houses and pirate ships. These decisions might have seemed whimsical at the time, but with the dated graphics, they just look weird.

The article is full of interesting screenshots with dated graphics. Judging from the campuses on display, it looks like educators of the day saw the virtual space’s potential but weren’t really sure what to do with it—so what they did do didn’t have any staying power. Hogan did find the campuses’ overall weirdness delightful by comparison to the bland reality of most Internet schools these days. He also wondered who was paying for their upkeep, given that it costs hundreds of dollars per month to maintain a virtual space in Second Life.

I suppose one of the things that’s really missing for virtual schools to be effective is a truly good implementation of virtual reality. The VR schools in Ready Player One are possible largely because they have a form of VR that’s effectively as good as real life. Out here in the real world, we have monitors and keyboards—and there’s no point in trying to make believe you’re in a virtual college campus if the cheesy graphics are just going to be a distraction from the education.

We’ll just have to keep working on that.

The post Exploring abandoned Second Life virtual college campuses appeared first on TeleRead.

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Show HN: Algebra.js – Build, display, and solve algebraic equations

var expr = new Expression("x");
expr = expr.subtract(3);
expr = expr.add("x");

var eq = new Equation(expr, 4);

var x = eq.solveFor("x");

console.log("x = " + x.toString());

Right Now

Chrome / OS X: Cmd + Option + J

Chrome / Windows: Ctrl + Shift + J

Firefox / OS X: Cmd + Option + K

Firefox / Windows: Ctrl + Shift + K

In the Browser

Download algebra.min.js.

<script src="algebra.min.js">

In Node

var algebra = require('algebra.js');

The main objects available are Fraction, Expression, and Equation.

var Fraction = algebra.Fraction;
var Expression = algebra.Expression;
var Equation = algebra.Equation;


Add, subtract, multiply, and divide fractions by either integers or other fractions. Fractions are automatically

var frac = new Fraction(1, 2);

frac = frac.add(new Fraction(3, 4));

frac = frac.subtract(2);

frac = frac.multiply(new Fraction(4, 3));

frac = frac.divide(5);


Initialize expressions with a variable name.

var x = new Expression("x");

Add / Subtract

Add or subtract integers, fractions, variables, or other expressions to or from expressions.

var x = new Expression("x");

x = x.add(3);

x = x.subtract(new Fraction(1, 3));

x = x.add("y");

var otherExp = new Expression("x").add(6);

x = x.add(otherExp);
x + 3
x + 8/3
x + y + 8/3
2x + y + 26/3

When adding / subtracting an expression to / from another expression, any like-terms will be combined.
Keep in mind the distributive property when subtracting expressions.

var expr1 = new Expression("a").add("b").add("c");
var expr2 = new Expression("c").subtract("b");

var expr3 = expr1.subtract(expr2);

console.log(expr1.toString() + " - (" + expr2.toString() + ") = " + expr3.toString());
a + b + c - (c - b) = a + 2b


Multiply expressions by integers, fractions, variables, or other expressions.

var expr1 = new Expression("x");
expr1 = expr1.add(2);
expr1 = expr1.multiply(4);

var expr2 = new Expression("x");
expr2 = expr2.multiply("y");
expr2 = expr2.multiply(new Fraction(1, 3));
expr2 = expr2.add(4);

var expr3 = expr1.multiply(expr2);

console.log("(" + expr1.toString() + ")(" + expr2.toString() + ") = " + expr3.toString());
(4x + 8)(1/3xy + 4) = 4/3x^2y + 8/3xy + 16x + 32


Divide expressions by either integers or fractions.

var x = new Expression("x").divide(2).divide(new Fraction(1, 5));


Raise expressions to integer powers.

var exp = new Expression("x").add(2);

var exp3 = exp.pow(3);

console.log("(" + exp.toString() + ")^3 = " + exp3.toString());
(x + 2)^3 = x^3 + 6x^2 + 12x + 8


Evaluate expressions by substituting in fractions, integers, or other expressions for variables. Evaluating an expression for only some of its variables returns an expression object. Evaluating an expression for all of its variables returns a fraction object.

Integers and Fractions

var expr = new Expression("x");
expr = expr.multiply(2);
expr = expr.multiply("x");
expr = expr.add("y");
expr = expr.add(new Fraction(1, 3));


var answer1 = expr.eval({x: 2});
var answer2 = expr.eval({x: 2, y: new Fraction(3, 4)});

2x^2 + y + 1/3
y + 25/3

Other Expressions

var expr = new Expression("x").add(2);


var sub = new Expression("y").add(4);
var answer = expr.eval({x: sub});



Build an Equation

Build an equation by setting an expression equal to another expression or to an integer or fraction.

var z = new Expression("z");

var eq1 = new Equation(z.subtract(4).divide(9), z.add(6));

var eq2 = new Equation(z.add(4).multiply(9), 6);

var eq3 = new Equation(z.divide(2).multiply(7), new Fraction(1, 4));
1/9z - 4/9 = z + 6
9z + 36 = 6
7/2z = 1/4

Solve Linear Equations

One Variable

If a linear equation only has one variable, solving for that variable will return a fraction object.

var x1 = new Expression("x");
x1 = x1.add(new Fraction(2, 3));
x1 = x1.divide(5);

var x2 = new Expression("x");
x2 = x2.divide(7);
x2 = x2.add(4);

var eq = new Equation(x1, x2);

var answer = eq.solveFor("x");

console.log("x = " + answer.toString());
1/5x + 2/15 = 1/7x + 4
x = 203/3

Multiple Variables

If a linear equation has more than one variable, solving for a variable will return an expression.

var expr1 = new Expression("x");
expr1 = expr1.add(5);
expr1 = expr1.divide(4);

var expr2 = new Expression("y");
expr2 = expr2.subtract(new Fraction(4, 5));
expr2 = expr2.multiply(3);

var eq = new Equation(expr1, expr2);


var xAnswer = eq.solveFor("x");
var yAnswer = eq.solveFor("y");

console.log("x = " + xAnswer.toString());
console.log("y = " + yAnswer.toString());
1/4x + 5/4 = 3y - 12/5
x = 12y - 73/5
y = 1/12x + 73/60

Solve Quadratic Equations

An equation is quadratic if it can be arranged into the form

$$ax^2 + bx + c = 0$$

where $a neq 0$.

