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Android (operating system)
12
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Copyright
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4Contents
Android (operating system) 12
3G24
APK (file format) 32
Contents33
ARM architecture 33
AVG Technologies 53
AdMob 56
Recognition 57
Notes 57
Amazon Appstore 57
Android (operating system) 59
Android Debug Bridge 72
Usage 73
Security 73
Android Developer Challenge 73
Android Developer Lab 76
Occurrences 76
Android lawn statues 77
Background 77
Statues 78
Android software development 78
Android version history 84
Android beta 85
Android 1. 0 85
Android 1. 1 86
Android 1. 5 Cupcake 87
Android 1. 6 Donut 87
Android 2. 0/2. 1 Eclair 88
Android 2. 2. x Froyo 89
Android 2. 3. x Gingerbread 90
Android 3. x Honeycomb 91
Android 4. 0. x Ice Cream Sandwich 93
Android 4. 1. x Jelly Bean 95
Androidland 96
5History 97
The store 97
Reception 97
Andy Rubin 97
Early life 98
Education 98
Career 98
List of patents 98
Apache Harmony 99
History 100
Initiation 100
Incompatibility with GNU Classpath 100
Difficulties to obtain a TCK license from Sun 100
Apple Inc. v. Samsung Electronics Co., Ltd. 100
Application programming interface 107
Application software 116
Terminology 117
Application software classification 118
Information worker software 120
Content access software 120
Entertainment software 120
Educational software 121
Enterprise infrastructure software 121
Simulation software 121
Media development software 121
Product engineering software 122
Avast!122
Baidu Yi 130
Features 130
Devices 130
BlackBerry OS 130
Release History 132
Availability 132
BlackBerry Fonts 133
BlackBerry Tablet OS 134
BlackBerry Tablet OS 134
Carrier IQ 138
Comparison of Android devices 146
6Officially released 147
Smartphones 147
Acer 147
Asus 149
HTC149
LG 155
Motorola159
Panasonic 163
Samsung 164
Sony 172
Sony Ericsson 176
Other manufacturers 179
Tablet computers 185
E-readers 191
Netbooks192
Smartwatch 192
Other devices 192
Future 193
Future Android smartphones 193
Future tablet computers 194
Future e-readers 194
Future game consoles 194
Other future devices 195
Unofficial and community ports 195
Comparison of Android e-book reader software 196
File formats supported 197
Navigation features 197
Display features 198
Edit-tool features 199
Book source management features 200
Other software e-book readers for Android 200
Comparison of Java and Android API 201
Virtual machine 201
System properties 202
Class library 202
java. lang package 202
Graphics and Widget library 202
Look and feel 202
Layout manager 202
7Comparison of netbook-oriented Linux distributions
203
Netbook distributions 203
Comparison 203
Features 203
Specific features 205
Google Trends 205
Comparison of smartphones 205
Hardware and OS 206
Networks and connectivity 222
CyanogenMod 226
Dalvik (software) 233
Eclipse (software) 236
Embedded Linux 241
History242
Devices coverage 242
Communities243
Advantages and Disadvantages 243
Fastboot243
Use 243
Firefox OS 244
GNU/Linux naming controversy 247
Galaxy Nexus 253
Gmail 259
Google 272
Google+ 273
Google Authenticator 283
Implementation 283
Technical description 283
Pseudocode 284
Technology 284
Google Buzz 284
Google Calendar 289
Google China 292
Google Chrome 298
Google Chrome OS 315
8Google Code 324
Google Contacts 327
Features 328
Google Currents 328
Google Currents Producer 329
910
11
Android (operating system)
Android (operating system)
Android
Home screen displayed by Samsung Galaxy Nexus, running
Android 4. 1 “Jelly Bean”
Company / developer Google, Open Handset Alliance,
Android Open Source Project
Programmed in C, C++, Java
OS family Unix-like, Linux
Working stateCurrent
Source model Open source
Initial release September 20, 2008
Latest stable release 4. 1 Jelly Bean / July 10, 2012; 2 months
ago
Marketing target Smartphones and Tablet computers
Available language(s) Multi-lingual
Package manager Google Play / APK
Supported platforms ARM, MIPS, x86
Kernel type Monolithic (modified Linux kernel)
Default user interface Graphical (Multi-touch)
License Apache License 2. 0
Linux kernel patches under GNU GPL v2
Official website www. android. com
Android is a Linux-based operating system designed primarily for
touchscreen mobile devices such as smartphones and tablet
computers, developed by Google in conjunction with the Open
Handset Alliance. Initially developed by Android Inc, whom
Google financially backed and later purchased in 2005, Android
was unveiled in 2007 along with the founding of the Open
Handset Alliance, a consortium of 86 hardware, software, and
telecommunication companies devoted to advancing open
standards for mobile devices.
Google releases the Android code as open-source, under the
Apache License. The Android Open Source Project (AOSP), lead by
Google, is tasked with the maintenance and further development
of Android. Additionally, Android has a large community of
12developers writing applications (“apps”) that extend the
functionality of devices. Developers write primarily in a customized
version of Java, and apps can be downloaded from online stores
such as Google Play (formerly Android Market), the app store run
by Google, or third-party sites. In June 2012, there were more than
600,000 apps available for Android, and the estimated number of
applications downloaded from Google Play was 20 billion.
The first Android-powered phone was sold in October 2008, and
by the end of 2010 Android had become the world’s leading
smartphone platform. It had a worldwide smartphone market share
of 59% at the beginning of 2012, and as of third quarter 2012, there
were 500 million devices activated and 1. 3 million activations per
day.
