What is the android operating system. What is Android: description for dummies

What is Android, and why is it needed? Many beginners, when buying a modern gadget, be it a tablet or a smartphone, ask a similar question. It is worth clarifying the situation and highlighting some of the advantages of this platform.

History of appearance

Today there are many devices that run on the Android platform. This operating system is designed for smartphones and tablets, watches and e-readers, game consoles and even Google glasses. Perhaps TVs and cars with Android support will appear soon.

The history of the creation of the OS began back in 2003. At that time, a small organization called Android inc was founded. Its founders were Rich Miner, Chris White, Andy Rubin and Nick Sears. Even then, some developments were underway that were planned to be implemented in the new operating system. The company carried out its activities in the strictest secrecy.

Soon the organization ran out of money, and there were no significant achievements in OS development. Due to the lack of results, investors could not be attracted. After a while, Google became interested in the development. In 2005, the company became the property of the search giant.

After this, the Open Handset Alliance Corporation was founded. It includes leading manufacturers of mobile devices. The Android platform was first introduced in 2007. As you know, it is based on the Linux kernel. The first version of this operating system was released in 2008.

What it is

Android is the operating system that powers smartphones, tablets, and many other devices. Thanks to this OS, even the most inexpensive phone will be able to gain new capabilities. The system will allow you to install various useful programs on your device that will help you make full use of all the functions of the device.

All necessary software can be downloaded from the Play Market. This site contains more than 700 thousand programs. A wide range will allow you to find any application you need. Using the operating system, you can easily access the Internet, watch video files, communicate on social networks, listen to music, take photos and immediately post them to your account or read e-books.

It is worth noting that the OS is completely free. Moreover, it is very easy to use. It won't take much time to understand the interface. Thanks to all its advantages, it has become the most widespread in the world. In 2014, more than 86% of devices operating on this platform were sold.

Video: Android phone

OS application

Since the advent of the Android operating system to the present day, developers have not been sitting idly by. The platform is constantly being improved. At the same time, its functionality is expanded by introducing new features.

Photo: Android 4.0 is the latest mobile version

The platform has become so popular and comfortable to use that many companies that develop modern gadgets have decided to release their devices based on this OS.

Using Android is not as difficult as it seems. With its help, you can perform almost the same actions on your device as on your computer.

The system provides several standard applications. Among them are:

• browser;
• Email;
• calendar;
• voice search;
• social network;
• navigator;
• weather;
• news.

All applications from Google.

Another nice plus is the ability to customize your desktop yourself. You can add an additional screen to your device where you can place shortcuts or widgets. You can also install any theme or wallpaper you like, thereby modifying the interface.

Why is it good

This OS has a number of advantages. The main ones are:

Stages of Android development

After the presentation of the first version of the platform, it was refined over the next year, as a result of which some system errors were corrected.

Five updated versions were introduced in 2009:

2010 was marked by the release of two more versions. They became:

The next development by the manufacturers was platform 3.0, which was presented in 2011. The new OS was specifically designed for tablets.

This system differs from the previous ones:

• improved interface;
• the ability to synchronize links with Google Chrome;
• external keyboard support;
• it is now possible to change the size of widgets on the screen;
• work on a multi-core processor.

The developers did not stop there and created Android 4.0, which was called “Ice Cream Sandwich”. This platform has become more universal. It can be used on both a phone and a tablet.

Photo: Android 4.0 “Ice Cream Sandwich”

The OS has a lot of new features and improvements:

• The notification panel has been changed;
• a way to control Internet traffic has been added;
• a voice dictation function has appeared;
• spell checking system;
• The camera application has been improved - a panoramic shooting mode, various effects and an image stabilizer have appeared;
• the browser has been updated;
• support for screenshots;
• updated security and gadget protection system.

Throughout 2012 and 2013, manufacturers worked on developing the Jelly Bean OS..

The next versions were 4.1, 4.2, 4.3. The new changes mainly affected the speed of the interface. Thanks to new developments, productivity has been increased. Now the GPU and central processor work in parallel.

