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3 years ago

What is recovery? [Android A to Z]

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What is recovery?  In Android, recovery refers to the dedicated, bootable partition that has the recovery console installed.  A combination of key presses (or instructions from a command line) will boot your phone to recovery, where you can find tools to help repair (recover) your installation as well as install official OS updates.  Because Android is open and has the recovery source code available, building a customized version with more and different options is relatively easy as well.  Let's look at both options.

The stock recovery is pretty limited, but that's by design.  Its main purpose is to delete all user data and files, or to perform system updates.  Normally, both these operations are started from the running Android system, or you can do things manually and boot right into recovery yourself.  When you tell your phone to do a factory reset, recovery is what boots up and erases the files and data.  Likewise with updates -- when we restart to install an official OS update, it's done in recovery.  Recovery is also where we go to manually install official OS updates we've downloaded from the Internet.  It's very useful, but limited.

Custom Android recoveries offer much more.  They have been coded to allow for backup and restore functions, selective deletion of data so you don't have to wipe everything, and modified to allow update packages that have not been digitally signed by official sources.  You also can mount various partitions so that you can copy files to the SD card without having to remove it or reboot into Android. Anytime you see someone mentioning Clockwork or Amon Ra, they're talking about custom recoveries.  Because of the extra functionality built in, they are a pretty important tool for folks who want to hack their Android phone or tablet.  Recoveries aren't as pretty as a custom ROM and don't get the same love from users and bloggers that custom builds of Android do, but in the end they're even more important. Without them none of this custom ROM stuff would be possible.  

Previously on Android A to Z: What is a QR Code?; Find more in the Android Dictionary

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3 years ago

Galaxy Nexus tips and tricks [From the forums]

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So you got a shiny new Samsung Galaxy Nexus in your hands and you are left wondering exactly just what it can do, and how to do it. It's the first device to launch with the newest Android operating platform, Ice Cream Sandwich, and while the core functionality is the same as older versions, a lot has changed, too. From the on-screen buttons to the new menu locations, there's a good chance you're stumbling around a bit while using your new phone.

We have the best forum community in the Android world, and great folks just like you and I are always working hard to bring nothing shy of the best for everyone. Forums member milominderbinder has taken some time to create an extremely comprehensive guide of tips and tricks to make your experience with your new Galaxy Nexus even better. From things as simple as the new navigation methods to fixes for Facebook sync and much more, this guide is a must read. A few tidbits:

  • How to get Facebook Sync working
  • Change the notification LED
  • No microSD card? No problem
  • Low speaker volume
  • Camera focus
  • Messaging fixes

The list goes on and on. And that's one of the great things about having a Nexus device. While it's better than many straight out of the box, you also can apply more tweaks than you have time for in any given day and make the phone just as good as it can be. And because it's a Nexus device, you also can start from scratch anytime you want, or back up your phone with a custom recovery. Whether you think you have a pretty good feel of the device or you just grabbed one, you can definitely learn something from milo's guide.

Discuss in the Android Central Forums

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3 years ago

Android A to Z: What is a QR code?

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What is a QR code? These things are everywhere nowadays. Little square barcode-looking things. They're on website, they're on pictures, they're on advertisements -- they're everywhere. So what's a QR code and what do you do with it?

In a nutshell, a Quick Response Code is used to tell your phone to do something. Invented by Toyota in the mid-1990s, they "store" more information than traditional UPC barcodes and work better with languages more complicated than English. (Which is to say, most of them, especially in Asia.)

The way it works is this: Using a scanning app (there's Google's own Goggles app, or plenty of others in the Android Market), your phone's camera scans the code and then interprets it. There are different versions of QR codes, which can contain different amounts of information. 

Most often, QR codes are used to link to a website or video or some other online content. Your scanning app should preview the link for you as a safety feature so that you can't be automatically redirected to a malicious (or otherwise untoward) website or video.

Here at Android Central, you'll regularly find QR codes to quickly link to applications in the Android Market.

Previously on Android A to Z: What is a PRL?; Find more in the Android Dictionary

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3 years ago

What is a PRL? [Android A to Z]

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What is a PRL?  PRL stands for Preferred Roaming List and is a database used in CDMA (think Sprint and Verizon here) phones.  It's built and provided by your carrier, and used when your phone is connecting to the tower.  It indicates which radio bands, sub-bands, and service provider IDs will be searched for, then allows the phone to connect to the correct tower.  Without a correct and valid PRL, your phone won't be able to roam outside your home network, and may not be able to connect at all inside the network.  The database consists of an Acquisition table, which lists which radio frequencies to search for in which areas, and a System table, which tells the phone which towers it is allowed to connect to, and the preferred order.