History
Android, Inc. was founded in Palo Alto, California, United States in
October 2003 by Andy Rubin (co-founder of Danger), Rich Miner
(co-founder of Wildfire Communications, Inc. ), Nick Sears (once
VP at T-Mobile), and Chris White (headed design and interface
development at WebTV) to develop, in Rubin’s words “. . . smarter
mobile devices that are more aware of its owner’s location and
preferences”. Despite the obvious past accomplishments of the
founders and early employees, Android Inc. operated secretly,
revealing only that it was working on software for mobile phones.
That same year, Rubin ran out of money. Steve Perlman, a close
friend of Rubin, brought him $10,000 in cash in an envelope and
refused a stake in the company.
Google acquired Android Inc. on August 17, 2005, making Android
Inc. a wholly owned subsidiary of Google. Key employees of
Android Inc. , including Andy Rubin, Rich Miner and Chris White,
stayed at the company after the acquisition. Not much was
known about Android Inc. at the time of the acquisition, but many
assumed that Google was planning to enter the mobile phone
market with this move.
At Google, the team led by Rubin developed a mobile device
platform powered by the Linux kernel. Google marketed the
platform to handset makers and carriers on the promise of
providing a flexible, upgradable system. Google had lined up a
series of hardware component and software partners and signaled
to carriers that it was open to various degrees of cooperation on
13their part.
Speculation about Google’s intention to enter the mobile
communications market continued to build through December
2006. Reports from the BBC and The Wall Street Journal noted that
Google wanted its search and applications on mobile phones
and it was working hard to deliver that. Print and online media
outlets soon reported rumors that Google was developing a
Google-branded handset. Some speculated that as Google was
defining technical specifications, it was showing prototypes to cell
phone manufacturers and network operators. In September 2007,
InformationWeek covered an Evalueserve study reporting that
Google had filed several patent applications in the area of mobile
telephony.
On November 5, 2007, the Open Handset Alliance, a consortium of
technology companies including Google, device manufacturers
such as HTC and Samsung, wireless carriers such as Sprint Nextel
and T-Mobile, and chipset makers such as Qualcomm and Texas
Instruments, unveiled itself. The goal of the Open Handset Alliance
is to develop open standards for mobile devices. On the same day,
the Open Handset Alliance unveiled Android as its first product, a
mobile device platform built on the Linux kernel version 2. 6.
The first commercially available phone to run Android was the
HTC Dream, released on October 22, 2008. In early 2010 Google
collaborated with HTC to launch its flagship Android device, the
Nexus One. This was followed later in 2010 with the Samsung-made
Nexus S and in 2011 with the Galaxy Nexus.
Description
The user interface in Android is based on the concept of direct
manipulation, using single- and multi-touch inputs like swiping,
tapping, pinching and reverse pinching to manipulate on-screen
objects. The response to user input is designed to be immediate
and provides a fluid touch interface. Internal hardware such
as accelerometers, gyroscopes and proximity sensors are used
by some applications to respond to additional user actions,
for example adjusting the screen from portrait to landscape
depending on how the device is orientated, or allowing the user
to steer a vechicle in a racing game by rotating the device,
simulating control of a steering wheel.
14Android devices boot to the homescreen, which is similar to
the desktop found on PCs, and is the primary navigation and
information point on the device. Android homescreens are
typically made up of app icons, which launch the associated app,
and widgets, which display live, auto-updating content such as the
weather forecast, the user’s email inbox, or a news ticker directly
on the homescreen. A homescreen may be made up of several
pages that the user can swipe back and forth between.
Always present along the top of the screen is a status bar, showing
information about the device and its connectivity. This status bar
can be ‘pulled’ down to reveal a notification screen where apps
may display important information or updates, such as a newly
received email or SMS text, in a way that doesn’t immediately
interrupt or inconvenience the user. In early versions of Android
these notifications could be tapped to open the relevant app,
but recent updates have provided enhanced functionality, such
as the ability to call a number back directly from the missed
call notification, without having to open the dialer app first.
Notifications are persistent until read or dismissed by the user.
While Android is designed primarily for smartphones and tablets,
the open and customizable nature of the operating system allows
it to be used on other electronics, including laptops and netbooks,
smartbooks, ebook readers, and smart TVs (Google TV). Further, the
OS has seen niche applications on wristwatches, headphones, car
CD and DVD players, smart glasses (Project Glass), refrigerators,
vehicle satnav systems, home automation systems, games
consoles, mirrors, cameras, portable media players landlines, and
treadmills.
The Android logotype was designed along with the Droid font
family by Ascender Corporation, the robot icon was designed by
Irina Blok. Android Green is the color of the Android Robot that
represents the Android operating system. The print color is PMS
376C and the RGB color value in hexadecimal is #A4C639, as
specified by the Android Brand Guidelines. The custom typeface of
Android is called Norad (cf. NORAD). It is only used in the text logo.
Linux
Android consists of a kernel based on the Linux kernel 2. 6
and Linux Kernel 3. x (Android 4. 0 onwards), with middleware,
libraries and APIs written in C and application software running
15on an application framework which includes Java-compatible
libraries based on Apache Harmony. Android uses the Dalvik
virtual machine with just-in-time compilation to run Dalvik dex-
code (Dalvik Executable), which is usually translated from Java
bytecode. The main hardware platform for Android is the ARM
architecture. There is support for x86 from the Android x86 project,
and Google TV uses a special x86 version of Android.