The updated version of the platform has:

At the end of 2013, another version of Android 4.4 “Kitkat” was announced. The new platform has been optimized to run on cheaper devices that have 512 MB RAM.

There are also some changes here:

• Now in smartphones, contacts with whom the user communicates more often are located at the top of the list;
• the voice assistant is always active;
• automatic caller ID;
• subtitles are now displayed in the video player;
• the file downloader has an updated design;
• support for pedometer applications;
• Numerous errors and shortcomings have been corrected.

The company's latest development is version 5. The new OS is called "Lollipop". The main highlight was the Material design, which is distinguished by its versatility.

Competitors

The main competitors with which the Android platform has to fight for the palm are:

• Apple iPhoneOS;
• Microsoft Windows Mobile;
• RIM BlackBerry OS;
• Maemo/MeeGo;
• Samsung Bada OS;
• Palm webOS;
• Symbian OS.

Today, Android has become the most widespread mobile platform in the world than iOS. However, a presentation of the new Ubuntu Phone OS is planned soon. Perhaps it will become another serious competitor to Android.

Android devices

In 2008, the first device was released that ran on Android. The device was developed by HTC. It was a smartphone called HTC Dream. After this, several more phone manufacturers expressed a desire to produce mobile devices that support this operating system.

Soon a tablet based on the Android platform was announced. In 2009, a photo frame running on this OS appeared on the market. In addition, after 2 years, the Blue Sky organization developed a new wristwatch, which was called i’m Watch. They also support this system.

Camera manufacturers also decided to keep up and introduced the first camera in the world that runs on Android. The new product was released by Nikon. In addition, game consoles, e-books and media players operate on this platform. It is expected that some more devices will appear soon.

At this rate of development, the Android platform will become the absolute leader among other operating systems, leaving all competitors behind.

Thanks to a well-designed interface, easy use and reliable data protection, devices running this OS are certainly worthy of attention.

The logo of a green humanoid robot is now familiar to the vast majority of the planet’s inhabitants and can be found on devices from a variety of manufacturers. However, despite such great popularity, there are still people who do not know what Android is, or have an incomplete understanding of this operating system.

Another advantage of Android is its flexibility of settings. You can change your device beyond recognition by designing it according to your preferences. Android offers a lot of other undoubted advantages, but there is no point in listing them, because to each his own. For example, for some, the ability to synchronize Android with Google services is an advantage, but for others this is a completely useless function.

Each operating system has both advantages and disadvantages, of course, Android OS is no exception. If we compare Android with Symbian OS, Windows Mobile or iPhone OS, then this operating system is much inferior to them in security. The reason for this is that it is open source, which puts the smartphone at risk of being hacked. Even Google itself claims that every fifth Android application is potentially unsafe and can lead to theft of personal data.

One of the main disadvantages of the Android OS is its high consumption of Internet traffic. Most applications require a constant Internet connection to function properly. However, even if you do not use such programs, the operating system itself will consume traffic. The fact is that the OS settings by default have the function of sending reports on completed work, which are sent to developers. This leads to another significant drawback of Android - high power consumption.

Of course, the Android operating system also has other disadvantages, but they are not so significant, so we will not pay attention to them. Now you know what Android is and what advantages and disadvantages are typical for this OS. If you have any questions, ask them in the comments.

The definition of what an "Android" phone is is: it is designed primarily for touchscreen mobile devices. Originally developed for Google-backed Android Inc and later acquired by the company in 2005, the OS was introduced in 2007 with the Open Handset Alliance. The first phone on this platform was sold in October 2008.

Android is open source, which Google releases under the Apache license. This means that software can be developed using permissive licensing, making the OS quickly popular among professionals and developers. Therefore, speaking about what “Android” is in a phone, we can safely say that it is a platform that has a large community of developers who write applications that expand the functionality of devices. As a rule, all applications are written in a special version. In October 2012, there were approximately 700,000 applications available for download on Android phones, and the estimated number of applications downloaded from Google Play, the primary official store, was $25 billion.