Notice we said it connects to the correct tower and not the strongest tower.  If you're in an area with weak but steady signal from your carrier, the PRL will connect you to that signal rather than connect to a stronger signal on a different carrier.  When Palm released the Pre on Sprint (the first CDMA smartphone with "root" access to the system) people quickly learned how to hack the PRL to force a connection on Verizon towers in areas of poor Sprint coverage.  The same thing is done today with certain CDMA Android phones, and usually ends up with the same result -- a letter from your carrier telling you it's been nice having you as a customer, but it's time to part ways.  Not all hacking is good, kids, and when it adversely affects the network, it makes the other, good kind of hacking look bad.   

The PRL is usually sent as an over-the-air update when needed, but often -- especially if you travel a lot -- it's necessary to manually update it.  It's pretty easy to do:

  • Sprint: dial ##873283#
  • Telus: dial *22803 
  • Metro PCS, US Cellular, Verizon (3G phones only): dial *228

Android phones also have an option to update the PRL in most CDMA phones, you'll find that in the settings pages.  If you have a CDMA/LTE phone on Verizon or Metro PCS, your PRL will auto-update as needed, so don't fool with it.  Also it's not a good idea to update your PRL while you're roaming on another carrier.  

Previously on Android A to Z: What is open-source?; Find more in the Android Dictionary

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3 years ago

What is open source? [Android A to Z]

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What is open source? Open-source software is software that makes the source code freely available, for anyone to see and use. There are different open-source licenses that have different use conditions, from the GPL (GNU General Public License) -- which allows "free distribution under the condition that further developments and applications are put under the same license" -- to more liberal licenses like the Apache License, which doesn't require modifications to be open and have the source code available.  Android uses both of these licenses, and we'll have a look at them in turn.

The Linux kernel that is used in the OS is covered under the GPL.  This means that any changes made to the source code must be made available when a binary (geek-speak for a compiled, executable piece of software) is released to the public.  This means manufacturers like HTC, Samsung, Motorola and the rest must release the kernel source-code for any devices they sell at the same time they begin selling them.  For the most part, hardware manufacturers are pretty good about doing so, but they often miss the time frame and release the source code a little later than we would like.  These are the code releases you see us mention -- the kernel and other open-source "bits" that are covered under the GPL.

The Android OS source code is released mostly under the Apache License.  Anybody is allowed to download the source code and change it however they like, but they are not required to make their changes available in source code form to the public.  This is why we can't change and recompile things like HTC Sense or MotoBlur -- the changes to the base Android source code aren't available to us.  While many folks (myself included) don't like this situation very much, it does make sense from a business standpoint.  If manufacturers had to share all of their secrets, there wouldn't be as much monetary incentive to innovate, so the source was offered with a far more liberal license.  It certainly worked, as we see devices from many major players in the electronics world.

Previously on Android A to Z: What is NFC?; Find more in the Android Dictionary

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3 years ago

What is NFC? [Android A to Z]

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What is NFC?  NFC stands for Near-Field Communication and is a set of standards (established in 2004) for small, portable devices to establish radio communications with each other. Devices need to be close, usually no more than a few centimeters apart (and often they need to touch), which is why it's a Near-Field way to communicate. The standards cover data exchange formats defined by the NFC Forum (no, not that kind of forum) and are based on the original radio frequency identification (RFID) standards.  The forum also certifies devices like tags, cards, and smartphones.  

The coolest part of all this is that only one of the devices needs to be "smart."  Most of us has a credit card of some sort that we can tap against a payment machine, either at the gas pump or a cash register.  Both the payment machine and the credit card are NFC devices, but the card only has a string of information electronically written to a tiny chip embedded inside it.  And this is useful for other things, like starting and handling more robust communications like Wifi or Bluetooth, but most often it's used with one of these "dumb" chips.  These dumb chips can be written with any information, and the smart device determines what happens when communication is established.  

Of course, what most of us here think of when we hear NFC is Google Wallet.  Google Wallet takes things a step further by using your Android phone as both a smart device and a dumb device.  When you tap your phone at McDonald's to pay for those McNuggets, it's simply sharing your credit card credentials like any card would.  But there's functionality and hardware there to accept payments, track balances, provide security and more.  Right now it's only officially available as a test on the Nexus S 4G, but it's been hacked onto other phones with NFC hardware.  Soon, we'll see it (and other apps for things like ISIS) as a standard on Android phones.  Until then, we'll just have to play with tags and Android Beam.