Android’s linux kernel has further architecture changes by Google
outside the typical Linux kernel development cycle. Android does
not have a native X Window System by default nor does it support
the full set of standard GNU libraries, and this makes it difficult
to port existing Linux applications or libraries to Android. But the
support of simple C and SDL applications is possible by injection
of a small java shim and usage of the JNI like e. g. in the Jagged
Alliance 2 port for Android.
Certain features that Google contributed back to the Linux
kernel, notably a power management feature called wakelocks,
were rejected by mainline kernel developers, partly because
kernel maintainers felt that Google did not show any intent to
maintain their own code. Even though Google announced in April
2010 that they would hire two employees to work with the Linux
kernel community, Greg Kroah-Hartman, the current Linux kernel
maintainer for the -stable branch, said in December 2010 that he
was concerned that Google was no longer trying to get their code
changes included in mainstream Linux. Some Google Android
developers hinted that “the Android team was getting fed up with
the process”, because they were a small team and had more
urgent work to do on Android.
Linux included the autosleep and wakelocks capabilities in the 3.
5 kernel, after many previous attempts at merger. The interfaces
are the same but the upstream Linux implementation allows for
two different suspend modes: to memory (the traditional suspend
that android uses), and to disk (hibernate, as it is known on the
desktop). In August 2011, Linus Torvalds said that “eventually
Android and Linux would come back to a common kernel, but it
will probably not be for four to five years”. In December 2011, Greg
Kroah-Hartman announced the start of the Android Mainlining
Project, which aims to put some Android drivers, patches and
features back into the Linux kernel, starting in Linux 3. 3. further
integration being expected for Linux Kernel 3. 4.
16The flash storage on Android devices is split into several partitions,
such as “/system” for the operating system itself and “/data”
for user data and app installations. In contrast to desktop Linux
distributions, Android device owners are not given root access to
the operating system for security reasons, and sensitive partitions
such as /system are read-only. However, root access on the
device can be obtained by exploiting security flaws in within
Android, which is used frequently by the open source community
to enhance the capabilities of their devices, but also by malicious
parties to install viruses and malware.
Android Open Source Project
The Android Open Source Project is led by Google, and tasked with
the maintenance and development of Android. According to the
project “The goal of the Android Open Source Project is to create a
successful real-world product that improves the mobile experience
for end users. “ AOSP also maintains the Android Compatibility
Program, defining an “Android compatible” device “as one that
can run any application written by third-party developers using
the Android SDK and NDK”, to prevent incompatible Android
implementations. The compatibility program is optional and free of
charge, with the Compatibility Test Suite also free and open-source.
Updates
Android version history
Android has a rapid release cycle, with new major versions
being released every six to nine months. Updates are typically
incremental in nature, gradually improving the software on a
regular schedule, rather than completely overhauling the system
every two to three years which is common for desktop operating
systems such as Windows. Between each major release, minor
interim releases are made available as often as necessary to fix
security issues and other software bugs. Most Android smartphones
and tablets are capable of receiving updates “over-the-air” which
allows the device to download and install updates without having
to be connected to a PC.
Compared to rival mobile operating systems such as iOS, Android
updates are typically very slow in reaching devices, often taking
many months from the offical Google release date to actually
being distributed to phones and tablets. In 2011, Google partnered
with a number of manufacturers and carriers to announce an
17“Android Update Alliance”, pledging to deliver timely updates for
every device for 18 months after its release. As of 2012, this alliance
has never been mentioned since.
Update delays are caused partly due to the extensive variation
in hardware which makes up the Android ecosystem: each
update must be tailored to the specific hardware in each device,
which varies greatly from device to device, as the official Google
source code only runs on their current flagship Nexus phone.
Porting Android to specific hardware is a time- and resource-
consuming process for device manufacturers, who prioritize their
newest devices and often leave older ones behind. Hence, older
smartphones are frequently not updated to the latest release of
Android if the manufacturer decides it’s not worth their time, even
if the phone is capable of running the update. This problem is
compounded when manufacturers customize Android with their
own unique interface and apps, as these modifications must be
reapplied to each new release of the operating system. Some
commentators have noted that manufacturers have a financial
incentive not to update their devices, as lack of updates for
existing devices fuels the purchase of newer ones.
Further delays can be introduced by wireless carriers who, after
receiving updates from manufacturers, customize and brand
Android to their needs and conduct extensive testing on their
networks before sending the update out to users.
Applications
Applications are usually developed in the Java language using the
Android Software Development Kit, but other development tools
are available, including a Native Development Kit for applications
or extensions in C or C++, Google App Inventor, a visual
environment for novice programmers and various cross platform
mobile web applications frameworks.
Applications can be acquired by end-users either through a store
such as Google Play or the Amazon Appstore, or by downloading
and installing the application’s APK file from a third-party site.
Google Play
Google Play
18Google Play is an online software store developed by Google for
Android devices. An application program (“app”) called “Play
Store” is preinstalled on most Android devices and allows users to
browse and download apps published by third-party developers,
hosted on Google Play. As of June 2012, there were more than
600,000 apps available for Android, and the estimated number of
applications downloaded from the Play Store exceeded 20 billion.
The operating system itself is installed on 400 million total devices.
Only devices that comply with Google’s compatibility requirements
are allowed to preinstall and access the Play Store. The app filters
the list of available applications to those that are compatible with
the user’s device, and developers may restrict their applications to
particular carriers or countries for business reasons.