These factors have contributed to Android becoming the most widely used smartphone platform in the world, overtaking Symbian in the fourth quarter of 2010. Many technology companies quickly caught on to the Android phone, and today it is widely used as an inexpensive, customizable, and easy-to-use operating system for high-tech devices.

Although it is designed primarily for phones and tablets, additional applications have been developed for televisions, game consoles, digital cameras and other electronics. If previously only the question of how to install Android on a phone was relevant, today the possibility of loading the OS on any gadget is being discussed. The open nature of Android has further influenced the formation of a large community of developers and enthusiasts who began to use its open source code as the basis for collaborative projects. As a result of these projects, new functions have appeared that are designed for advanced users.

Android is based on direct manipulation via touch input. All actions in this OS poorly correspond to real clicks, since you can use the menu with light finger movements. On such devices, the response to user input occurs immediately and is provided by the liquid contained in the displays with a touch interface. Internal ones (accelerometers, gyroscopes and sensors) are also used by some applications and allow them to respond to other user actions. These include changing the screen orientation from portrait to landscape, as well as the ability to perform various actions in games.

If we talk about what “Android” is in a phone visually, then the desktop consists of application icons and widgets. With this layout, icons are designed to launch the corresponding application, while widgets display live content - a weather forecast, a user's email status, or a news ticker.

The Android mobile operating system is already more than 5 years old and, despite the fact that the little green robot can be seen even in the most remote corners of the vast expanses of the Internet, there are still eccentrics who do not know what Android is. If you fall into this category, then this article will be your guide to understand what Android is and what to expect from a mobile device with a green robot on the package.

What is Android?

Android is the name of a mobile operating system created by the American company Google. Typically, the Android OS is installed on most different smartphones and tablets from a range of manufacturers and offers users access to many Google services such as Search, YouTube, Maps, Gmail and much more.

This means you can easily search for information you need online, watch videos, view maps, and write emails right from your smartphone, just like you did on your computer. But these simple elementary examples do not reveal even half of what the Android OS gives the user.

What can an Android smartphone do?

Android smartphones are highly customizable and can be customized to suit your tastes and needs: changing desktop wallpapers, changing themes and even operating system versions will allow you to completely change the look and interface of your Android device. You can download and install applications from the Internet and use them to do many things you need: check Facebook and Twitter, manage your bank account, order pizza and play games. You can schedule events directly on the calendar on your Android smartphone and view them on your home computer or laptop, or browse websites on your computer and continue watching them on your smartphone.

Another useful feature of Android OS is that it automatically backs up your contacts. Once you've set up your Android smartphone, you'll simply need to create a Google account or sign in to an existing one. Every time you save someone's number on your smartphone, it will automatically sync with your Google account.

The benefit of all this is that even if you break or lose your Android smartphone, all your numbers will be saved. When you sign in to your Google account on your new Android smartphone, all your contacts and friends' numbers will appear in your phone's address book instantly. There is no need to store backups yourself and manually add them back to your smartphone. Synchronization allows you to save all the information on your smartphone in this way: favorite websites, contacts, calendar entries, applications and games, and the synchronization process occurs unnoticed by the user, occurring in the background via Wi-Fi or another Internet connection.

What applications are there on Android smartphones?

There are hundreds and thousands of apps and games available for download from the Google Play Store (formerly Android Market). You'll be able to enjoy camera apps that let you take photos with artistic effects and filters, and music players that let you create your favorite playlists and listen to music directly from the Internet. You can customize the look of your Android device by changing the wallpaper to your own photos that you took with the built-in camera or to photos that you download from the Internet.

There are also many different on-screen widgets, downloading and installing which will allow you to quickly access your smartphone's settings without having to tinker with menus like on other non-Android devices. On the desktop of your Android smartphone, you can create your own system of shortcuts and menus to make it more convenient for you to use your smartphone.