Previously on Android A to Z: What is MWC?; Find more in the Android Dictionary

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3 years ago

What is Mobile World Congress? [Android A to Z]

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What is Mobile World Congress? The next big mobile trade show on our Android schedule is Mobile World Congress -- or MWC, for those in the know. It's in Barcelona, Spain, and has been since 2006 (and will be through 2018). Before that, it was known as 3GSM World and was in Cannes, France. This year will be the last at the Fira de Barcelona, a beautiful venue that actually allows for some sunlight (or dreary rain), with towers at the entrance and Palau Nacional rising at the far end.

MWC has a decidedly different feel than CES, which we just wrapped up in Las Vegas, or the bi-annual CTIA shows that rotate among different cities in the United States. Gone are the booth babes, and you'll see far more suits than you will in Sin City. That's not to say that Mobile World Congress is a boring show for Android -- far from it. MWC is where we'll see the latest and greatest from many of the major manufacturers. To wit:

And we've got meetings. And dinners. And dinner meetings. A slow show for Android, Mobile World Congress is not. Plus it's in Barcelona -- this year from Feb. 27 through March 1, a few weeks later than in years past -- smack on the western edge of the Mediterranean, full of culture and food. And phones. Feel free to hate us now.

Previously on Android A to Z: What is a launcher; Find more in the Android Dictionary

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3 years ago

Kinect meets Android, a new input method is born

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Youtube link for mobile viewing

Imagine a small projector attached to your Android device, and you can use your hand and touch the projected image to navigate the UI through a Kinect attached to a PC.  There's no need to just imagine it any longer, as the Android Kinect Projector Interface project is doing it now.  The developers have built a system where a projector is attached to a Galaxy Nexus, and a Kinect attached to a PC running Simple-Kinect-Touch 2.0 communicates motion to control the running system.  Using a custom AOSP ROM and TUIO for Android "touches" on the projected screen work just like touches on the physical screen would.  Badass tech indeed.  

Of course this is all unofficial and really beta alpha for now, but the idea is solid and the video shows us that it's feasible.  Maybe it's something we will see on the shelves one day.

Source: Recursive Penguin via Phandroid.

More: TUIO for Android; TUIO 2.0 Protocol Specifications

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3 years ago

Android A to Z: What is a launcher?

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What is an Android launcher? Probably the most powerful feature of Android is its ability to be customized. And that starts with what's typically called the "launcher." The launcher usually is considered to be the homescreens and app drawer, and they come in all sorts of flavors and designs.

When you hear people talk about "stock" Android, this usually is what they're referring to -- homescreens and app drawer unchanged from what Google includes in the open-sourced code. But that's just the tip of the iceberg. From there, you can download any number of third-party "launchers," which will change the look and functionality of the homescreens and the app drawer. Home screens can have different animations. Or different docks at the bottom. Or a specific number of home screens. App drawers can have more scrolling or sorting options. The possibilities might not be endless, but they're certainly numerous.

Google has included a lot of improvements in the Ice Cream Sandwich launcher, but third-party apps absolutely are not yet obsolete.) Some of the more popular third-party launchers include:

There is no shortage of third-party launchers. But they're not the only ones. Smartphone manufacturers all have their own launchers, too. HTC has its Sense UI, its own homescreen and its own app drawer, all nicknamed "Rosie." Motorola has long has its "Blur" user interface. Samsung has "TouchWiz." Don't like any of them? You can install a third-party launcher on top of the default user interface. And with as powerful as today's phones are, you can do so without any real degradation in performance.

Previously on Android A to Z: What is a kernel?; Find more in the Android Dictionary

 

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3 years ago

AC Asks: Are you using Google Currents?

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Google Currents is closing in on being two months old. Initial growth has seemed pretty impressive -- we've got around 178,000 subscribers -- but how much are you folks actually using it? We'll share some numbers here shortly. But for now, let's hear it. Are you using Google Currents? And if so, how often? And if you're looking to give it a shot, hit our subscribe link below.

Subscribe on Google Currents: Android Central; iMore; Mobile Nations

Are you using Google Currents?

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3 years ago

Android A to Z: What is a kernel?

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What is a kernel?  If you spend any time reading Android forums, blogs, how-to posts or online discussion you'll soon hear people talking about the kernel.  A kernel isn't something unique to Android -- iOS and MacOS have one, Windows has one, BlackBerry's QNX has one, in fact all high level operating systems have one.  The one we're interested in is Linux, as it's the one Android uses. Let's try to break down what it is and what it does.