Google offers many free applications in the Play Store including
Google Voice, Google Goggles, Gesture Search, Google Translate,
Google Shopper, Listen and My Tracks. In August 2010, Google
launched “Voice Actions for Android”, which allows users to search,
write messages, and initiate calls by voice.
Security
Android applications run in a sandbox, an isolated area of the
operating system that does not have access to the rest of the
system’s resources, unless access permissions are granted by
the user when the application is installed. Before installing an
application, the Play Store displays all required permissions. A game
may need to enable vibration, for example, but should not need
to read messages or access the phonebook. After reviewing these
permissions, the user can decide whether to install the application.
The sandboxing and permissions system weakens the impact of
vulnerabilities and bugs in applications, but developer confusion
and limited documentation has resulted in applications routinely
requesting unnecessary permissions, reducing its effectiveness. The
complexity of inter-application communication implies Android
may have opportunities to run unauthorized code.
Several security firms have released antivirus software for Android
devices, in particular, Lookout Mobile Security, AVG Technologies,
Avast!, F-Secure, Kaspersky, McAfee and Symantec. This software is
ineffective as sandboxing also applies to such applications, limiting
their ability to scan the deeper system for threats.
19Privacy
Android smartphones have the ability to report the location of Wi-Fi
access points, encountered as phone users move around, to build
databases containing the physical locations of hundreds of millions
of such access points. These databases form electronic maps to
locate smartphones, allowing them to run apps like Foursquare,
Latitude, Places, and to deliver location-based ads.
Third party monitoring software such as TaintDroid, an academic
research-funded project, can, in some cases, detect when
personal information is being sent from applications to remote
servers.
In March 2012, it was revealed that Android Apps can copy photos
without explicit user permission, Google responded they “originally
designed the Android photos file system similar to those of other
computing platforms like Windows and Mac OS. [. . . ] we’re taking
another look at this and considering adding a permission for apps
to access images. We’ve always had policies in place to remove
any apps [on Google Play] that improperly access your data. “
Licensing
The source code for Android is available under free and open
source software licenses. Google publishes most of the code
(including network and telephony stacks) under the Apache
License version 2. 0, and the rest, Linux kernel changes, under the
GNU General Public License version 2.
The Open Handset Alliance develops the changes to the Linux
kernel, in public, with source code publicly available at all times.
The rest of Android is developed in private, with source code
released publicly when a new version is released. Typically Google
collaborates with a hardware manufacturer to produce a flagship
device (part of the Google Nexus series) featuring the new version
of Android, then makes the source code available after that
device has been released.
In early 2011, Google chose to temporarily withhold the Android
source code to the tablet-only Honeycomb release, the reason,
according to Andy Rubin in an official Android blog post, was
because Honeycomb was rushed for production of the Motorola
20Xoom, and they did not want third parties creating a “really bad
user experience” by attempting to put onto smartphones a version
of Android intended for tablets. The source code was once again
made available in November 2011 with the release of Android 4. 0.
As Android is not completely released under a GPL compatible
license, e. g. Google’s code is under the Apache license, and also
the Android Market allows proprietary software, Richard Stallman
and the FSF are critical against Android and recommending the
usage of alternatives as Replicant.
Reception
Research company Canalys estimated in Q2 2009 that Android
had a 2. 8% share of worldwide smartphone shipments. By Q4 2010
this had grown to 33% of the market, becoming the top-selling
smartphone platform. This estimate includes the Tapas and OMS
variants of Android. By Q3 2011 Gartner estimates more than half
(52. 5%) of the smartphone market belongs to Android.
In February 2010 ComScore said the Android platform had 9. 0%
of the U. S. smartphone market, as measured by current mobile
subscribers. This figure was up from an earlier estimate of 5. 2% in
November 2009. By the end of Q3 2010 Android’s U. S. market share
had grown to 21. 4%.
In May 2010, Android’s first quarter U. S. sales surpassed that of the
rival iPhone platform. According to a report by the NPD group,
Android achieved 25% smartphone sales in the US market, up 8%
from the December quarter. In the second quarter, Apple’s iOS was
up by 11%, indicating that Android is taking market share mainly
from RIM, and still has to compete with heavy consumer demand
for new competitor offerings. Furthermore, analysts pointed to
advantages that Android has as a multi-channel, multi-carrier
OS. In Q4 2010 Android had 59% of the total installed user base of
Apple’s iOS in the U. S. and 46% of the total installed user base of
iOS in Europe.
As of June 2011, Google said that 550,000 new Android devices
were being activated every day — up from 400,000 per day a
month earlier — and more than 100 million devices had been
activated. Android hit 300,000 activations per day back in
December 2010. By July 14, 2011, 550,000 Android devices were
being activated by Google each day, with 4. 4% growth per
21week. On August 1, 2011, Canalys estimated that Android had
about 48% of the smartphone market share. On October 13, 2011,
Google announced that there were 190 million Android devices
in the market. As of November 16, 2011, during the Google
Music announcement “These Go to Eleven”, 200 million Android
devices had been activated. Based on this number, with 1. 9% of
Android devices being tablets, approximately 3. 8 million Android
Honeycomb Tablets have been sold. On February 27, 2012, Andy
Rubin announced that Google was activating over 850,000
Android smartphones and tablets daily.
In December 2011 it was announced the Pentagon has officially
approved Android for use by its personnel.