There are many games available for the Android operating system, many of which are incredibly popular and many of which are free: Angry Birds, Draw Something, Temple Run...

How to install applications on an Android smartphone?

Most apps can be downloaded from the Google Play Store (equivalent to Apple's App Store), where you'll find both free and premium apps that you'll have to pay for. Some paid apps also have lite versions that are free to download and if you like them, you can download the full version of the game or app. Others, such as Angry Birds, are free but come with ads.

The same Google Account that allows you to back up your phone book contacts also gives you the option to open your account to buy content like apps and games directly from the Google Play Store. You can fund your account using a debit or credit card, and the initial setup will take you no more than five minutes if you do it from your computer.

Although there are over 1 million apps available to Android device users from the Google Play Store, some developers choose to make their apps available for download from their own websites. In order to download such applications, you will have to change some settings on your Android smartphone before visiting the developers' website. By downloading apps outside of the Google Play Store, you risk being attacked to steal your data or transmit a virus to your Android phone, so be careful if you choose to install apps this way.

If you update or change your Android smartphone, you will need to log into your Google account and you will be able to re-download all previously purchased applications without any problems.

What does an Android smartphone look like?

Android smartphones come in different shapes, colors and sizes. Some of them have super-fast processors, some have powerful cameras, and very few of them come with physical QWERTY keyboards.

All modern Android smartphones have touchscreens, the sizes of which vary, but in most cases they are at least 3 inches diagonally and many devices have much larger displays, such as the Samsung Galaxy Note 3. Smartphones with 5. 7-inchers are called “phablets” - a cross between a smartphone and a tablet.

The most popular Android smartphones are Samsung Galaxy S4 (5-inch), HTC One (4.7-inch), Sony Xperia Z1 Compact (4.3-inch) and Samsung Galaxy Ace 3 (4-inch). Some examples of older Android phones with a hardware QWERTY keyboard include the HTC Desire Z, HTC ChaCha, and Sony Xperia Mini Pro, but these models are inferior to smartphones with an on-screen keyboard in that smartphones without a physical keyboard are better at predicting words, phrases, and even entire sentences.

Who makes Android smartphones?

Any smartphone manufacturer is free to start making devices on the Android operating system if they want. The main manufacturers are HTC, Samsung, Sony, Acer, Alcatel, Asus, Huawei, LG, Motorola and ZTE. Other well-known mobile phone manufacturers such as Apple, Blackberry and Nokia do not produce Android smartphones, preferring other mobile operating systems instead of Android.

Does Google make Android smartphones?

Although Google owns the Android OS, they haven't made a single smartphone. However, they have been partnering with various smartphone manufacturers for many years and producing smartphones under their “Nexus” brand in foreign factories.

Google Nexus One (left) was made by HTC and ran on Android 2.1 Eclair, Google Nexus S (center left) was made by Samsung and ran on Android 2.3 Gingerbread, Samsung Galaxy Nexus (center) ran on Android 4.0 at launch Ice Cream Sandwich, LG Nexus 4 (center right) was the first smartphone to run Android 4.1/4.2 Jelly Bean out of the box, LG Nexus 5 (right) is the first smartphone to run Android 4.4 KitKat.

Google smartphones are now always the first to receive new updates to the Android operating system and are considered the flagship Android smartphones, although some smartphones from other manufacturers have larger screens, better cameras and more powerful hardware.

Android updates

Google is constantly working on new versions of Android. Releases of new versions of the operating system are rare; for now, they typically come out every six months or so, but Google hopes to slow that down to once a year.

The versions are usually referred to by a numerical code and name, which until now corresponded to the names of sweets and desserts, arranged in alphabetical order.

