Android (operating system): Difference between revisions

Revision as of 01:06, 6 August 2025

Revision as of 05:26, 6 August 2025

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The storage of Android devices can be expanded using secondary devices such as [[SD card]]s. Android recognizes two types of secondary storage: ''portable'' storage (which is used by default), and ''adoptable'' storage. Portable storage is treated as an external storage device. Adoptable storage, introduced on Android 6.0, allows the internal storage of the device to be [[Non-RAID drive architectures#Concatenation (SPAN, BIG)|spanned]] with the SD card, treating it as an extension of the internal storage. This has the disadvantage of preventing the memory card from being used with another device unless it is [[disk formatting|reformatted]].<ref name="Ars Technica review">{{cite web |last=Amadeo |first=Ron |date=October 5, 2015 |title=Android 6.0 Marshmallow, thoroughly reviewed |url=https://arstechnica.com/gadgets/2015/10/android-6-0-marshmallow-thoroughly-reviewed/ |access-date=March 6, 2017 |website=[[Ars Technica]] |publisher=[[Condé Nast]]}}</ref>

Android 4.4 introduced the Storage Access Framework (SAF), a set of APIs for accessing files on the device's filesystem.<ref name="anandtech-sdkitkat">{{cite web |last=Ho |first=Joshua |title=Examining MicroSD changes in Android 4.4 |url=http://www.anandtech.com/show/7859/examining-microsd-changes-in-android-44 |archive-url=https://web.archive.org/web/20140314104428/http://www.anandtech.com/show/7859/examining-microsd-changes-in-android-44 |url-status=dead |archive-date=March 14, 2014 |access-date=March 28, 2014 |work=Anandtech}}</ref> As of Android 11, Android has required apps to conform to a data privacy policy known as ''scoped storage'', under which apps may only automatically have access to certain directories (such as those for pictures, music, and video), and app-specific directories they have created themselves. Apps are required to use the SAF to access any other part of the filesystem.<ref name=":32">{{Cite web |title=Behavior changes: Apps targeting Android 11 |url=https://developer.android.com/about/versions/11/behavior-changes-11 |access-date=August 18, 2020 |website=Android Developers |language=en}}</ref><ref>{{Cite web |title=Android Q Scoped Storage: Best Practices and Updates |url=https://android-developers.googleblog.com/2019/04/android-q-scoped-storage-best-practices.html |access-date=August 15, 2019 |website=Android Developers Blog}}</ref><ref>{{Cite web |title=Android Q privacy change: Scoped storage |url=https://developer.android.com/preview/privacy/scoped-storage |url-status=dead |archive-url=https://web.archive.org/web/20190711073559/https://developer.android.com/preview/privacy/scoped-storage |archive-date=July 11, 2019 |access-date=August 15, 2019 |website=Android Developers}}</ref>