There has been some concern about the ease at which paid
Android apps can be pirated - i. e. downloaded for free without
the developer’s permission. Unlike the app store on iOS devices,
which is the only place where iOS apps may be downloaded and
installed from, Android apps can be downloaded and installed
from anywhere, which makes it trivial to install unauthorized
copies of apps from file sharing networks. In an interview with
Eurogamer, the developers of Football Manager 2009 stated that
the ratio of pirated players vs legimate players was 5:1 for their
game Football Manager 2009. In 2010, Google released a tool for
validating authorised purchases for use within apps, but developers
complained that this was insufficient and trivial to crack. Google
responded that the tool, especially its initial release, was intended
as a sample framework for developers to modify and build upon
depending on their needs, not as a finished security solution. Piracy
on Android remains an ongoing concern.
Usage share
Usage share of the different versions as of September 4, 2012.
Most Android devices to date still run the older OS version 2. 3. x
Gingerbread that was released on December 6, 2010.
Version Release date API level Distribution (September 4,
2012)
4. 1. x Jelly Bean July 9, 2012 16 1. 2%
4. 0. x Ice Cream Sandwich October 19, 2011 14-15 20. 9%
3. x. x Honeycomb February 22, 2011 11-13 2. 1%
2. 3. x Gingerbread December 6, 2010 9-10 57. 5%
2. 2 Froyo May 20, 2010 8 14%
222. 0, 2. 1 Eclair October 26, 2009 7 3. 7%
1. 6 Donut September 15, 2009 4 0. 4%
1. 5 CupcakeApril 30, 2009 3 0. 2%
Open source community
Android has an active community of developers and enthusiasts
who use the Android source code to develop and distribute their
own modified versions of the operating system. These community-
developed releases, the most widely used of which being
CyanogenMod, often bring new features and updates to devices
faster than through the official manufacturer/carrier channels,
albeit without as extensive testing or quality assurance. Community
releases often come pre-rooted and contain modifications
unsuitable for non-technical users, such as the ability to overclock
or over/undervolt the device’s processor.
Historically, the early responses of tablet and smartphone
manufacturers and mobile carriers were typically unsupportive
of third-party firmware development. Manufacturers expressed
concern about improper functioning of devices running unofficial
software and the support costs resulting from this. Moreover,
modified firmwares such as CyanogenMod sometimes offer
features for which carriers would otherwise charge a premium (e.
g. , tethering). As a result, technical obstacles including locked
bootloaders and restricted access to root permissions were
common in many devices. However, as community-developed
software has grown more popular, and following a statement
by the Librarian of Congress in the United States that permits
the “jailbreaking” of mobile devices, manufacturers and carriers
have softened their position regarding third party development,
with some, including HTC, Motorola, Samsung and Sony Ericsson,
providing support and encouraging development. As a result of
this, over time the need to circumvent hardware restrictions to
install unofficial firmware has lessened as an increasing number
of devices are shipped with unlocked or unlockable bootloaders,
similar to the Nexus series of phones, although usually requiring that
users waive their devices’ warranties to do so.
Copyrights and patents
Both Android and Android phone manufacturers have been
the target of numerous patent lawsuits. On August 12, 2010,
Oracle sued Google over claimed infringement of copyrights
and patents related to the Java programming language. Oracle
23originally sought damages up to $6. 1 billion, but this valuation
was rejected by a federal judge who asked Oracle to revise the
estimate. In response, Google submitted multiple lines of defense,
counterclaiming that Android did not infringe on Oracle’s patents
or copyright, that Oracle’s patents were invalid, and several other
defenses. They said that Android is based on Apache Harmony,
a clean room implementation of the Java class libraries, and an
independently developed virtual machine called Dalvik. In May
2012 the jury in this case found that Google did not infringe on
Oracle’s patents, and the trial judge ruled that the structure of the
Java APIs used by Google was not copyrightable.
In addition to lawsuits against Google directly, various proxy
wars have been waged against Android indirectly by targeting
manufacturers of Android devices, with the effect of discouraging
manufacturers from adopting the platform by increasing the costs
of bringing an Android device to market. Both Apple and Microsoft
have sued several manufacturers for patent infringement, with
Apple’s ongoing legal action against Samsung being a particularly
high-profile case. In October 2011 Microsoft said they had signed
patent license agreements with ten Android device manufacturers,
whose products account for 55% of the worldwide revenue for
Android devices. These include Samsung and HTC. Samsung’s
patent settlement with Microsoft includes an agreement that
Samsung will allocate more resources to developing and marketing
phones running Microsoft’s Windows Phone operating system.
Google has publicly expressed its dislike for the current patent
landscape in the United States, accusing Apple, Oracle and
Microsoft of trying to take down Android through patent litigation,
rather than innovating and competing with better products and
services. In 2011-2, Google purchased Motorola Mobility for US$12. 5
billion, which was viewed in part as a defensive measure to protect
Android, since Motorola Mobility held more than 17,000 patents. In
December 2011 Google bought over a thousand patents from IBM.
3G
3G
3G, short for 3rd Generation, is a term used to represent the
3rd generation of mobile telecommunications technology.
24This is a set of standards used for mobile devices and mobile
telecommunication services and networks that comply with
the International Mobile Telecommunications-2000 (IMT-2000)
specifications by the International Telecommunication Union.
3G finds application in wireless voice telephony, mobile Internet
access, fixed wireless Internet access, video calls and mobile TV.