Android 1.5 Cupcake
Android 1.6 Donut
Android 2.1 Eclair
Android 2.2 Froyo
Android 2.3 Gingerbread
Android 3.2 Honeycomb - the first version of the OS specifically for tablets, launching on Motorola Xoom
Android 4.0 Ice Cream Sandwich: the first version of the OS to work on smartphones and tablets
Android 4.1 Jelly Bean: launched on Google Nexus 7 from Asus
Android 4.2 Jelly Bean: arrived on LG Nexus 4
Android 4.3 Jelly Bean
Android 4.4 KitKat: Launched on LG Nexus 5

Google also releases minor updates with bug fixes and improvements from time to time.

Android tablets

Just like Android smartphones, Android tablets come in a variety of shapes, colors, and sizes. They can range from 7 inches, like Asus's Google Nexus 7, to 10 inches, like the Nexus 10, and even larger ones.

It's a little surprising that some older Android tablets, such as the original Samsung Galaxy Tab, were launched on Android 2.2 Froyo, a version of the Android operating system designed for smartphones, while only Android 3.0 Honeycomb was the first release of the operating system specifically for tablets.

Older Android tablets running versions of Android OS prior to 3.0 Honeycomb weren't able to provide users with amenities like a redesigned YouTube app, 3D widgets, and other tablet-specific features like SwiftKey for tablets.

This operating system divide between tablets and smartphones was eliminated with the launch of Android Ice Cream Sandwich, which was designed to run on any type of device and scaled accordingly. Android Jelly Bean introduced a number of improvements to work on both smartphones and tablets, and this trend of working on both types of devices continues until the latest version of Android 4.4 KitKat.

Are Android updates free?

Android updates are free. Updates always bring a couple of new features and changes. With every update, Android speed and efficiency improves.

Most top Android smartphones are among the first to receive OS updates. Most Android smartphones receive one OS update during the period of use, and some receive two updates. The typical Android smartphone becomes obsolete in about a year, but some models remain relevant longer.

How to update Android?

Typically, Android updates are carried out "over the air", that is, sent directly to your Android smartphone, without the need to connect the device to a computer. Typically, as soon as your smartphone or tablet is due for an update, you will see a notification in a bar at the top of the screen. You will be asked to connect to WiFi to avoid data loss - the update can be quite large and downloading via mobile internet is not recommended.

Android updates are usually one-step and relatively simple, but in some cases you may need to back up some data (photos, videos, music) or apps that you saved before the update.

In some cases, such as some older Android smartphones from Sony and Samsung, you will need to install special software provided online in advance by the manufacturer.

Unlike Apple's iOS, where all users receive the update at the same time, regardless of device, Android updates are more fragmented depending on the manufacturer - this can be a little frustrating for users when they don't receive the update on time, unlike users of other smartphone models.

Those who have been using iPhone for a long time know how early versions of iOS worked. In fact, it was a single-tasking operating system that allowed only pre-installed applications to work in the background or interrupt the work of the current application: you are reading a book, they call you - the book reader is minimized, and a call window appears on the screen. But the reverse operation is impossible: the book reader not only cannot interrupt the work of other applications, but will also be killed immediately after being minimized.

The point of having such a system, of course, is to save processor, RAM, and battery life. Thanks to her (but not only) the iPhone could work quickly in conditions of limited resources and was very careful with the battery.

How the Android operating system works

Android has always worked differently. Here you can run many different applications and they will all remain in memory and can even run in the background. You open your browser, enter the address and, while the page is loading, launch your email client and read the letters. Everything is the same as on a desktop, with the exception that you don’t need to worry about closing applications, the system will do it itself when the RAM runs out or there is not enough to accommodate the application you are running (of course, rarely used applications will be used first ). This mechanism is called lowmemorykiller.

With root rights, lowmemorykiller settings can be adjusted directly or using special applications

An important element of the multitasking system were services. These are special application components that could run in the background under absolutely any conditions: the screen is on or off, the application is minimized or maximized, the services don’t even care whether the parent application is running at all. It simply said, “Hey Android, I need CPU resources, I want to do some calculations,” and it received those resources. In Android terminology, such a request to the system is called wakelock(or more precisely - processor wakelock).