Android devices use the Linux kernel, but it's not the exact same kernel other Linux-based operating systems use.  There's a lot of Android specific code built in, and Google's Android kernel maintainers have their work cut out for them.  OEMs have to contribute as well, because they need to develop hardware drivers for the parts they're using for the kernel version they're using.  This is why it takes a while for independent Android developers and hackers to port new versions to older devices and get everything working.  Drivers written to work with the Gingerbread kernel on a phone won't necessarily work with the Ice Cream Sandwich kernel.  And that's important, because one of the kernel's main functions is to control the hardware.  It's a whole lot of source code, with more options while building it than you can imagine, but in the end it's just the intermediary between the hardware and the software.

When software needs the hardware to do anything, it sends a request to the kernel.  And when we say anything, we mean anything.  From the brightness of the screen, to the volume level, to initiating a call through the radio, even what's drawn on the display is ultimately controlled by the kernel.  For example -- when you tap the search button on your phone, you tell the software to open the search application.  What happens is that you touched a certain point on the digitizer, which tells the software that you've touched the screen at those coordinates.  The software knows that when that particular spot is touched, the search dialog is supposed to open.  The kernel is what tells the digitizer to look (or listen, events are "listened" for) for touches, helps figure out where you touched, and tells the system you touched it.  In turn, when the system receives a touch event at a specific point from the kernel (through the driver) it knows what to draw on your screen.  Both the hardware and the software communicate both ways with the kernel, and that's how your phone knows when to do something.  Input from one side is sent as output to the other, whether it's you playing Angry Birds, or connecting to your car's Bluetooth.  

It sounds complicated, and it is.  But it's also pretty standard computer logic -- there's an action of some sort generated for every event.  Without the kernel to accept and send information, developers would have to write code for every single event for every single piece of hardware in your device.  With the kernel, all they have to do is communicate with it through the Android system API's, and hardware developers only have to make the device hardware communicate with the kernel.  The good thing is that you don't need to know exactly how or why the kernel does what it does, just understanding that it's the go-between from software to hardware gives you a pretty good grasp of what's happening under the glass.  Sort of gives a whole new outlook towards those fellows who stay up all night to work on kernels for your phone, doesn't it?

Previously on Android A to Z: What is the JIT?; Find more in the Android Dictionary

 

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3 years ago

Android A to Z: What is the JIT?

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What is the JIT?  JIT stands for "Just In Time," and we use it to describe a Dalvik JIT compiler, which was added to Android with the 2.2 release.  It compiles bytecode into native machine code at runtime.  Essentially it takes the code for an app, analyzes it and converts it into something that runs faster.  It does all this while the application is running, and that's where the "just in time" tag comes from.  The JIT compiler designed for Android also can do this with a very short "warm up" time, meaning it doesn't take very long to analyze the code before it starts working.  It stores information in a cache in your phone's RAM, which means it's not an ideal solution for devices with low memory.  It's been optimized to have a small footprint -- about 100K per process -- but even that is enough to impact performance on older models like the G1 or HTC Magic.  This is why most phones that came before the Nexus One never got an official version from Google -- hardware limitations.

You hear terms like "runs faster" or 4 to 5 times performance increase anytime you talk about Android's JIT compiler.  A JIT compiler simply saves CPU cycles -- more work can be done for each clock cycle.  This means applications that were throttled by CPU performance get faster, and apps that are "rate-limited" (run until they are finished without taxing the processor to the maximum) finish faster and use less battery because of it.  Not all applications see a significant speed increase, and most applications written with the NDK or in native code won't see an increase at all, as they don't use the Dalvik virtual machine.  

If all this reads like Greek to you, that's OK.  To the end user (that's you and me) all we should see is better performance in most of our applications.  We certainly saw that when Froyo was released for the Nexus One, and things have just gotten better with every release.  For the more technically inclined, check out the video from Android engineers Ben Cheng and Bill Buzbee during Google I/O 2010 where the JIT compiler was introduced.

Previously on Android A to Z: What's an IPS display?; Find more in the Android Dictionary

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3 years ago

Android A to Z: What's an IPS display?

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What is an IPS display? IPS stands for In-Plane Switching. It's commonly found in high-end monitors -- gaining mainstream notoriety in Apple's displays -- and has also found its way into tablets. The iPad uses IPS displays. ASUS has an IPS display in its Transformer Prime tablet. And Samsung has its own flavor of IPS in the Galaxy Tab 10.1, which is it calls Super PLS (Plane-Line Switching).

