Corning Gorillla Glass

Gorilla Glass is the registered trademark for a toughened glass, manufactured by U.S. glassmaker Corning, Inc.

It became highly popular as a cover glass for portable electronic devices such as high-end mobile phones.

The manufacturer claims that Gorilla Glass offers high scratch resistance and incredible hardness, which allows the use of thinner glass panels on devices, without the inherent fragility, which traditionally comes with thinner thickness.

The invention for manufacturing this sort of protective glass had supposedly been gathering dust for quite some years in Corning's warehouse, until Steve Jobs, Apple's CEO back then, commissioned Corning to develop a new scratch proof display cover glass for the first iPhone.

The rise of touchscreen phones popularity since then has turned the manufacturing of Gorilla Glass into a lucrative business niche for Corning.

In 2012, Corning introduced a second generation of the material, called "Gorilla Glass 2" and devices using it started shipping in the first half the same year. According to the manufacturer, the advantages of the second generation include even thinner construction, higher transparency to light and allows for even better touch sensitivity.

Gorilla Glass 3 was announced in 2013 and the popular Samsung Galaxy S4 (released in the first half of the year) is announced as the first phone to feature it.

The new generation is marketed as having Native Damage Resistance™. Marketing talk aside, the new glass reportedly provides enhanced scratch resistance, reduced scratch visibility, and better retained strength once a scratch occurs. According to the manufacturer, the Gorilla Glass 3 is stronger, and is 3x more scratch-resistant than Gorilla Glass 2. Plus some 40% less scratches are visible once they occur.

Source : GSMarena

NFC (Near Field Communication)

NFC is a short-range high frequency wireless communication technology that enables the exchange of data between devices over about a 10 cm distance.

NFC is an upgrade of the existing proximity card standard (RFID) that combines the interface of a smartcard and a reader into a single device. It allows users to seamlessly share content between digital devices, pay bills wirelessly or even use their cellphone as an electronic traveling ticket on existing contactless infrastructure already in use for public transportation.

The significant advantage of NFC over Bluetooth is the shorter set-up time. Instead of performing manual configurations to identify Bluetooth devices, the connection between two NFC devices is established at once (under a 1/10 second).

Due to its shorter range, NFC provides a higher degree of security than Bluetooth and makes NFC suitable for crowded areas where correlating a signal with its transmitting physical device (and by extension, its user) might otherwise prove impossible.

NFC can also work when one of the devices is not powered by a battery (e.g. on a phone that may be turned off, a contactless smart credit card, etc.)

Source : GSMarena

Long term evolution (LTE)

LTE is the next-step of the evolution of UMTS (3G) and HSDPA (3.5G). It's the only wireless network technology that's correctly called 4G. Some carries may market their high-speed HSDPA+ networks as 4G, but that's not technically correct.

Some of the improvements LTE brings along over the currently used wireless mobile radio technologies are a better spectral efficiency, lower costs, higher transfer speeds, improved services, etc.

LTE networks are widely available in the USA by carriers such as AT&T, Sprint and Verizon. In Europe, the network standard is not as widely spread and have limited coverage.

Theoretically, LTE networks should provide wireless data downlink speeds of up to 300Mbps and uplinkspeeds of up to 75Mbps.

Originally, LTE was conceived as an IP-based wireless system used purely for carrying data traffic. Network carriers were supposed to provide voice communication via their concurrent 2G/3G networks or by using VoIP. By popular request however, Voice over LTE (VoLTE) was a standardised system for transferring voice traffic over LTE. Currently, the availability of Voice over LTE (VoLTE) depends on the carrier implementation.

Unfortunately, the current implementations of LTE use different frequency bands in different countries, making interoperability an issue. LTE networks throughout the world can be seen utilizing one or several different network bands such as:

• Band 1, 2100MHz (Japan, Philippines, South Korea);
• Band 3, 1800MHz (Australia, Belgium, Finland, Germany, Hong Kong, Hungary, Italy, Singapore, Slovenia, Slovakia, South Korea, United Arab Emirates, UK)
• Band 4, 1700MHz (AT&T in the United States)
• Band 7, 2600MHz (Austria, Brazil, Canada, Finland, Germany, Hong Kong, Russia, Singapore, Sweden, Switzerland)
• Band 17, 700MHz (AT&T and Verizon in the United States, Canada)

Source: GSMarena

Odin mode

Odin mode (or Download mode) is for Samsung Galaxy phones what the name means. You are a God and the phone is a slave. In Odin mode, the user is able to flash whatever wants to the internal flash memory inside the phone by connecting phone to the computer via USB cable. As Odin mode is simple program (in the phone), poor user may not even flash main (Android) system, kernel, recovery system, but this is possible to repartition internal flash and reflash Odin mode itself. If something goes wrong and the Odin mode is broken (erased, rewritten, corrupted), the phone no longer boots and is hard-bricked. So Odin mode is dangerous. Because of this dangerous nature of Odin mode, Odin mode is usually used to only reflash main system or recovery (see warnings below) and if possible, recovery mode is used for flashing (as it is less dangerous).