However, supporting such a powerful and useful tool played a cruel joke on Google. A huge number of applications appeared that created services for every sneeze, constantly performed some kind of work and did not allow the smartphone to sleep. Having installed a hundred applications on a smartphone, the user received several dozen services, each of which periodically did something (updating the Twitter feed while the phone is sleeping is so important).

Things were so bad that Chinese manufacturers, not burdened with the task of maintaining compatibility with the original Android (this is required if you want to install the Play Store on your smartphones), simply disabled the mechanisms for maintaining the lifecycle of services for non-system applications in their smartphones.

Advanced users took a different route: they obtained root rights and installed the Greenify application, which allowed them to freeze the services of selected applications so that no one could wake them up. There were also more radical options, for example, demolishing all software that you use less than once a day.

Google itself has also taken some action to combat toxic services. A big step in this direction was made in Android 4.4, which introduced an intelligent mechanism that determined whether a service was running too much time and was using too much CPU, and, if so, nailed it in place and prevented it from starting. Even at a superficial glance, this version of the system had a battery life noticeably longer than the previous ones.

In Android 6.0, Google went even further and equipped it with a mechanism Doze, which after a certain period of inactivity of the smartphone (about one hour) transferred it to a special energy-saving mode. One of the features of this mode is a ban on wakelock, that is, neither applications nor services simply can wake up the smartphone to do any work. By eye, Android 6.0 did not live longer, so it is unknown whether this mechanism worked at all.

Doze work scale

And finally, in Android 8.0, Google took the radical step of disabling background services. But with two exceptions:

An application in some cases, for example when it is on the screen, can launch services, but Android will kill them after the application goes to sleep.
User visible services are still allowed. This is the so-called foreground service, a service that is visible in the notification panel and has an icon in the status bar.

It would seem that yes, services are evil, but what about applications like anti-theft, which should work unnoticed in the background? Or the same email client? Because of the need to periodically check email, should it hang in the notification bar?

Not really. Google has been moving towards banning services since version 5.0, where the so-called JobScheduler. This is a special subsystem that allows applications to ask Android to perform this or that work at such and such a time or when such and such an event occurs (connecting to the Internet, for example). And yes, JobScheduler is very similar to a similar function from iOS.

Binder

Contrary to popular belief, Android has used sandboxes to isolate applications since its earliest versions. And they were implemented in a very interesting way. Each application ran as a separate Linux user and thus only had access to its own directory inside /data/data .

Applications could communicate with each other and with the operating system only through the IPC mechanism Binder, which required authorization to perform a particular action. The same mechanism was used for several other purposes: with its help, the system notified applications about system events, such as an incoming call, an SMS, charging, and so on. Applications received messages and could respond to them.

Binder is powered by a driver in the Linux kernel and Service Manager

This feature has given Android very rich automation capabilities, which we know about thanks to applications such as Tasker, Automate or Locale. All these applications are available for Android 8, except that some dangerous features, such as turning on/off Airplane mode, are now prohibited for use by regular applications.

The warning system is based on intents, a special mechanism implemented on top of Binder and designed to exchange information between applications (or OS and applications), as well as launch application components. Using intents, you can notify applications about events, ask the system to open an application to process certain types of data (for example, to open a specific page in the browser, you just need to send a broadcast intent with a link to the page, and all applications that can display web pages will respond to it, either only the default browser) or simply launch a component of a particular application. For example, applications in Android are not launched directly, but using intents.

Unfortunately, like services, intents have become a problem for Google and Android users. The fact is that broadcast intents, used to notify applications about events, come immediately to all applications that have declared that they are able to respond to them. And in order for the application to respond to the intent, it must be launched. The picture turns out like this: there are twenty applications on the smartphone that can respond to the android.net.conn.CONNECTIVITY_CHANGE intent, and every time you connect to the network and disconnect from it, the system launches these applications so that they can respond to the intent. Just imagine how this affects energy consumption.

Google corrected this misunderstanding again in Android 8.0. Applications can now register broadcast intent handlers only while they are running (with minor exceptions).