A quadratic equation has at least one real root if its discriminant, $b^2 – 4ac$, is greater than or equal to 0.
Solving a quadratic equation with a discriminant that is greater than or equal to 0 returns an array of its real roots as either Fraction objects or numbers,
depending on if the roots are rational or irrational, respectively. Solving a quadratic equation with a discriminant that is less than 0 will return an empty array.

var n1 = new Expression("x").add(5);
var n2 = new Expression("x").subtract(new Fraction(3, 4));

var quad = new Equation(n1.multiply(n2), 0);


var answers = quad.solveFor("x");

console.log("x = " + answers.toString());
x^2 + 17/4x - 15/4 = 0
x = -5,3/4

Solve Cubic Equations

An equation is cubic if it can be arranged into the form

$$ax^3 + bx^2 + cx + d = 0$$

where $a neq 0$.

All cubic equations have at least one real root. Solving a cubic equation returns an array of its real roots as either Fraction objects or numbers.

var n1 = new Expression("x").add(2);
var n2 = new Expression("x").add(3);
var n3 = new Expression("x").add(4);

var cubic = new Equation(n1.multiply(n2).multiply(n3), 0);


var answers = cubic.solveFor("x");

console.log("x = " + answers.toString());
x^3 + 9x^2 + 26x + 24 = 0
x = -4,-3,-2

Solve Quartic Equations

Coming soon.

Solve Anything Else

Equations will only be solved if there is an algebraic solution or if the variable being solved for can be isolated through arithmetic operations. Attempting to solve an equation that does not fit these criteria returns undefined.

var expr = new Expression("x");
expr = expr.multiply("x");
expr = expr.add("x");
expr = expr.add("y");

var eq = new Equation(expr, 3);


var xAnswer = eq.solveFor("x");
var yAnswer = eq.solveFor("y");

console.log("x = " + xAnswer);
console.log("y = " + yAnswer.toString());
x^2 + x + y = 3
x = undefined
y = -x^2 - x + 3

Make things pretty with LaTeX. All classes have a .toTex() method for rendering LaTeX. Combining this with
KaTeX, for example, is easy.


<div id="myEquation">
<div id="mySolution">
var a = new Expression("x").pow(2); var b = new Expression("x").multiply(new Fraction(5, 4)); var c = new Fraction(-21, 4); var expr = a.add(b).add(c); var quad = new Equation(expr, 0); katex.render(quad.toTex(), myEquation); var answers = quad.solveFor("x"); katex.render("x = " + answers.toTex(), mySolution);

Greek Letters

Also supports Greek letters, obviously!

<div id="expr1">
<div id="expr2">
var lambda = new Expression("lambda").add(3).divide(4); var Phi = new Expression("Phi").subtract(new Fraction(1, 5)).add(lambda); katex.render(lambda.toTex(), expr1); katex.render(Phi.toTex(), expr2);

Check out the list of Greek letters available.

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RetroPie 3.0 Adds Automatic Controller Configuration, Wi-Fi Setup, and More

RetroPie is our favorite image for turning your Raspberry Pi into a retro video game station , and today it gets a bunch of great features.…

Read more…

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Windows 10 drives users to MediaPortal alternative


The release of Windows 10 spelled the end for Media Center. It wasn’t unexpected, users have known it was coming for a while, as Microsoft had ceased developing the service. That didn’t make the loss any easier for the loyal following of HTPC users.

From Microsoft’s abandonment, other businesses grow. MediaPortal, which has been a solid solution for quite some time now is one. Though, other options for Media Center refugees also exist.

MediaPortal announces an influx of new downloads since Microsoft’s latest operating system release. “The Team MediaPortal notices an increase of downloads of both MediaPortal 1 and MediaPortal 2 at the time when Windows 10 update started to be delivered. Besides the raw numbers, there is also a trend regarding download origins: now the United States are on top with 30 percent”, the organization announces.

MediaPortal 1 and 2 are separate versions that bring different things to the user. You’ll need to decide which you’d prefer to go with. The website will describe each. Both are free, though.

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Removing the 140-character limit from Direct Messages

If you’ve checked your Direct Messages today, you may have noticed that something’s missing: the limitation of 140 characters. You can now chat on (and on) in a single Direct Message, and likely still have some characters left over.

While Twitter is largely a public experience, Direct Messages let you have private conversations about the memes, news, movements, and events that unfold on Twitter. Each of the hundreds of millions of Tweets sent across Twitter every day is an opportunity for you to spark a conversation about what’s happening in your world. That’s why we’ve made a number of changes to Direct Messages over the last few months. Today’s change is another big step towards making the private side of Twitter even more powerful and fun.

You may be wondering what this means for the public side of Twitter. In a word, nothing. Tweets will continue to be the 140 characters they are today, rich with commentary as well as photos, videos, links, Vines, gifs, and emoji. So, start working on those sonnets.

We’ll begin rolling out this change today across our Android and iOS apps, on, TweetDeck, and Twitter for Mac. It will continue to roll out worldwide over the next few weeks. If you can’t wait to try out longer Direct Messages, be sure you’re using the latest versions of our apps so you get the update right away. Sending and receiving Direct Messages via SMS will still be limited.

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