Several telecommunications companies market wireless mobile
Internet services as 3G, indicating that the advertised service is
provided over a 3G wireless network. Services advertised as 3G
are required to meet IMT-2000 technical standards, including
standards for reliability and speed (data transfer rates). To meet
the IMT-2000 standards, a system is required to provide peak data
rates of at least 200 kbit/s (about 0. 2 Mbit/s). However, many
services advertised as 3G provide higher speed than the minimum
technical requirements for a 3G service. Recent 3G releases, often
denoted 3. 5G and 3. 75G, also provide mobile broadband access
of several Mbit/s to smartphones and mobile modems in laptop
computers.
The following standards are typically branded 3G:
the UMTS system, first offered in 2001, standardized by 3GPP,
used primarily in Europe, Japan, China (however with a different
radio interface) and other regions predominated by GSM 2G
system infrastructure. The cell phones are typically UMTS and GSM
hybrids. Several radio interfaces are offered, sharing the same
infrastructure:
The original and most widespread radio interface is called
W-CDMA.
The TD-SCDMA radio interface was commercialised in 2009 and is
only offered in China.
The latest UMTS release, HSPA+, can provide peak data rates up
to 56 Mbit/s in the downlink in theory (28 Mbit/s in existing services)
and 22 Mbit/s in the uplink.
the CDMA2000 system, first offered in 2002, standardized by
3GPP2, used especially in North America and South Korea, sharing
infrastructure with the IS-95 2G standard. The cell phones are
typically CDMA2000 and IS-95 hybrids. The latest release EVDO Rev
B offers peak rates of 14. 7 Mbit/s downstream.
The above systems and radio interfaces are based on spread
spectrum radio transmission technology. While the GSM EDGE
standard (“2. 9G”), DECT cordless phones and Mobile WiMAX
standards formally also fulfill the IMT-2000 requirements and are
25approved as 3G standards by ITU, these are typically not branded
3G, and are based on completely different technologies.
A new generation of cellular standards has appeared
approximately every tenth year since 1G systems were
introduced in 1981/1982. Each generation is characterized by
new frequency bands, higher data rates and non backwards
compatible transmission technology. The first release of the 3GPP
Long Term Evolution (LTE) standard does not completely fulfill
the ITU 4G requirements called IMT-Advanced. First release LTE
is not backwards compatible with 3G, but is a pre-4G or 3. 9G
technology, however sometimes branded “4G” by the service
providers. Its evolution LTE Advanced is a 4G technology. WiMAX is
another technology verging on or marketed as 4G.
Overview
The following common standards comply with the IMT2000/3G
standard:
EDGE, a revision by the 3GPP organization to the older 2G GSM
based transmission methods, utilizing the same switching nodes,
base station sites and frequencies as GPRS, but new base station
and cellphone RF circuits. It is based on the three times as efficient
8PSK modulation scheme as supplement to the original GMSK
modulation scheme. EDGE is still used extensively due to its ease of
upgrade from existing 2G GSM infrastructure and cell-phones.
EDGE combined with the GPRS 2. 5G technology is called EGPRS,
and allows peak data rates in the order of 200 kbit/s, just as the
original UMTS WCDMA versions, and thus formally fulfills the IMT2000
requirements on 3G systems. However, in practice EDGE is seldom
marketed as a 3G system, but a 2. 9G system. EDGE shows slightly
better system spectral efficiency than the original UMTS and
CDMA2000 systems, but it is difficult to reach much higher peak
data rates due to the limited GSM spectral bandwidth of 200 kHz,
and it is thus a dead end.
EDGE was also a mode in the IS-135 TDMA system, today ceased.
Evolved EDGE, the latest revision, has peaks of 1 Mbit/s downstream
and 400kbit/s upstream, but is not commercially used.
The Universal Mobile Telecommunications System, created and
revised by the 3GPP. The family is a full revision from GSM in terms of
encoding methods and hardware, although some GSM sites can
be retrofitted to broadcast in the UMTS/W-CDMA format.
W-CDMA is the most common deployment, commonly operated
26on the 2,100 MHz band. A few others use the 850, 900 and 1,900
MHz bands.
HSPA is an amalgamation of several upgrades to the original
W-CDMA standard and offers speeds of 14. 4 Mbit/s down and
5. 76 MBit/s up. HSPA is backwards compatible with and uses the
same frequencies as W-CDMA.
HSPA+, a further revision and upgrade of HSPA, can provide
theoretical peak data rates up to 168 Mbit/s in the downlink
and 22 Mbit/s in the uplink, using a combination of air interface
improvements as well as multi-carrier HSPA and MIMO. Technically
though, MIMO and DC-HSPA can be used without the “+”
enhancements of HSPA+
The CDMA2000 system, or IS-2000, including CDMA2000 1x and
CDMA2000 High Rate Packet Data (or EVDO), standardized by
3GPP2 (differing from the 3GPP), evolving from the original IS-95
CDMA system, is used especially in North America, China, India,
Japan, South Korea, Southeast Asia, Europe and Africa.
CDMA2000 1x Rev. E has an increased voice capacity (in excess of
three times) compared to Rev. 0 EVDO Rev. B offers downstream
peak rates of 14. 7 Mbit/s while Rev. C enhanced existing and new
terminal user experience.
While DECT cordless phones and Mobile WiMAX standards
formally also fulfill the IMT-2000 requirements, they are not usually
considered due to their rarity and unsuitability for usage with
mobile phones.