Source : XDA

CWM

ClockworkMod Recovery (CWM) is a replacement recovery option for Android devices, made by Koushik "Koush" Dutta. It is based on the Android 2.1 (Eclair) recovery image. Features include Nandroid backup, adb shell, advanced update.zip options (ignore asserts and signature checks), and file browser for choosing update.zips

The Rom Manager app may be used for installing CWM, overwriting the device's stock recovery. As with the stock recovery, CWM can apply software changes to the device. Unlike the stock recovery, CWM is able to entirely replace the device's primary Android operating system ("flashing a new ROM"), including with aftermarket replacements such as CyanogenMod. Once installed, CWM it is accessed by turning your phone off, then triggering the bootloader prompt by holding down some device-dependent button combination as it is turned on.

CWM is also known as clockwork and CW recovery.

Source : XDA

How to Entering recovery mode on Your phone

This is possible to enter recovery mode by pressing some button combination during boot sequence of the device. The key combination differ from phone to phone, but manufactures usually has similar invocations for similar phones. You have to read a page with instruction for your phone to make sure that you are not doing something weird. When these keys are pressed, the device does not perform normal boot sequence. Instead of this, another partition is picked and kernel+recovery_apps is invoked from this recovery partition, so the rest of the flash is untouched (see custom recovery_apps list above). The combination of pressed keys has nothing to do with the recovery kernel+recovery_apps (ie. what is flashed to the recovery partition, this will be run). Sometimes there is no recovery flashed, so even keys are pressed, no recovery mode is invoked. You may still be able to flash own recovery to the device by Odin mode and use it later.

Example :

Source : XDA

Recovery Mode

Recovery Mode

In Android devices, Recovery is an Android-based, lightweight runtime environment separate from and parallel to the main Android operating system. Recovery's original purpose was:

§  to apply software updates to the device, e.g. OTA updates, and

§  to erase user data and cache, e.g. for troubleshooting or preparing the device for resale (factory reset) and

§  to run (another) external tool from microSD flash memory

Recovery is stored in a disk partition separate from the main Android partitions (boot/kernel, root/system). It contains its own Linux kernel, separate from the kernel of the main Android system. Because of separate kernel+recovery_apps, the device is able to boot into the recovery mode even main system is broken some way. Until this recovery partition is not broken, the user has nice tool to fix the device. The recovery has nothing to do with the rest of the (Android) system, so is completely independent.

The bootloader determines whether to boot Android or Recovery.

Recovery Mode

Custom recovery apps

The open-source community has extended the original Android Recovery system, to add other features:

§  system backup and restore (NANDroid),

§  the ability to apply Android changes that aren't approved by the manufacturers or carriers,

§  improved user interface, including using the touch screen instead of only the volume and power buttons, and

§  runs adbd, to support ADB connections.

The most popular custom recovery is ClockworkMod Recovery. Others are:

§  4EXT

§  Amon Ra Recovery

§  Team Win Recovery Project (TWRP)

Clock Workmod Recovery

Source : XDA

Bootloader

Bootloader

A bootloader is a computer program that loads an operating system (OS) or runtime environment for the computer after completion of the self-tests.

The bootloader configures the device to an initial known state and has a means to select where to start executing the kernel. It can allow you to make this selection, which give you for example the opportunity to start an alternative Linux kernel, or Windows. Because the bootloader is an essential component of the boot process, it is stored in non-volatile memory, such as flash memory.

Bootloaders are written by hardware vendors and are specialized for the hardware they run on.

For Android devices, the bootloader typically starts either Android or Recovery. Android bootloaders often have a basic interactive mode that can be triggered by holding the "volume down" button while the bootloader is executing.

Locked/unlocked bootloaders

A locked bootloader is one that will only boot an OS that it "approves" of. This may mean that device's boot partition has an approved digital signature, or the carrier ID (CID) hard-coded into the OS matches a value hard-coded into the bootloader itself. See also Wikipedia:Hardware restrictions#Verified/trusted/secure boot and Wikipedia:SIM lock.

For devices with a locked bootloader, booting an unsanctioned OS (e.g. CyanogenMod or Ubuntu) requires the device's owner to first unlock (or even replace[1]) the bootloader. Unlocking the bootloader sometimes voids the device's warranty. Procedures vary typically by manufacturer.

Bootloader unlocking should not be confused with Android rooting.

Source : XDA, Wikipedia