=== Memory management ===

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==== Security patches ====

In August 2015, Google announced that devices in the [[Google Nexus]] series would begin to receive monthly security [[Patch (computing)|patches]]. Google also wrote that "Nexus devices will continue to receive major updates for at least two years and security patches for the longer of three years from initial availability or 18 months from last sale of the device via the [[Google Store]]."<ref>{{cite web |first1=Adrian |last1=Ludwig |first2=Venkat |last2=Rapaka |title=An Update to Nexus Devices |url=https://android.googleblog.com/2015/08/an-update-to-nexus-devices.html |website=Official Android Blog |date=August 5, 2015 |access-date=March 16, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170318164542/https://android.googleblog.com/2015/08/an-update-to-nexus-devices.html |archive-date=March 18, 2017 }}</ref><ref>{{cite web |first=Ryan |last=Whitwam |title=Google Announces New Update Policy For Nexus Devices Including Monthly Security Patches For 3 Years And Major OTAs For 2 Years From Release |url=http://www.androidpolice.com/2015/08/05/google-announces-new-update-policy-for-nexus-devices-including-monthly-security-patches-for-3-years-and-major-otas-for-2-years-from-release/ |website=Android Police |date=August 5, 2015 |access-date=March 16, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170126054028/http://www.androidpolice.com/2015/08/05/google-announces-new-update-policy-for-nexus-devices-including-monthly-security-patches-for-3-years-and-major-otas-for-2-years-from-release/ |archive-date=January 26, 2017 }}</ref><ref>{{cite web |first=Brandon |last=Chester |title=Google Commits To Monthly Security Updates For Nexus Devices |url=http://www.anandtech.com/show/9496/google-commits-to-monthly-security-updates-for-nexus-devices |website=[[AnandTech]] |publisher=[[Purch Group]] |date=August 5, 2015 |access-date=March 16, 2017 |url-status=livedead |archive-url=https://web.archive.org/web/20170317054707/http://www.anandtech.com/show/9496/google-commits-to-monthly-security-updates-for-nexus-devices |archive-date=March 17, 2017 }}</ref> The following October, researchers at the [[University of Cambridge]] concluded that 87.7% of Android phones in use had known but unpatched [[security vulnerabilities]] due to lack of updates and support.<ref>{{cite web |title=87% of Android devices insecure |url=http://androidvulnerabilities.org/press/2015-10-08 |website=Android Vulnerabilities |publisher=[[University of Cambridge]] |date=October 8, 2015 |access-date=March 11, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170222080441/http://www.androidvulnerabilities.org/press/2015-10-08 |archive-date=February 22, 2017 }}</ref><ref>{{cite web |first1=Daniel R. |last1=Thomas |first2=Alastair R. |last2=Beresford |first3=Andrew |last3=Rice |title=Security Metrics for the Android Ecosystem |url=https://www.cl.cam.ac.uk/~drt24/papers/spsm-scoring.pdf |publisher=[[Libraries of the University of Cambridge|Computer Laboratory]], [[University of Cambridge]] |access-date=March 16, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170222134830/https://www.cl.cam.ac.uk/~drt24/papers/spsm-scoring.pdf |archive-date=February 22, 2017 }}</ref><ref>{{cite web |first=Ron |last=Amadeo |title=University of Cambridge study finds 87% of Android devices are insecure |url=https://arstechnica.com/security/2015/10/university-of-cambridge-study-finds-87-of-android-devices-are-insecure/ |website=[[Ars Technica]] |publisher=[[Condé Nast]] |date=October 14, 2015 |access-date=March 11, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170312063812/https://arstechnica.com/security/2015/10/university-of-cambridge-study-finds-87-of-android-devices-are-insecure/ |archive-date=March 12, 2017 }}</ref> Ron Amadeo of ''[[Ars Technica]]'' wrote also in August 2015 that "Android was originally designed, above all else, to be widely adopted. Google was starting from scratch with zero percent market share, so it was happy to give up control and give everyone a seat at the table in exchange for adoption. [...] Now, though, Android has around 75–80 percent of the worldwide smartphone market—making it not just the world's most popular mobile operating system but arguably the most popular operating system, period. As such, security has become a big issue. Android still uses a software update chain-of-command designed back when the Android ecosystem had zero devices to update, and it just doesn't work".<ref>{{cite web |first=Ron |last=Amadeo |title=Waiting for Android's inevitable security Armageddon |url=https://arstechnica.com/gadgets/2015/08/waiting-for-androids-inevitable-security-armageddon/ |website=[[Ars Technica]] |publisher=[[Condé Nast]] |date=August 6, 2015 |access-date=March 11, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170312065601/https://arstechnica.com/gadgets/2015/08/waiting-for-androids-inevitable-security-armageddon/ |archive-date=March 12, 2017 }}</ref> Following news of Google's monthly schedule, some manufacturers, including Samsung and LG, promised to issue monthly security updates,<ref>{{cite web |first=Liam |last=Tung |title=After Stagefright, Samsung and LG join Google with monthly Android patches |url=https://www.zdnet.com/article/after-stagefright-samsung-and-lg-join-google-with-monthly-android-patches/ |website=[[ZDNet]] |publisher=[[CBS Interactive]] |date=August 6, 2015 |access-date=March 11, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170312051109/http://www.zdnet.com/article/after-stagefright-samsung-and-lg-join-google-with-monthly-android-patches/ |archive-date=March 12, 2017 }}</ref> but, as noted by Jerry Hildenbrand in ''Android Central'' in February 2016, "instead we got a few updates on specific versions of a small handful of models. And a bunch of broken promises".<ref>{{cite web |first=Jerry |last=Hildenbrand |title=Monthly security patches are the most important updates you'll never get |url=http://www.androidcentral.com/monthly-security-patches-are-most-important-updates-youll-never-get |website=Android Central |publisher=Mobile Nations |date=February 19, 2016 |access-date=March 11, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170115232057/http://www.androidcentral.com/monthly-security-patches-are-most-important-updates-youll-never-get |archive-date=January 15, 2017 }}</ref>

In a March 2017 post on Google's Security Blog, Android security leads Adrian Ludwig and Mel Miller wrote that "More than 735 million devices from 200+ manufacturers received a platform security update in 2016" and that "Our carrier and hardware partners helped expand deployment of these updates, releasing updates for over half of the top 50 devices worldwide in the last quarter of 2016". They also wrote that "About half of devices in use at the end of 2016 had not received a platform security update in the previous year", stating that their work would continue to focus on streamlining the security updates program for easier deployment by manufacturers.<ref>{{cite web |first1=Adrian |last1=Ludwig |first2=Mel |last2=Miller |title=Diverse protections for a diverse ecosystem: Android Security 2016 Year in Review |url=https://security.googleblog.com/2017/03/diverse-protections-for-diverse.html |quote=<!--More than 735 million devices from 200+ manufacturers received a platform security update in 2016. [..]-->We released monthly Android security updates throughout the year for devices running Android 4.4.4 and up—that accounts for 86.3 percent of all active Android devices worldwide. |website=Google Security Blog |date=March 22, 2017 |access-date=March 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170322141254/http://security.googleblog.com/2017/03/diverse-protections-for-diverse.html |archive-date=March 22, 2017 }}</ref> Furthermore, in a comment to ''[[TechCrunch]]'', Ludwig stated that the wait time for security updates had been reduced from "six to nine weeks down to just a few days", with 78% of flagship devices in North America being up-to-date on security at the end of 2016.<ref>{{cite web |first=Kate |last=Conger |title=Android plans to improve security update speed this year |url=https://techcrunch.com/2017/03/22/security-updates-are-still-slow-for-android-users/ |website=[[TechCrunch]] |publisher=[[AOL]] |date=March 22, 2017 |access-date=March 22, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170322144352/https://techcrunch.com/2017/03/22/security-updates-are-still-slow-for-android-users/ |archive-date=March 22, 2017 }}</ref>

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|author = Brian Klug

|publisher = [[AnandTech]]

|url-status = livedead

|archive-url = https://web.archive.org/web/20131119003547/http://www.anandtech.com/show/7516/android-44-factory-images-now-available-for-nexus-4-7-2012-and-2013-and-10

|archive-date = November 19, 2013