Detailed breakdown of 3G systems
The 3G (UMTS and CDMA2000) research and development projects
started in 1992. In 1999, ITU approved five radio interfaces for IMT-
2000 as a part of the ITU-R M. 1457 Recommendation; WiMAX was
added in 2007.
There are evolutionary standards (EDGE and CDMA) that are
backwards-compatible extensions to pre-existing 2G networks
as well as revolutionary standards that require all-new network
hardware and frequency allocations. The cell phones used utilise
UMTS in combination with 2G GSM standards and bandwidths,
but do not support EDGE. The latter group is the UMTS family,
which consists of standards developed for IMT-2000, as well as the
independently developed standards DECT and WiMAX, which were
included because they fit the IMT-2000 definition.
Can also be used as an upgrade to PDC or D-AMPS.
27development halted in favour of LTE.
also known as FOMA; UMTS is the common name for a standard
that encompasses multiple air interfaces.
also known as UTRA-FDD; W-CDMA is sometimes used as a
synonym for UMTS, ignoring the other air interface options.
also known as UTRA-TDD 3. 84 Mcps high chip rate (HCR)
also known as UTRA-TDD 1. 28 Mcps low chip rate (LCR)
While EDGE fulfills the 3G specifications, most GSM/UMTS phones
report EDGE (“2. 75G”) and UMTS (“3G”) functionality.
History
3G technology is the result of ground-breaking research
and development work carried out by the International
Telecommunication Union (ITU) in the early 1980s. 3G specifications
and standards were developed after fifteen years of persistence
and hard work. The technical specifications were made available
to the public under the name IMT-2000. The communication
spectrum between 400 MHz to 3 GHz was allocated for 3G. Both
the government and communication companies unanimously
approved the 3G standard. The first pre-commercial 3G network
was launched by NTT DoCoMo in Japan in 1998, branded as
FOMA. It was first available in May 2001 as a pre-release (test)
of W-CDMA technology. The first commercial launch of 3G was
also by NTT DoCoMo in Japan on 1 October 2001, although it
was initially somewhat limited in scope; broader availability of the
system was delayed by apparent concerns over its reliability.
The first European pre-commercial network was an UMTS network
on the Isle of Man by Manx Telecom, the operator then owned
by British Telecom, and the first commercial network (also UMTS
based W-CDMA) in Europe was opened for business by Telenor in
December 2001 with no commercial handsets and thus no paying
customers.
The first network to go commercially live was by SK Telecom in
South Korea on the CDMA-based 1xEV-DO technology in January
2002. By May 2002 the second South Korean 3G network was by KT
on EV-DO and thus the Koreans were the first to see competition
among 3G operators.
The first commercial United States 3G network was by Monet Mobile
Networks, on CDMA2000 1x EV-DO technology, but this network
provider later shut down operations. The second 3G network
28operator in the USA was Verizon Wireless in July 2002 also on
CDMA2000 1x EV-DO. AT&T Mobility is also a true 3G UMTS network,
having completed its upgrade of the 3G network to HSUPA.
The first pre-commercial demonstration network in the southern
hemisphere[dubious – discuss] was built in Adelaide, South Australia
by m. Net Corporation in February 2002 using UMTS on 2,100 MHz.
This was a demonstration network for the 2002 IT World Congress.
The first commercial 3G network was launched by Hutchison
Telecommunications branded as Three or “3” in June 2003.
Emtel Launched the first 3G network in Africa.
By June 2007, the 200 millionth 3G subscriber had been connected.
This is only 6. 7% of the 3 billion mobile phone subscriptions
worldwide. In the countries where 3G was launched first – Japan
and South Korea – 3G penetration is over 70%. In Europe the
leading country for 3G penetration is Italy with a third of its
subscribers migrated to 3G. Other leading countries for 3G use
include UK, Austria, Australia and Singapore at the 20% migration
level. A confusing statistic is counting CDMA2000 1x RTT customers
as if they were 3G customers. If using this definition, then the total
3G subscriber base would be 475 million at June 2007 and 15. 8% of
all subscribers worldwide.
Adoption
3G was relatively slow to be adopted globally. In some instances,
3G networks do not use the same radio frequencies as 2G so
mobile operators must build entirely new networks and license
entirely new frequencies, especially so to achieve high data
transmission rates. Other delays were due to the expenses of
upgrading transmission hardware, especially for UMTS, whose
deployment required the replacement of most broadcast towers.
Due to these issues and difficulties with deployment, many
carriers were not able to or delayed acquisition of these updated
capabilities.
In December 2007, 190 3G networks were operating in 40 countries
and 154 HSDPA networks were operating in 71 countries, according
to the Global Mobile Suppliers Association (GSA). In Asia, Europe,
Canada and the USA, telecommunication companies use
W-CDMA technology with the support of around 100 terminal
designs to operate 3G mobile networks.
29Roll-out of 3G networks was delayed in some countries by the
enormous costs of additional spectrum licensing fees. (See
Telecoms crash. ) The license fees in some European countries were
particularly high, bolstered by government auctions of a limited
number of licenses and sealed bid auctions, and initial excitement
over 3G’s potential.
The 3G standard is perhaps well known because of a massive
expansion of the mobile communications market post-2G and
advances of the consumer mophone. An especially notable
development during this time is the smartphone (for example, the
iPhone, and the Android family), combining the abilities of a PDA
with a mobile phone, leading to widespread demand for mobile
internet connectivity. 3G has also introduced the term “mobile
broadband” because its speed and capability make it a viable
alternative for internet browsing, and USB Modems connecting to
3G networks are becoming increasingly common.