Google Services

Google likes to flaunt the fact that Android is an open source operating system. This, of course, is not entirely true. On the one hand, Android code is truly open, which is why we have access to so many different custom firmwares. On the other hand, by building Android from official sources, you will receive a system without several important components: 1) individual drivers, the source codes of which are hidden by the manufacturer as a trade secret, 2) Google services, which are needed primarily to gain access to your account and launch Google Play and cloud backup.

Google Mobile Services is also responsible for many other things, including support for push notifications, Instant Apps, Google Maps, calendar access, location determination by cell towers and Wi-Fi routers, Smart Lock mechanism, which allows you to unlock the device in depending on certain conditions.

In modern versions of Android, Google services have taken on so much of the work that living without them turns out to be possible, but very problematic. And they are also not fun: the minimum version of the GApps package (which contains only Google and Google Play services) weighs more than 120 MB, and the services themselves are famous for their love of RAM and battery power. And they are also closed, that is, only Google itself knows what they can do.

You can download a package with Google services and applications for custom firmware from the website opengapps.org (the word open does not mean that they are open)

That is why the microG project was born, the task of which is to recreate the most important functionality of Google services in open source. Already now microG allows you to access your account, activate push notifications, access to Google maps and location determination from cell towers. And all this with a size of four mega and almost complete absence of requirements for RAM and battery life.

The project has its own build of LineageOS firmware, which out of the box includes microG and all the modifications necessary for its operation.

Linux kernel and runtime

Android is based on the Linux kernel. The kernel manages the resources of the smartphone, including access to hardware, management of RAM and permanent memory, starting, stopping and transferring processes between processor cores and many other tasks. Like any other OS, the kernel is the heart of Android, the central part without which everything else will fall apart.

Layer Cake Android

The presence of the Linux kernel, as well as a partially POSIX runtime environment (primarily the bionic library, based on the implementation of the standard C language library from OpenBSD), makes Android compatible with Linux applications. For example, the wpa_supplicant authentication system used to connect to Wi-Fi networks is exactly the same as in any Linux distribution. Early versions of Android used the standard Linux Bluetooth stack called bluez (later replaced by Qualcomm's implementation called Bluedroid). It even has its own console with a set of standard UNIX/Linux commands, implemented in the Toybox set, originally created for embedded Linux systems.

Most console applications written for Linux can be ported to Android by simple recompilation using a cross-compiler (the main thing is to use static compilation to avoid library conflicts), and having root rights, you can run a full-fledged . One caveat is that it can only be accessed through the console or using a VNC connection. There is also a Maru OS project that allows you to use your smartphone as a Debian-based PC when connected to a monitor. It promises the same function when connecting your smartphones to the monitor using the DeX dock.

Good old mc running in Android

Starting with version 4.4, Android can use the SELinux forced access control system to protect against hacking and obtain root rights. SELinux was developed by the US National Security Agency and, without going into details, allows you to limit applications (including low-level system components) in capabilities. And we are not talking about the powers that the user grants to applications, but about such things as system calls and access to certain files, despite standard UNIX access rights.

A series of Stagefright vulnerabilities that hit Android several years ago made it possible to gain control of the device simply by forcing the user to open an incoming MMS or a special file in the browser. The problem was in the Stagefright multimedia framework, which contained several buffer overflow vulnerabilities. When opening a specially prepared multimedia file, the exploit exploited the vulnerability and ran code on the device on behalf of Stagefright (which ran under root).

Google successfully closed all these bugs, and also worked on modularizing the framework code and running it in special SELinux domains. These domains prevent media processing components from using most Linux system calls, including the execve group system calls that were implicated in running the malicious code.

Today, SELinux is used to protect almost all Android system components. And this caused a sharp decrease in the number of bugs found in Android. But it led to hackers focusing on the kernel, or rather those very closed drivers, the code of which was not audited by anyone and whose security is not guaranteed (and it, as it turned out, is in a deplorable state).

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