The long and short of it is that you get better color representation -- that is, whites are white, blacks and back, reds are red, etc. -- and better viewing angles. That's perhaps less of an issue with tablets than larger displays, because you're more likely to be using it directly in front of your face. But wider viewing angles are always better than not. (And we've seen some pretty horrid tablet displays in our day.)

There's not a lot of arguing against that, technically speaking, an IPS display is just "better" than a non-IPS display. If you have the option between an IPS or non-IPS display, we'd go with the former.

Previously on Android A to Z: H is for Hacking; Find more in the Android Dictionary

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3 years ago

Android A to Z: H is for Hacking

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Hacking.  It means a lot of different things to different people, and to the public at large it conjures up imagery of evil people in exotic places.  When we talk about hacking here at Android Central, we usually mean it in its original sense -- tearing into software (or hardware) and changing things until they fit our liking.  That's the good kind, and what we're going to talk about now.

Android hacking covers a lot of bases, from small but interesting things like changing statusbar icons and colors, to giant projects like custom-built AOSP ROMs, to super-geeky things like enabling the hidden FM Radio and 720p video recording on the Nexus One.  Most of the time installing and using any of these hacks will require your phone be rooted, and may even require a custom recovery designed to flash files that haven't been signed by the phone's manufacturer.  It can be complicated, and it pretty much voids any warranty that may be left on the device you're hacking away at.  

All these hacks you read and hear about are also usually pretty device-specific.  You'll not want to try things designed for the HTC Droid Incredible on your Motorola Photon, or even the HTC Droid Incredible 2.  This is where a little research and a lot of reading becomes necessary so you have a handle on what you're doing before you do it.  Armed with a little knowledge you sure can have a blast hacking away at your Android phone or tablet.

But we'd be remiss in not mentioning the bad hacking.  You know what it is. You should know when to avoid it. There are gray areas, to be sure, and we're not going to get overly preachy here. If it doesn't feel right, it probably isn't. Remember that real people work real hard on apps and hardware. Just sayin'.

Either way, you don't want to go it alone.  We'll tell you about the hacks and modifications here at Android Central, and the forums are full of people just like you and me who love our Android phones, and want to explore more about them.  Use them, and we can all hack together. 

Previously on Android A to Z: What is GSM?; Find more in the Android Dictionary

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3 years ago

Android A to Z: What is GSM?

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What is GSM? When it comes to Android devices, especially for us here in the U.S., there are two major differentiators that really have nothing to do with Android and everything to do with the carrier you plan on using the device on. When you're talking about a mobile device, you're either talking about a GSM device, or a CDMA device. GSM stands for Global System for Mobile Communications and is the network standard for much of the world. 

Of the four major carriers here in the United States, T-Mobile and AT&T use GSM technology. In Europe, you'll be hard-pressed to find something other than GSM. In Asia, you'll still find some CDMA carriers. 

A major advantage, at least from an end-user perspective, of GSM is the ability to easily swap devices, thanks to the SIM card. That's the little card (like what you see in the picture above) that contains are information that allows you to connect to a network, and it also can contain contact information. Pop the card into a new phone, and your phone number and contacts come with you.

There are a couple caveats to that, of course. One is that the phone you're using has to have radios to work on specific frequencies. While T-Mobile and AT&T are both GSM carriers and share the same EDGE radio frequency, they use different 3G frequencies, and most devices released in the United States can only connect to one or the other. (That's not always the case though -- some phones, like the GSM Galaxy Nexus, have the ability to do both) Another hurdle is that carriers usually "lock" the device to only use their own SIM cards. That is, if you put an AT&T SIM card into a T-Mobile phone, it'll ask for an unlock code. You can purchase the codes online, or the carrier may give it to you for free, if your account is in good standing. Outside the U.S., this is less of an issue because phones often are purchased "unlocked," albeit at higher prices than you'll see here.

But, wait. It gets more confusing. The new 4G LTE is a GSM standard. Therefore, Verizon and (soon) Sprint are using GSM technologies on their otherwise-CDMA phones. And both of those carriers have had "world phones" in the past -- traditional CDMA devices with GSM radios tucked in for use outside the United States.

Is GSM preferred over CDMA? For some, it's just a personal thing. For others, it's a perceived technical thing (such as building penetration). For others, it's a business thing, like being able to more easily use your personal device overseas with a prepaid SIM.   

Previously on Android A to Z: What is fastboot?; Find more in the Android Dictionary

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