Patents
It has been estimated that there are almost 8,000 patents declared
essential (FRAND) related to the 483 technical specifications
which form the 3GPP and 3GPP2 standards. Twelve companies
accounted in 2004 for 90% of the patents (Qualcomm, Ericsson,
Nokia, Motorola, Philips, NTT DoCoMo, Siemens, Mitsubishi, Fujitsu,
Hitachi, InterDigital, and Matsushita).
Even then, some patents essential to 3G might have not been
declared by their patent holders. It is believed that Nortel and
Lucent have undisclosed patents essential to these standards.
Furthermore, the existing 3G Patent Platform Partnership pool has
little impact on FRAND protection, because it excludes the four
largest patents owners for 3G.
Features
Data rates
ITU has not provided a clear definition of the data rate users can
expect from 3G equipment or providers. Thus users sold 3G service
may not be able to point to a standard and say that the rates it
specifies are not being met. While stating in commentary that “it
30is expected that IMT-2000 will provide higher transmission rates: a
minimum data rate of 2 Mbit/s for stationary or walking users, and
384 kbit/s in a moving vehicle,” the ITU does not actually clearly
specify minimum or average rates or what modes of the interfaces
qualify as 3G, so various rates are sold as 3G intended to meet
customers expectations of broadband data.
Security
3G networks offer greater security than their 2G predecessors. By
allowing the UE (User Equipment) to authenticate the network it is
attaching to, the user can be sure the network is the intended one
and not an impersonator. 3G networks use the KASUMI block cipher
instead of the older A5/1 stream cipher. However, a number of
serious weaknesses in the KASUMI cipher have been identified.
In addition to the 3G network infrastructure security, end-to-end
security is offered when application frameworks such as IMS are
accessed, although this is not strictly a 3G property.
Applications of 3G
The bandwidth and location information available to 3G devices
gives rise to applications not previously available to mobile phone
users. Some of the applications are:
Mobile TV
Video on demand
Video Conferencing
Telemedicine
Location-based services
Global Positioning System (GPS)
Evolution
Both 3GPP and 3GPP2 are currently working on extensions to
3G standard that are based on an all-IP network infrastructure
and using advanced wireless technologies such as MIMO. These
specifications already display features characteristic for IMT-
Advanced (4G), the successor of 3G. However, falling short of the
bandwidth requirements for 4G (which is 1 Gbit/s for stationary and
100 Mbit/s for mobile operation), these standards are classified as 3.
9G or Pre-4G.
3GPP plans to meet the 4G goals with LTE Advanced, whereas
31Qualcomm has halted development of UMB in favour of the LTE
family.
On 14 December 2009, Telia Sonera announced in an official press
release that “We are very proud to be the first operator in the world
to offer our customers 4G services. “ With the launch of their LTE
network, initially they are offering pre-4G (or beyond 3G) services in
Stockholm, Sweden and Oslo, Norway.
APK (file format)
APK (file format)
APK
Filename extension . apk
Internet media type application/vnd. android. package-archive
Type of format Package management system, file archive
Container for Software package
Extended from JAR and ZIP
Most Android phones, like the Galaxy Nexus, allow installation of
applications directly via APK files or indirectly via Google Play
Android application package file (APK) is the file format used
to distribute and install application software and middleware
onto Google’s Android operating system. To make an APK file,
a program for Android is first compiled, and then all of its parts
are packaged into one file. This holds all of that program’s code
(such as . dex files), resources, assets, certificates, and manifest
file. As is the case with many file formats, APK files can have any
name needed, but must end with the four character, three letter
extension, . apk.
APK files are ZIP file formatted packages based on the JAR file
format, with . apk file extensions. The MIME type associated with
APK files is application/vnd. android. package-archive.
Contents
1 Contents
32Contents
An APK file is an archive that usually contains the following folders:
META-INF directory:
MANIFEST. MF: the Manifest file
CERT. RSA: The certificate of the application.
CERT. SF: The list of resources and SHA-1 digest; for example:
Signature-Version: 1. 0
Created-By: 1. 0 (Android)
SHA1-Digest-Manifest: wxqnEAI0UA5nO5QJ8CGMwjkGGWE=
...
Name: res/layout/exchange_component_back_bottom. xml
SHA1-Digest: eACjMjESj7Zkf0cBFTZ0nqWrt7w=
...
Name: res/drawable-hdpi/icon. png
SHA1-Digest: DGEqylP8W0n0iV/ZzBx3MW0WGCA=
lib: the directory containing the compiled code that is specific to
a software layer of a processor, the folder is split into more folders
within it:
armeabi: compiled code for all arm based processors only
armeabi-v7a: compiled code for all armv7 and above based
processors only
x86: compiled code for x86 processors only
mips: compiled code for mips processors only
res: the directory containing resources not compiled into resources.
arsc (see below).
AndroidManifest. xml: An additional Android manifest file,
describing the name, version, access rights, referenced library files
for the application. This file may be in Android binary XML that can
be converted into human-readable plaintext XML with tools such
as AXMLPrinter2, apktool, or Androguard.
classes. dex: The classes compiled in the dex file format
understandable by the Dalvik virtual machine
resources. arsc : a file containing pre-compiled resources, such as
binary XML for example.
ARM architecture
ARM architecture
ARM (formerly Advanced RISC Machine and Acorn RISC
Machine) is a reduced instruction set computer (RISC) instruction
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